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`nx_sbr_key_candidate.nx` source

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1// nx_sov_build_run.nx -- FULLY SOVEREIGN, REUSABLE build runner (operator: "no sh and no c build,
2// from the hardware layer up"). Generalizes nx_retire_gcc_orchestrator from hardcoded targets to ANY
3// module passed as argv[1]. The build path is bits-up sovereign end to end:
4//     nx_cc_sovereign.elf   <module>.nx  ->  _build/<module>.s        (the team's SELF-HOSTED compiler)
5//     nxasm_x86_main.elf    <module>.s   ->  _build/<module>.sov.elf  (the team's x86-64 assembler+linker)
6//     _build/<module>.sov.elf                                          (run it; exit = its exit)
7// ⚠OUTPUT PATH IS _build/, RELATIVE TO CWD -- NOT /tmp/. These three lines said /tmp/ until 2026-07-30,
8// left stale by the flock change that moved artifacts to a per-target _build/<name>.lock+.s+.sov.elf so
9// concurrent sweeps stop overwriting each other mid-build. A doc that disagrees with the code is a defect,
10// not a nit: it is why callers hunt for the artifact, and it hid a REAL brick hazard -- nx_hostctl
11// cmd_buildrun (nx_hostctl.nx) ONCE read only /tmp/<name>.sov.elf, which made this runner and that
12// supervisor a MATCHED PAIR that had to ship together or every /api/build failed.
13// CLOSED -- VERIFIED 2026-08-17 BY READING THE LIVE SOURCE, not by assuming: cmd_buildrun now probes the
14// ABSOLUTE .../nishihost/buildroot/_build/<name>.sov.elf FIRST (the parent is not in the child's CWD, so
15// it must name it absolutely), falls back to /tmp/ for pre-flock builders, and its failure line NAMES
16// BOTH paths. The pairing constraint no longer holds and this runner ships alone.
17// The old line also cited :3089 while the code now sits near :3571 -- a stale line number is the tell.
18//   * A STALE HAZARD NOTE IS ITSELF A HAZARD: it makes the next reader either avoid a safe change or
19//     hunt a defect that was already fixed. This estate has the receipt -- a standing RED-gate list that
20//     nobody re-measured cost NINE sessions the SAME nine investigations, and 5 of the 9 were already
21//     green. Re-measure a warning before repeating it.
22// NO gcc, NO bash, NO .sh anywhere. Orchestration is NishiLang sys_fork/dup3/execve/wait4.
23// Recompile-retry guards the known-good compiler's empty-.s nondeterminism. Usage:
24//     nx_sov_build_run.elf <module-basename-in-runtime/_hdl_build>
25
26
27// license_tier: ORIGINAL   Reuses the _run spine from nx_retire_gcc_orchestrator.
28import "nx_syscalls.nx"
29import "nx_itoa_lib.nx"   // shared MSB-first emitter (zero-alloc)
30import "nx_sha256.nx"     // CONTENT identity for the tree-canon admission (2026-08-06)
31import "nx_import.nx"     // the SAME closure resolver nx_cc uses -> content-addressed build cache (B2, 2026-08-17)
32import "nx_builddeploy_lib.nx"  // THE ruler for "may this build write a consumer-visible binary" (2026-08-26)
33import "nx_build_key_identity_lib.nx"
34import "nx_build_canon_input_lib.nx"  // Refuse absent or malformed admission evidence before compilation.
35
36// TOOLCHAIN NAMES -- the binaries that BUILD everything else, so they may never be installed as a
37// side effect of a build (see the refusal at the install site; seq1464).
38// ⚠BOTH COMPILER NAMES: the module is `nx_compile_x86` but it ships as `nx_cc_sovereign.elf`, so a
39// guard that knew only one name would leave the other door open -- which is exactly the door the
40// regressed compiler came through. `nx_sov_build_run` is listed because a runner that can overwrite
41// ITSELF mid-build is the same hazard pointed inward.
42// st_mtime seconds, -1 when absent. Offset 88 is the channel proven by _freshness_gate T5 and used
43// unchanged by nx_staging_guard / nx_tree_diff / nx_gate_verdict_lib -- same offset, never a fourth copy
44// of the number. Used by the canon admission to tell STALENESS from a FORK.
45const SBR_STATBUF: i64 = 256
46const SBR_STAT_MTIME_OFF: i64 = 88
47func sbr_mtime(path: *u8) -> i64 {
  let sb: *u8 = sys_mmap(SBR_STATBUF)
  if sys_fstatat(path, sb) != 0 { sys_munmap(sb, SBR_STATBUF); return 0 - 1 }
  let p: *i64 = ((sb as i64) + SBR_STAT_MTIME_OFF) as *i64
  let v: i64 = p[0]
  sys_munmap(sb, SBR_STATBUF)
  return v
54}
55
56func sbr_name_is(a: *u8, b: *u8) -> i64 {
  var i: i64 = 0
  while a[i] != (0 as u8) { if a[i] != b[i] { return 0 } i = i + 1 }
  if b[i] != (0 as u8) { return 0 }
  return 1
61}
62func sbr_is_toolchain(name: *u8) -> i64 {
  if sbr_name_is(name, "nx_compile_x86" as *u8) == 1 { return 1 }
  if sbr_name_is(name, "nx_cc_sovereign" as *u8) == 1 { return 1 }
  if sbr_name_is(name, "nxasm_x86_main" as *u8) == 1 { return 1 }
  if sbr_name_is(name, "nxasm_x86" as *u8) == 1 { return 1 }
  if sbr_name_is(name, "nx_sov_build_run" as *u8) == 1 { return 1 }
  return 0
69}
70
71// ⚠⚠A DAEMON'S SERVING-ROOT TWIN IS NOT A CACHE, IT IS THE DEPLOYED ARTIFACT (2026-08-07).
72// refresh-IF-PRESENT is right for an ordinary organ: the next fork picks up the fresh bytes and
73// LM-026 staleness is retired. For a DAEMON it is a DEPLOY -- the sovereign supervisor health-probes,
74// finds the process unresponsive, and respawns FROM DISK, so the refreshed file becomes the running
75// binary with no promote, no canary, no health gate, no .prev and no rollback.
76// This is the SAME argument the toolchain guard above already makes, applied to the class that has the
77// same property: the artifact is re-executed by something other than the caller.
78//   ★★★★★★ A FLAG WHOSE NAME PROMISES NO SIDE EFFECT, ON A TREE WHERE A SUPERVISOR RESPAWNS FROM
79//   DISK, IS A DEPLOY WITH EXTRA STEPS.
80// MEASURED INCIDENT: `nx_sov_build_run nx_tools_api_serve --build-only` refreshed the serving-root
81// twin; the supervisor respawned onto it; netstat then showed ZERO listeners on :18096 with four live
82// instances. The agent surface was down for every seat. The caller had explicitly chosen NOT to deploy
83// and believed --build-only meant it.
84// Daemons have exactly ONE lawful update route: an organ_kind.conf row plus health-checked
85// /api/deploy, which validates, banks .prev and auto-rolls-back. This makes that route the only one
86// BY CONSTRUCTION rather than by convention -- the same upgrade the toolchain got after seq1464.
87//
88// RETURNS 1 declared daemon · 0 not a daemon · -1 UNPROVEN (conf unreadable).
89// The catastrophic few are ALSO hardcoded, so a missing or edited conf cannot silently re-open the
90// hole on the two surfaces every other seat depends on. ★ DATA-DRIVE THE LIST, HARDCODE THE BLAST.
91func sbr_is_daemon(name: *u8) -> i64 {
  if sbr_name_is(name, "nx_tools_api_serve" as *u8) == 1 { return 1 }
  if sbr_name_is(name, "nx_mgmt_api" as *u8) == 1 { return 1 }
  let szp: *i64 = sys_mmap(16) as *i64
  // ⚠THIS PATH MUST TOLERATE THE CWD ANCHOR -- FIXED 2026-08-15, AND IT HAD DISABLED THE GUARD.
  // main() chdir's into buildroot/ whenever the runner is started from the serving root (which is how
  // nx_job_run, the supervisor and every operator invoke it). This BARE path therefore resolved to
  // buildroot/knowledge/status/organ_kind.conf, WHICH DOES NOT EXIST -- the conf lives at the nishihost
  // root (37,596 B, verified both ways). sys_read_file returned 0, this returned -1 = UNPROVEN, and the
  // caller's UNPROVEN branch WRITES THE BINARY ANYWAY and prints its warning AFTERWARDS.
  // NET EFFECT, and it is not theoretical: the daemon guard has been silently OFF since the anchor
  // landed, so every daemon built through this lane went straight to the SERVING ROOT with no canary,
  // no health gate and no .prev -- the supervisor respawns from disk, so that write IS a deploy.
  // MEASURED TODAY: a `--build-only` invocation deployed nx_docportal_admin_daemon.
  // This same file ALREADY learned the lesson for tree-canon ("the manifest is ../knowledge/... because
  // main() anchors CWD to buildroot") and applied it there. It was missed here.
  // ★★★★★★A GUARD THAT CANNOT READ ITS OWN RULEBOOK DOES NOT FAIL LOUD, IT FAILS ABSENT -- AND AN
  // ABSENT GUARD IS INDISTINGUISHABLE FROM A GUARD THAT APPROVED. The build-admission check twenty
  // lines below gets the same question right (rc=5 CANNOT-MEASURE -> REFUSE); this one waved through.
  // Anchored path FIRST, bare path second, so the answer is correct from EITHER cwd rather than
  // trading one broken vantage for the other.
  var buf: *u8 = sys_read_file("../knowledge/status/organ_kind.conf" as *u8, szp)
  if (buf as i64) == 0 { buf = sys_read_file("knowledge/status/organ_kind.conf" as *u8, szp) }
  if (buf as i64) == 0 { return 0 - 1 }
  let n: i64 = szp[0]
  if n <= 0 { return 0 - 1 }
  var nl: i64 = 0
  while name[nl] != (0 as u8) { nl = nl + 1 }
  let pat: *u8 = "daemon" as *u8
  var i: i64 = 0
  while i < n {
      // ⚠⚠THE EOL SCAN USED A SENTINEL THAT CLOBBERED ITS OWN CURSOR -- FIXED 2026-08-15, AND IT HAD
      // MADE THIS ENTIRE LOOKUP DEAD. The old form was:
      //     while e < n { if buf[e] == 10 { e = n + 1 } else { e = e + 1 } }
      //     if e > n { e = e - 1 }
      // On finding a newline it wrote n+1 INTO e to break, destroying the position it had just found;
      // e-1 then yields n, never the newline index. So every "line" spanned the whole rest of the
      // buffer, `i = e + 1` pushed i past n, and the outer loop ran EXACTLY ONCE -- on a first line
      // that begins with '#' and is skipped as a comment. sbr_is_daemon therefore returned 0 for every
      // name whenever the file was readable: not a wrong answer, a lookup that never ran.
      // ★★★★★★THE TELL WAS ALREADY IN THE SOURCE: the two hardcoded `nx_tools_api_serve` /
      // `nx_mgmt_api` early-returns above are a workaround for a table lookup that never matched. WHEN
      // A DATA-DRIVEN CHECK HAS HARDCODED EXCEPTIONS, SUSPECT THE LOOKUP, NOT THE DATA.
      // This is the estate's named recurring defect ("a loop-exit sentinel written into the search
      // cursor erases the answer -- use a flag"); separate cursor, explicit flag, cursor preserved.
      var e: i64 = i
      var eol: i64 = 0
      while eol == 0 {
          if e >= n { eol = 1 } else {
              if buf[e] == (10 as u8) { eol = 1 } else { e = e + 1 }
          }
      }
      if buf[i] != (35 as u8) {
          if i + nl < e {
              var k: i64 = 0
              var ok: i64 = 1
              while k < nl { if buf[i+k] != name[k] { ok = 0; k = nl } else { k = k + 1 } }
              if ok == 1 {
                  if buf[i+nl] == (32 as u8) {
                      var j: i64 = i + nl
                      var found: i64 = 0
                      while j + 6 <= e {
                          var m: i64 = 0
                          var eq: i64 = 1
                          while m < 6 { if buf[j+m] != pat[m] { eq = 0; m = 6 } else { m = m + 1 } }
                          if eq == 1 { found = 1; j = e }
                          j = j + 1
                      }
                      if found == 1 { return 1 }
                  }
              }
          }
      }
      i = e + 1
  }
  return 0
167}
168const SBR_MAGIC_4096: i64 = 4096   // read-chunk size (folded from the buildroot branch's rule-11 sweep, 2026-07-29 merge)
169
170// ---- CONTENT IDENTITY FOR THE TREE-CANON ADMISSION (2026-08-06) ----
171// The admission below used to compare BYTE SIZES, and its own comment said so honestly:
172//   "SIZE IS A SCREEN, NOT PROOF OF IDENTITY -- equal-size rewrites pass here;
173//    nx_treecanon_gate stays the tree-level instrument."
174// THAT DELEGATION WAS NOT AN IMPLEMENTATION. nx_treecanon_gate compared sizes too, so NOTHING in
175// the build lane ever checked content, and each half looked reasonable only because it assumed the
176// other half was doing the work. A MUTATION-CLASS DEFECT PRESERVES SIZE BY CONSTRUCTION, and one
177// had already escaped into this very buildroot: _hdl_build/nx_media_extract.nx held `if hit != 0`
178// where the authoring tree held `if hit == 0` -- one byte, 4389 bytes on BOTH sides.
179// Canon rows now compare sha256 whenever the authoring tree publishes a digest manifest, and fall
180// back to the byte-size screen when it does not. STRICTLY STRONGER, NEVER WEAKER.
181const SBR_SHA_HEX: i64 = 64
182const SBR_QMARK: i64 = 63           // '?' fills the digest slot when a file is unreadable / row absent
183// sys_read_file reserves filesize+16, but 4 GiB when lseek(END) reports 0 -- freeing an empty file
184// as "0+16" would leak 4 GiB of address space per call and walk into RLIMIT_AS.
185const SBR_EMPTY_RESERVE: i64 = 4294967296
186func sbr_sha_hex(path: *u8, out: *u8) -> i64 {
  let ln: *i64 = sys_mmap(16) as *i64
  ln[0] = 0
  let buf: *u8 = sys_read_file(path, ln)
  if (buf as i64) == 0 { sys_munmap(ln as *u8, 16); return 0 - 1 }
  let n: i64 = ln[0]
  let d: *u8 = sys_mmap(48)
  sha256_digest(buf, n, d)
  if n > 0 { sys_munmap(buf, n + 16) } else { sys_munmap(buf, SBR_EMPTY_RESERVE + 16) }
  sys_munmap(ln as *u8, 16)
  var i: i64 = 0
  while i < 32 {
      let v: i64 = d[i] as i64
      let hi: i64 = (v >> 4) & 15
      let lo: i64 = v & 15
      if hi < 10 { out[i*2] = (48+hi) as u8 } else { out[i*2] = (87+hi) as u8 }
      if lo < 10 { out[i*2+1] = (48+lo) as u8 } else { out[i*2+1] = (87+lo) as u8 }
      i = i + 1
  }
  sys_munmap(d, 48)
  out[SBR_SHA_HEX] = 0 as u8
  return 0
208}
209
210const SBR_OK:           i64 = 0
211const SBR_USAGE:        i64 = 2
212const SBR_COMPILE_FAIL: i64 = 3
213const SBR_ASM_FAIL:     i64 = 4
214const SBR_ADMIT_REFUSED: i64 = 6   // build admission said no; distinct from a compile/assemble failure
                                 // (3 and 4 raw would COLLIDE with COMPILE_FAIL/ASM_FAIL -- a retry-later
                                 // signal must never decode as a broken build)
217const SBR_CANON_REFUSED: i64 = 7   // canon evidence unavailable, invalid, or divergent
218const SBR_CANON_PATH_BYTES: i64 = 512
219const SBR_RUNTIME_PREFIX_BYTES: i64 = 8
220const SBR_MIN_ASM_BYTES: i64 = 128    // empty/failed .s is ~0-byte header; the smallest real program (_min42) is 540B
221const SBR_MAX_RETRIES:   i64 = 12
222// ---- BUILD DEADLINE (2026-08-16) ---------------------------------------------------------------
223// A build that HANGS is not a build that FAILED, and the two demand OPPOSITE responses -- the same
224// law the exit codes above already encode ("a retry-later signal must never decode as a broken
225// build"). MEASURED that day: nx_cc SPUN FOREVER on a specific source (a br_comp_border variant in
226// nx_browser_bisect.nx). With no deadline anywhere in this runner the child burned a core
227// indefinitely; two such spinners took the host from load_centi=542 to 1394, at which point
228// nx_ctxtop REFUSED to run ("host already saturated"). Only a human noticing stopped it.
229// nx_gate_build_sweep already carries "timeout per-build deadline in ms, default 180000" -- this is
230// that same shape, applied to the runner every organ is built through.
231const SBR_TIMEOUT_RC:  i64 = 0 - 9   // sbr_run sentinel: NEGATIVE, so it cannot collide with a real
                                   // exit code (0..255) nor with the 128+signal convention above
233const SBR_BUILD_TIMEOUT: i64 = 8     // process exit code; next free after CANON_REFUSED=7
234const SBR_SIGKILL:     i64 = 9
235const SBR_POLL_MS:     i64 = 100     // wait4(WNOHANG) poll interval; fork+WNOHANG liveness is already
                                   // host-proven by nx_initlive_probe -- composed, not re-verified
237const SBR_NO_DEADLINE: i64 = 0       // explicit: RUNNING the built program must never be time-boxed
238// DERIVED FROM MEASUREMENT, NOT TASTE: the largest closure this runner compiles in practice is
239// nx_browser's 29-import set (9,243,150 B of .s), which completed in under 5 minutes on this host,
240// timed repeatedly on 2026-08-16. 900000 ms is 3x that worst observed case, so a legitimate build
241// cannot trip it while an infinite loop is still bounded. Raise it here if a bigger closure appears
242// -- and if you do, say what you measured.
243const SBR_BUILD_DEADLINE_MS: i64 = 900000
244
245func sbr_puts(s: *u8) -> i64 { var n: i64 = 0; while s[n] != (0 as u8) { n = n + 1 } sys_write(1, s, n); return 0 }
246// MIGRATED to the shared emitter (debt 1785563586). The old body mmapped a scratch buffer
247// per call and never freed it. At PAGE granularity that is 4096B leaked PER CALL -- the
248// defect that took 28.5GB of a 36GB host in nx_ts_lumadiff (2MB input, ~3.66M calls).
249// nxi_* is MSB-first, allocates NOTHING, and emits identical bytes including the sign.
250func sbr_putn(v: i64) -> i64 { nxi_out(v); return 0 }
251
252// append NUL-terminated s into dst at off; return new offset (no NUL written)
253func sbr_cat(dst: *u8, off: i64, s: *u8) -> i64 { var i: i64 = 0; while s[i] != (0 as u8) { dst[off+i] = s[i]; i = i + 1 } return off + i }
254
255// bounded byte-range equality on (base,offset,len) pairs -- conf/manifest lines are not NUL-terminated
256func sbr_ceq_at(a: *u8, ao: i64, al: i64, b: *u8, bo: i64, bl: i64) -> i64 {
  if al != bl { return 0 }
  var i: i64 = 0
  while i < al { if a[ao+i] != b[bo+i] { return 0 } i = i + 1 }
  return 1
261}
262
263func sbr_exitcode(status: i64) -> i64 { return (status >> 8) & 0xff }
264
265// Decimal argv value -> integer, or -1 on ANYTHING malformed (empty, sign, units, stray char).
266// REFUSES rather than defaulting: a deadline that silently became 0 would restore the exact
267// unbounded-hang this flag exists to prevent, and it would do it while looking configured.
268func sbr_atoi(s: *u8) -> i64 {
  var v: i64 = 0
  var i: i64 = 0
  while s[i] != (0 as u8) {
      let c: i64 = s[i] as i64
      if c < 48 { return 0 - 1 }
      if c > 57 { return 0 - 1 }
      v = v * 10 + (c - 48)
      i = i + 1
  }
  if i == 0 { return 0 - 1 }
  return v
280}
281
282// fork + optional stdout/stderr redirect + execve; parent waits; returns child's WEXITSTATUS,
283// OR 128+signal if the child died to a signal (shell convention).  Without the signal check a
284// SEGFAULTED tool decodes as rc=0 = silent fake success (caught live 2026-06-09: nxasm segfaulted
285// on the 2.4MB compiler .s, the runner reported the assemble step OK, and the missing ELF
286// surfaced later as a confusing execve-127).  Composes [[feedback-evidence-driven-live-grading]].
287// redir_err>=0 -> child stderr (e.g. /dev/null to mute nx_cc's symbol-table dump).
288// deadline_ms > 0 time-boxes the child: poll wait4(WNOHANG), and on expiry SIGKILL it, REAP it (never
289// leave a zombie behind a timeout) and return SBR_TIMEOUT_RC. deadline_ms = SBR_NO_DEADLINE waits
290// forever, which is correct for RUNNING the built program -- a daemon or a long job must not be shot.
291func sbr_run(path: *u8, argv: *i64, envp: *i64, redir_out: i64, redir_err: i64, deadline_ms: i64) -> i64 {
  let pid: i64 = sys_fork()
  if pid == 0 {
      if redir_out >= 0 { sys_dup3(redir_out, 1, 0) }
      if redir_err >= 0 { sys_dup3(redir_err, 2, 0) }
      sys_execve(path, argv, envp)
      sys_exit(127)
  }
  let st: *i64 = sys_mmap(16) as *i64
  if deadline_ms <= 0 {
      sys_wait4(pid, st, 0)
  } else {
      // Deadline measured against the CLOCK, not against a count of sleeps: accumulating the poll
      // interval drifts by however long each wait4 itself took, and a drifting deadline is a
      // threshold nobody can state.
      let t0: i64 = sys_now_ms()
      var settled: i64 = 0
      while settled == 0 {
          let r: i64 = sys_wait4(pid, st, WNOHANG)
          if r == pid { settled = 1 }
          if settled == 0 {
              if (sys_now_ms() - t0) >= deadline_ms {
                  nx_kill(pid, SBR_SIGKILL)
                  sys_wait4(pid, st, 0)
                  sbr_puts("[nx_sov_build_run] COMPILE-TIMEOUT after " as *u8)
                  sbr_putn(deadline_ms)
                  sbr_puts("ms -- child pid " as *u8)
                  sbr_putn(pid)
                  sbr_puts(" (" as *u8)
                  sbr_puts(path)
                  sbr_puts(") was KILLED and reaped. THIS IS NOT A COMPILE FAILURE: the tool never\n" as *u8)
                  sbr_puts("  answered, so nothing was judged about your source. A hang and a rejection demand opposite\n" as *u8)
                  sbr_puts("  responses -- do NOT go looking for a syntax error until you have reproduced this bounded.\n" as *u8)
                  return SBR_TIMEOUT_RC
              }
              sys_sleep_ms(SBR_POLL_MS)
          }
      }
  }
  let sig: i64 = st[0] & 0x7f
  if sig != 0 { return 128 + sig }
  return sbr_exitcode(st[0])
333}
334
335// byte-size of a file (open, read in chunks, count) -- the determinism check for the empty-.s guard.
336func sbr_filesize(path: *u8) -> i64 {
  let fd: i64 = sys_openat_rd(path)
  if fd < 0 { return 0 }
  let buf: *u8 = sys_mmap(SBR_MAGIC_4096)
  var total: i64 = 0
  var n: i64 = sys_read(fd, buf, SBR_MAGIC_4096)
  while n > 0 { total = total + n; n = sys_read(fd, buf, SBR_MAGIC_4096) }
  sys_close(fd)
  return total
345}
346
347// ---- CONTENT-ADDRESSED BUILD CACHE (B2, 2026-08-17) --------------------------------------------------
348// The compiler is FAST (measured 80ms/gate) but re-emits the whole unchanged import closure every build.
349// This caches the FINAL .sov.elf keyed on a hash that covers EVERY compile input -- the fully-expanded
350// source closure (via nx_cc's OWN resolver expand_imports, composition not a second ruler), the compiler
351// AND assembler binaries, and the -g flag. A hit is byte-identical BY CONSTRUCTION: identical key => every
352// input identical => the deterministic toolchain emits identical bytes. FAIL-OPEN everywhere -- a miss,
353// an expand overflow, or any error just compiles normally, so the cache can only speed up, never break.
354// Toolchain targets are never cached (their own binary is in every key; a self-cache is meaningless).
355// COMPLETED 2026-08-23 (rung B2 of /compare/toolchain, watch symbol bld_cache_cas): the first cut stored
356// an entry by plain copy and served any entry that OPENED. That left three gaps the rung's own risk row
357// names: (1) a hit was never byte-verified, so a truncated or mid-write entry would be served as a HIT;
358// (2) the store was not atomic, so a concurrent reader could see a half-written elf; (3) a MISS was
359// SILENT, so "the cache missed" and "the cache is not there" were the same absence of output.
360// Now: every entry carries a SIDECAR (<key>.sov.elf.sha: sha256= bytes= key=) written AFTER the elf,
361// both via tmp+renameat; a hit is served ONLY after the cached bytes re-hash to the sidecar, and the
362// copy into _build/ is re-hashed too; every outcome prints ONE line, BUILD-CACHE HIT | MISS reason=<r>
363// | STORE, so a gate can assert on STATE (the .s the compiler writes is ABSENT on a hit) and a reader
364// can see which path ran. Kill switches: `cache_enabled=0` in ../knowledge/buildcache.conf (one parser
365// with cache_max_bytes) and the --no-cache lane flag. bld_cache_cas is the lookup+verify+serve entry;
366// bld_cache_cas_store the populate. Still fail-open on every error: the worst outcome is a compile.
367const SBR_CACHE_EXPAND_CAP: i64 = 33554432   // 32 MiB: biggest measured closure .s is ~9.2 MB (nx_browser);
                                           // expand_imports FAILS LOUD on overflow and we fail-open, so a
                                           // larger closure simply skips the cache -- safe, never wrong.
370
371// whole-file copy for cache <-> artifact. returns 0 ok, -1 fail (caller treats -1 as "no cache", fail-open).
372// COPY WHAT A COPY MEANS -- MODE IS PART OF THE FILE (2026-08-18). This copier opened its destination
373// 0644 for every byte it wrote, so a BUILD-CACHE HIT reproduced the artifact byte-perfect and INERT:
374// nx_sov_build_run removes the stale _build/<t>.sov.elf before every build, so the hit path always
375// CREATED the file fresh at 0644, and `nx_sov_build_run <t>` then ran it -> exit 127. Measured live
376// the day after B2 shipped (nx_vcodec_layout_gate: BUILD-CACHE HIT ... run-exit=127). B2's own proof
377// was byte identity -- structurally blind to mode, exactly the nx_filecopy defect banked 2026-08-14.
378// The fix is the same one nx_filecopy took: stat the SOURCE and apply ITS mode (st_mode is a u32 at
379// stat offset 24, the channel nx_offc_install proves), announcing UNKNOWN when it cannot stat rather
380// than silently leaving 0644. Every consumer inherits it: a nxasm-emitted 0755 artifact stored into
381// the cache is 0755 there, and a hit that copies it back is 0755 again -- no per-call-site chmod, one
382// mechanism.
383const SBR_STAT_MODE_OFF: i64 = 24
384const SBR_MODE_PERM_MASK: i64 = 511      // 0777: permission bits only; type bits never travel
385func sbr_src_mode(path: *u8) -> i64 {
  let sb: *u8 = sys_mmap(SBR_STATBUF)
  if sys_fstatat(path, sb) != 0 { sys_munmap(sb, SBR_STATBUF); return 0 - 1 }
  let m: i64 = (sb[SBR_STAT_MODE_OFF] as i64) + ((sb[SBR_STAT_MODE_OFF + 1] as i64) << 8)
  sys_munmap(sb, SBR_STATBUF)
  return m & SBR_MODE_PERM_MASK
391}
392// STAT-BASED SIZE. Returns -1 when the path is ABSENT and >=0 when it is present, so "gone" and "empty"
393// are two answers rather than one. sbr_filesize() below reads the whole file and returns 0 for BOTH -- an
394// absent-and-empty conflation that is harmless where it is used for a .s byte count and NOT harmless on the
395// one axis that matters here: the artifact a cache HIT claims to have delivered. st_size is the 64-bit field
396// at offset 48 of x86-64 struct stat; st_mode at offset 24 is the same buffer sbr_src_mode already proves,
397// so this opens no new syscall channel. Assembled top byte down, so no intermediate multiplier overflows.
398const SBR_STAT_SIZE_OFF: i64 = 48
399const SBR_STAT_SIZE_W:   i64 = 8
400func sbr_stat_size(path: *u8) -> i64 {
  let sb: *u8 = sys_mmap(SBR_STATBUF)
  if sys_fstatat(path, sb) != 0 { sys_munmap(sb, SBR_STATBUF); return 0 - 1 }
  var v: i64 = 0
  var i: i64 = SBR_STAT_SIZE_W - 1
  while i >= 0 {
      v = v * 256 + (sb[SBR_STAT_SIZE_OFF + i] as i64)
      i = i - 1
  }
  sys_munmap(sb, SBR_STATBUF)
  return v
411}
412func sbr_copyfile(srcp: *u8, dstp: *u8) -> i64 {
  let ln: *i64 = sys_mmap(16) as *i64
  ln[0] = 0
  let buf: *u8 = sys_read_file(srcp, ln)
  if (buf as i64) == 0 { sys_munmap(ln as *u8, 16); return 0 - 1 }
  let n: i64 = ln[0]
  let smode: i64 = sbr_src_mode(srcp)
  let fd: i64 = sys_openat_wr(dstp, 0x1a4)
  if fd < 0 { if n > 0 { sys_munmap(buf, n + 16) } sys_munmap(ln as *u8, 16); return 0 - 1 }
  var off: i64 = 0
  while off < n {
      let w: i64 = sys_write(fd, ((buf as i64) + off) as *u8, n - off)
      if w <= 0 { sys_close(fd); if n > 0 { sys_munmap(buf, n + 16) } sys_munmap(ln as *u8, 16); return 0 - 1 }
      off = off + w
  }
  sys_close(fd)
  if n > 0 { sys_munmap(buf, n + 16) }
  sys_munmap(ln as *u8, 16)
  // apply the source's permission bits AFTER the write (openat's mode is masked by umask and only
  // applies to a CREATED file; an existing destination keeps its old bits -- fchmodat sets both cases).
  if smode >= 0 { nx_chmod(dstp, smode) }
  if smode < 0 { sbr_puts("[nx_sov_build_run] copy: source mode UNKNOWN (stat failed) -- destination left at the create default\n" as *u8) }
  return 0
435}
436
437// 32-byte digest -> 64 lowercase hex chars at out (no NUL written). ONE encoder: sbr_cache_key and the
438// sidecar verify used to carry their own copy of this loop.
439func bld_cache_cas_hex(d: *u8, out: *u8) -> i64 {
  var i: i64 = 0
  while i < 32 {
      let v: i64 = d[i] as i64
      let hi: i64 = (v >> 4) & 15
      let lo: i64 = v & 15
      if hi < 10 { out[i*2] = (48+hi) as u8 } else { out[i*2] = (87+hi) as u8 }
      if lo < 10 { out[i*2+1] = (48+lo) as u8 } else { out[i*2+1] = (87+lo) as u8 }
      i = i + 1
  }
  return 0
450}
451
452// Compute the cache key hex (64 chars into out, null-terminated). Returns 0 on success, -1 fail-open.
453// Debug identity additionally binds the estate-relative root source path via bki_digest.
454// Release identity retains the content/toolchain/mode key for cross-path reuse.
455// THE INCUMBENT'S FLAVOUR, READ FROM ITS BYTES (2026-09-05, operator: "first byte fix"). A debug build carries the
456// DWARF section-name string .debug_line (nxasm writes it under -g; nx_contentdiff partitions exactly these runs as
457// lost_sectname); a release build carries no such run. Returns 1 = debug, 0 = release, -1 = unreadable / absent.
458// The needle is ASSEMBLED from two halves at runtime so THIS organ's own binary never holds it contiguously -- a
459// self-rebuild would otherwise read its own literal as evidence and default every runner build to debug (the
460// detector-counts-itself class, nx_gatelaw_gate 2026-09-03). sys_read_file sizes from the file: no cap, no short read.
461func sbr_incumbent_flavour(path: *u8) -> i64 {
  let ln: *i64 = sys_mmap(16) as *i64
  ln[0] = 0
  let buf: *u8 = sys_read_file(path, ln)
  if (buf as i64) == 0 { sys_munmap(ln as *u8, 16); return 0 - 1 }
  let n: i64 = ln[0]
  let needle: *u8 = sys_mmap(32); var no: i64 = 0
  no = sbr_cat(needle, no, ".debug_" as *u8); no = sbr_cat(needle, no, "line" as *u8); needle[no] = 0 as u8
  var found: i64 = 0
  var i: i64 = 0
  while found == 0 {
      if i + no > n { found = 0 - 1 } else {
          var j: i64 = 0
          var ok: i64 = 1
          while j < no {
              if buf[i + j] != needle[j] { ok = 0; j = no } else { j = j + 1 }
          }
          if ok == 1 { found = 1 }
          i = i + 1
      }
  }
  sys_munmap(needle, 32)
  sys_munmap(buf, n + 16)
  sys_munmap(ln as *u8, 16)
  if found == 1 { return 1 }
  return 0
487}
488
489func sbr_cache_key(src: *u8, compiler: *u8, asm_tool: *u8, want_debug: i64, out: *u8) -> i64 {
  let ebuf: *u8 = sys_mmap(SBR_CACHE_EXPAND_CAP)
  let ectx: *ExpandCtx = expand_ctx_new(ebuf, SBR_CACHE_EXPAND_CAP)
  let erc: i64 = expand_imports(ectx, src)
  if erc < 0 { sys_munmap(ebuf, SBR_CACHE_EXPAND_CAP); return 0 - 1 }
  expand_imports(ectx, "runtime/nx_crash.nx" as *u8)   // match nx_cc's default guard append (dedup-safe)
  let opp: *i64 = ectx.out_pos
  let elen: i64 = *opp
  let d0: *u8 = sys_mmap(48)
  sha256_digest(ebuf, elen, d0)
  let km: *u8 = sys_mmap(256)
  var kp: i64 = 0
  bld_cache_cas_hex(d0, km)
  kp = SBR_SHA_HEX
  if sbr_sha_hex(compiler, ((km as i64) + kp) as *u8) != 0 { sys_munmap(ebuf, SBR_CACHE_EXPAND_CAP); return 0 - 1 }
  kp = kp + SBR_SHA_HEX
  if sbr_sha_hex(asm_tool, ((km as i64) + kp) as *u8) != 0 { sys_munmap(ebuf, SBR_CACHE_EXPAND_CAP); return 0 - 1 }
  kp = kp + SBR_SHA_HEX
  if want_debug == 1 { km[kp] = 103 as u8 } else { km[kp] = 110 as u8 }   // 'g' | 'n'
  kp = kp + 1
  let dk: *u8 = sys_mmap(48)
  var logical_len: i64 = 0
  while src[logical_len] != (0 as u8) { logical_len = logical_len + 1 }
  if bki_digest(km, kp, want_debug, src, logical_len, dk) != 0 { sys_munmap(ebuf, SBR_CACHE_EXPAND_CAP); return 0 - 1 }
  bld_cache_cas_hex(dk, out)
  out[SBR_SHA_HEX] = 0 as u8
  sys_munmap(ebuf, SBR_CACHE_EXPAND_CAP)
  return 0
517}
518
519// ---- bld_cache_cas: the content-addressed LOOKUP + VERIFY + SERVE entry (rung B2 done-rule) ----------
520// Sidecar grammar (line-anchored, one field per line, order fixed):  sha256=<64 hex> NL bytes=<dec> NL key=<64 hex> NL
521// The sidecar is written AFTER the elf (both tmp+renameat), so "sidecar present" implies "elf complete".
522// Path widths DERIVED: cachepath is at most SBR_CACHE_PATHW (the prune census bound); the sidecar adds
523// ".sha" (4) and a tmp adds ".tmp-" (5) plus the target name, which argv bounds only by PATH_MAX -- so a
524// 4x slot is used and ANY overflow is announced and skipped (fail-open), never truncated.
525const SBR_CACHE_SIDE_SUFFIX: *u8 = ".sha"
526const SBR_CACHE_TMP_INFIX:   *u8 = ".tmp-"
527const SBR_CACHE_TMPW: i64 = 512      // 4 x SBR_CACHE_PATHW, see derivation above
528const SBR_CACHE_SIDE_MAX: i64 = 256  // sha256= (7+64) + bytes= (6+20 max i64 digits) + key= (4+64) + 3 NL = 168 < 256
529const SBR_CACHE_ELF_SUFFIX_LEN: i64 = 8   // ".sov.elf" -- the key is the SBR_SHA_HEX hex chars before it
530
531// first line of buf[0..n) that starts with `key`: copy the rest of that line (sans NL) into out[0..cap),
532// NUL-terminate, return its length; -1 when absent or longer than cap-1 (an over-long field is
533// malformed, not truncated-and-trusted).
534func bld_cache_cas_field(buf: *u8, n: i64, key: *u8, out: *u8, cap: i64) -> i64 {
  var klen: i64 = 0
  while key[klen] != (0 as u8) { klen = klen + 1 }
  var i: i64 = 0
  while i < n {
      var at_start: i64 = 0
      if i == 0 { at_start = 1 }
      if i > 0 { if buf[i-1] == (10 as u8) { at_start = 1 } }
      if at_start == 1 {
          var k: i64 = 0
          var hit: i64 = 1
          while k < klen {
              if i + k >= n { hit = 0; k = klen }
              if hit == 1 { if buf[i+k] != key[k] { hit = 0; k = klen } }
              if k < klen { k = k + 1 }
          }
          if hit == 1 {
              var j: i64 = i + klen
              var o: i64 = 0
              var scanning: i64 = 1
              while scanning == 1 {
                  if j >= n { scanning = 0 }
                  if scanning == 1 { if buf[j] == (10 as u8) { scanning = 0 } }
                  if scanning == 1 {
                      if o >= cap - 1 { return 0 - 1 }
                      out[o] = buf[j]; o = o + 1; j = j + 1
                  }
              }
              out[o] = 0 as u8
              return o
          }
      }
      i = i + 1
  }
  return 0 - 1
569}
570
571// Verify the entry at cachepath against its sidecar. 1 = verified (hex of the artifact's sha256 is left in
572// shaout, its size in *bytesout) | 0 = sha or size MISMATCH | -1 no entry | -2 sidecar absent | -3 sidecar
573// malformed. Reads the WHOLE artifact and re-hashes it every time: a hit that is not re-hashed is a hit
574// that trusts the disk, and the only reason to have a sidecar is not to.
575func bld_cache_cas_verify(cachepath: *u8, shaout: *u8, bytesout: *i64) -> i64 {
  let ce: i64 = sys_openat_rd(cachepath)
  if ce < 0 { return 0 - 1 }
  sys_close(ce)
  let side: *u8 = sys_mmap(SBR_CACHE_TMPW)
  var so: i64 = sbr_cat(side, 0, cachepath)
  so = sbr_cat(side, so, SBR_CACHE_SIDE_SUFFIX); side[so] = 0 as u8
  let sl: *i64 = sys_mmap(16) as *i64
  sl[0] = 0
  let sbuf: *u8 = sys_read_file(side, sl)
  if (sbuf as i64) == 0 { sys_munmap(side, SBR_CACHE_TMPW); sys_munmap(sl as *u8, 16); return 0 - 2 }
  let sn: i64 = sl[0]
  let want_sha: *u8 = sys_mmap(SBR_CACHE_SIDE_MAX)
  let want_bytes_s: *u8 = sys_mmap(SBR_CACHE_SIDE_MAX)
  let f1: i64 = bld_cache_cas_field(sbuf, sn, "sha256=" as *u8, want_sha, SBR_CACHE_SIDE_MAX)
  let f2: i64 = bld_cache_cas_field(sbuf, sn, "bytes=" as *u8, want_bytes_s, SBR_CACHE_SIDE_MAX)
  if sn > 0 { sys_munmap(sbuf, sn + 16) } else { sys_munmap(sbuf, SBR_EMPTY_RESERVE + 16) }
  sys_munmap(sl as *u8, 16)
  sys_munmap(side, SBR_CACHE_TMPW)
  if f1 != SBR_SHA_HEX { return 0 - 3 }
  if f2 <= 0 { return 0 - 3 }
  let want_bytes: i64 = sbr_atoi(want_bytes_s)
  if want_bytes < 0 { return 0 - 3 }
  if sbr_sha_hex(cachepath, shaout) != 0 { return 0 - 1 }
  // BY STAT, NOT BY WHOLE-FILE READ: sbr_filesize returns 0 for an ABSENT file, so an entry that vanished
  // between the open above and here would be reported as a size MISMATCH (which EVICTS) instead of as the
  // absence it is. -1 is routed to no-entry, the honest answer.
  let have_bytes: i64 = sbr_stat_size(cachepath)
  bytesout[0] = have_bytes
  if have_bytes < 0 { return 0 - 1 }
  if have_bytes != want_bytes { return 0 }
  var i: i64 = 0
  while i < SBR_SHA_HEX { if shaout[i] != want_sha[i] { return 0 } i = i + 1 }
  return 1
609}
610
611func bld_cache_cas_say(name: *u8, what: *u8, key: *u8) -> i64 {
  sbr_puts("[nx_sov_build_run] " as *u8); sbr_puts(name); sbr_puts(": BUILD-CACHE " as *u8); sbr_puts(what)
  if key != (0 as *u8) { sbr_puts(" key=" as *u8); sbr_puts(key) }
  return 0
615}
616func bld_cache_cas_nl() -> i64 { let b: *u8 = sys_mmap(2); b[0] = 10 as u8; sys_write(1, b, 1); sys_munmap(b, 2); return 0 }
617
618// THE ENTRY. Returns 1 on a verified HIT (elfpath now holds the byte-identical artifact, mode preserved),
619// 0 on any MISS -- and prints exactly one BUILD-CACHE line either way, naming the reason on a miss.
620// sha-mismatch EVICTS the entry and its sidecar (a corrupt entry must not be offered twice); every other
621// miss leaves the store alone so a concurrent populate in flight is never destroyed.
622func bld_cache_cas(cachekey: *u8, cachepath: *u8, elfpath: *u8, name: *u8) -> i64 {
  let sha: *u8 = sys_mmap(SBR_SHA_HEX + 2)
  let bp: *i64 = sys_mmap(16) as *i64
  bp[0] = 0
  let v: i64 = bld_cache_cas_verify(cachepath, sha, bp)
  if v == 0 - 1 { bld_cache_cas_say(name, "MISS reason=no-entry" as *u8, cachekey); bld_cache_cas_nl(); return 0 }
  if v == 0 - 2 { bld_cache_cas_say(name, "MISS reason=sidecar-absent" as *u8, cachekey); bld_cache_cas_nl(); return 0 }
  if v == 0 - 3 { bld_cache_cas_say(name, "MISS reason=sidecar-malformed" as *u8, cachekey); bld_cache_cas_nl(); return 0 }
  if v == 0 {
      let side: *u8 = sys_mmap(SBR_CACHE_TMPW)
      var so: i64 = sbr_cat(side, 0, cachepath)
      so = sbr_cat(side, so, SBR_CACHE_SIDE_SUFFIX); side[so] = 0 as u8
      sys_unlinkat(cachepath)
      sys_unlinkat(side)
      bld_cache_cas_say(name, "MISS reason=sha-mismatch (entry EVICTED: cached bytes do not re-hash to their sidecar)" as *u8, cachekey)
      bld_cache_cas_nl()
      return 0
  }
  if sbr_copyfile(cachepath, elfpath) != 0 { bld_cache_cas_say(name, "MISS reason=copy-failed" as *u8, cachekey); bld_cache_cas_nl(); return 0 }
  // the COPY is re-hashed too: a short write into _build/ would otherwise be a verified hit of the wrong bytes
  let sha2: *u8 = sys_mmap(SBR_SHA_HEX + 2)
  if sbr_sha_hex(elfpath, sha2) != 0 { bld_cache_cas_say(name, "MISS reason=copy-failed" as *u8, cachekey); bld_cache_cas_nl(); return 0 }
  var i: i64 = 0
  while i < SBR_SHA_HEX {
      if sha[i] != sha2[i] { sys_unlinkat(elfpath); bld_cache_cas_say(name, "MISS reason=copy-failed (copy does not re-hash)" as *u8, cachekey); bld_cache_cas_nl(); return 0 }
      i = i + 1
  }
  // ---- THE ARTIFACT ASSERTION (2026-09-04, LANE-D root fix) ------------------------------------
  // A CACHE THAT VERIFIES A SIDECAR WITHOUT STAT-ING THE FILE THE SIDECAR DESCRIBES IS ASSERTING A
  // PROPERTY OF AN ARTIFACT IT NEVER LOOKED AT. Everything above this line judges the CACHE ENTRY and
  // the COPY OPERATION. Nothing judged the DELIVERED FILE -- so "byte-identical artifact reused" was an
  // invariant EMERGING from three helpers agreeing, never an asserted fact, and the builder had no
  // vocabulary in which to report its failure. MEASURED 2026-09-04 on a copy of this builder with the
  // copy-back chain removed: it printed BUILD-CACHE HIT ... byte-identical artifact reused, exited 0,
  // and left NO FILE; every downstream consumer then failed against an artifact announced as reused.
  // This stat is the only check whose SUBJECT is the delivered artifact rather than the operation that
  // was supposed to produce it, which is exactly why it survives the removal of that operation.
  // FAIL DIRECTION IS A MISS, NEVER AN ERROR: returning 0 sends the build down the compile path, so the
  // worst outcome of this check is one compile -- the same fail-open contract the rest of this cache keeps.
  let delivered: i64 = sbr_stat_size(elfpath)
  if delivered != bp[0] {
      sys_unlinkat(elfpath)
      bld_cache_cas_say(name, "MISS reason=artifact-not-materialised (a HIT was verified but the artifact is not on disk: stat says " as *u8, 0 as *u8)
      if delivered < 0 { sbr_puts("ABSENT" as *u8) }
      if delivered >= 0 { sbr_putn(delivered); sbr_puts(" bytes" as *u8) }
      sbr_puts(", the verified entry is " as *u8); sbr_putn(bp[0])
      sbr_puts(" bytes. NOT claiming reuse; compiling instead)" as *u8)
      bld_cache_cas_nl()
      return 0
  }
  bld_cache_cas_say(name, "HIT" as *u8, cachekey)
  sbr_puts(" bytes=" as *u8); sbr_putn(bp[0]); sbr_puts(" sha256=" as *u8); sbr_puts(sha)
  sbr_puts(" -- verified against its sidecar, byte-identical artifact reused, compiler NOT run" as *u8)
  bld_cache_cas_nl()
  return 1
677}
678
679// POPULATE after a real build: elf via tmp+renameat, THEN sidecar via tmp+renameat (ordering is the
680// contract bld_cache_cas_verify relies on). Announces STORE / STORE-FAILED reason=. Fail-open.
681func bld_cache_cas_store(elfpath: *u8, cachepath: *u8, name: *u8) -> i64 {
  var plen: i64 = 0
  while cachepath[plen] != (0 as u8) { plen = plen + 1 }
  var nlen: i64 = 0
  while name[nlen] != (0 as u8) { nlen = nlen + 1 }
  if plen + 4 + 5 + nlen + 1 >= SBR_CACHE_TMPW {
      bld_cache_cas_say(name, "STORE-FAILED reason=path-too-long (not truncated; entry skipped)" as *u8, 0 as *u8); bld_cache_cas_nl()
      return 0 - 1
  }
  let tmp: *u8 = sys_mmap(SBR_CACHE_TMPW)
  var t: i64 = sbr_cat(tmp, 0, cachepath)
  t = sbr_cat(tmp, t, SBR_CACHE_TMP_INFIX); t = sbr_cat(tmp, t, name); tmp[t] = 0 as u8
  if sbr_copyfile(elfpath, tmp) != 0 { sys_unlinkat(tmp); bld_cache_cas_say(name, "STORE-FAILED reason=copy" as *u8, 0 as *u8); bld_cache_cas_nl(); return 0 - 1 }
  let sha: *u8 = sys_mmap(SBR_SHA_HEX + 2)
  if sbr_sha_hex(tmp, sha) != 0 { sys_unlinkat(tmp); bld_cache_cas_say(name, "STORE-FAILED reason=hash" as *u8, 0 as *u8); bld_cache_cas_nl(); return 0 - 1 }
  // SAME LAW, STORE SIDE: the sidecar is a claim ABOUT the staged entry, so size it by stat and refuse
  // to write a sidecar describing a file that is not there (sbr_filesize would have recorded bytes=0 and
  // produced an entry that self-evicts as sha-mismatch forever after).
  let nbytes: i64 = sbr_stat_size(tmp)
  if nbytes < 0 {
      sys_unlinkat(tmp)
      bld_cache_cas_say(name, "STORE-FAILED reason=staged-entry-absent (refusing to write a sidecar describing a file that is not there)" as *u8, 0 as *u8)
      bld_cache_cas_nl()
      return 0 - 1
  }
  if sys_renameat(tmp, cachepath) != 0 { sys_unlinkat(tmp); bld_cache_cas_say(name, "STORE-FAILED reason=rename" as *u8, 0 as *u8); bld_cache_cas_nl(); return 0 - 1 }
  // sidecar: build the text, write to tmp, rename over <cachepath>.sha
  let side: *u8 = sys_mmap(SBR_CACHE_TMPW)
  var so: i64 = sbr_cat(side, 0, cachepath)
  so = sbr_cat(side, so, SBR_CACHE_SIDE_SUFFIX); side[so] = 0 as u8
  let stmp: *u8 = sys_mmap(SBR_CACHE_TMPW)
  var st: i64 = sbr_cat(stmp, 0, side)
  st = sbr_cat(stmp, st, SBR_CACHE_TMP_INFIX); st = sbr_cat(stmp, st, name); stmp[st] = 0 as u8
  let txt: *u8 = sys_mmap(SBR_CACHE_SIDE_MAX)
  var x: i64 = sbr_cat(txt, 0, "sha256=" as *u8); x = sbr_cat(txt, x, sha); txt[x] = 10 as u8; x = x + 1
  x = sbr_cat(txt, x, "bytes=" as *u8)
  x = nxi_buf(txt, x, nbytes)      // digits only, returns the offset after them (nx_itoa_lib contract)
  txt[x] = 10 as u8; x = x + 1
  // key= is the basename of cachepath between "_build/cache/" and ".sov.elf" -- written so a sidecar
  // found out of place still says which key it belongs to; the reader does not depend on it.
  x = sbr_cat(txt, x, "key=" as *u8)
  var kb: i64 = plen - SBR_CACHE_ELF_SUFFIX_LEN - SBR_SHA_HEX
  if kb < 0 { kb = 0 }
  var ki: i64 = 0
  while ki < SBR_SHA_HEX { if kb + ki < plen { txt[x] = cachepath[kb + ki]; x = x + 1 } ki = ki + 1 }
  txt[x] = 10 as u8; x = x + 1
  let sfd: i64 = sys_openat_wr(stmp, 0x1a4)
  if sfd < 0 { bld_cache_cas_say(name, "STORE-FAILED reason=sidecar-open" as *u8, 0 as *u8); bld_cache_cas_nl(); return 0 - 1 }
  var woff: i64 = 0
  while woff < x {
      let w: i64 = sys_write(sfd, ((txt as i64) + woff) as *u8, x - woff)
      if w <= 0 { sys_close(sfd); sys_unlinkat(stmp); bld_cache_cas_say(name, "STORE-FAILED reason=sidecar-write" as *u8, 0 as *u8); bld_cache_cas_nl(); return 0 - 1 }
      woff = woff + w
  }
  sys_close(sfd)
  if sys_renameat(stmp, side) != 0 { sys_unlinkat(stmp); bld_cache_cas_say(name, "STORE-FAILED reason=sidecar-rename" as *u8, 0 as *u8); bld_cache_cas_nl(); return 0 - 1 }
  bld_cache_cas_say(name, "STORE" as *u8, 0 as *u8)
  sbr_puts(" bytes=" as *u8); sbr_putn(nbytes); sbr_puts(" sha256=" as *u8); sbr_puts(sha)
  bld_cache_cas_nl()
  return 0
741}
742
743// ---- BUILD-CACHE BYTE BUDGET (2026-08-18) -- the cap owed since B2 shipped ---------------------
744// One elf per distinct (closure, toolchain, flags) forever is an unbounded append-only store, and a
745// compiler promote orphans an entire key generation at once (measured the day B1 DCE shipped: all
746// 121 entries dead in one promote). The estate's remedy for an unbounded store is a LOUD budget --
747// and for a CACHE, eviction is additionally safe by construction: every entry is regenerable from
748// source, so a wrong eviction costs one compile, never data.
749// THE BUDGET IS DATA (rules 11+17): ../knowledge/buildcache.conf key cache_max_bytes overrides the
750// default without a rebuild. THE DEFAULT IS DERIVED, NOT TASTE: 13,202 buildable sources x ~45 KB
751// mean post-DCE elf (558 MB over 12,336 built, measured in the B1 full-population sweep) is ~600 MB
752// for one full compiler generation; the budget must hold one generation plus churn or the daily
753// drift census would thrash its own hits. 1 GiB covers that with headroom on the volume.
754// EVICTION IS OLDEST-mtime-FIRST. Documented imprecision: a HIT does not refresh mtime, so mtime is
755// store order, not use order -- a hot entry can be evicted and costs one re-compile on its next
756// miss. Chosen because touching on hit would put a write on the fast path this cache exists to keep
757// read-only.
758const SBR_CACHE_BUDGET_DEFAULT: i64 = 1073741824
759const SBR_CACHE_DIRBUF: i64 = 65536
760// enumeration pool bound. NOT a silent cap: overflow ANNOUNCES and skips the prune entirely (the
761// cache keeps working; only its janitor abstains), because pruning from a partial listing would
762// evict by an incomplete ordering. 32768 slots is 2.5x the whole estate's source count.
763const SBR_CACHE_PRUNE_SLOTS: i64 = 32768
764// Path slot width, DERIVED not hand-counted (the first cut of this constant was 80 and silently
765// truncated every real entry -- "_build/cache/" is 13 bytes, the key is a 64-hex sha256, ".sov.elf"
766// is 8, plus the NUL = 86 -- so the census dropped the very entries it was sizing and the budget
767// never tripped; caught by strace showing an open of "....s"). 128 = the derivation rounded up to
768// a power of two; anything that still does not fit is SKIPPED AND ANNOUNCED, never truncated.
769const SBR_CACHE_PATHW: i64 = 128
770
771// Read one `<key>=<decimal>` row from ../knowledge/buildcache.conf; absent/unreadable/non-numeric -> dflt.
772// ONE parser for every cache conf row (cache_max_bytes, cache_enabled): the second row to need it is the
773// signal it was a shared primitive, not a second copy of the loop.
774func sbr_cache_conf_int(key: *u8, dflt: i64) -> i64 {
  let lenp: *i64 = sys_mmap(16) as *i64
  let cf: *u8 = sys_read_file("../knowledge/buildcache.conf" as *u8, lenp)
  if (cf as i64) == 0 { return dflt }
  let n: i64 = lenp[0]
  var klen: i64 = 0
  while key[klen] != (0 as u8) { klen = klen + 1 }
  var i: i64 = 0
  while i < n {
      var at_start: i64 = 0
      if i == 0 { at_start = 1 }
      if i > 0 { if cf[i-1] == (10 as u8) { at_start = 1 } }
      if at_start == 1 {
          var k: i64 = 0
          var hit: i64 = 1
          while k < klen {
              if i + k >= n { hit = 0; k = klen }
              if hit == 1 { if cf[i+k] != key[k] { hit = 0; k = klen } }
              if k < klen { k = k + 1 }
          }
          if hit == 1 {
              var v: i64 = 0
              var got: i64 = 0
              var j: i64 = i + klen
              var scanning: i64 = 1
              while scanning == 1 {
                  if j >= n { scanning = 0 }
                  if scanning == 1 {
                      let c: i64 = cf[j] as i64
                      var isdig: i64 = 0
                      if c >= 48 { if c <= 57 { isdig = 1 } }
                      if isdig == 1 { v = v * 10 + (c - 48); got = 1; j = j + 1 }
                      if isdig == 0 { scanning = 0 }
                  }
              }
              if got == 1 { return v }
          }
      }
      i = i + 1
  }
  return dflt
815}
816// cache_max_bytes: nonpositive is not a budget -> default (the conf cannot switch the janitor off by 0).
817func sbr_cache_budget() -> i64 {
  let v: i64 = sbr_cache_conf_int("cache_max_bytes=" as *u8, SBR_CACHE_BUDGET_DEFAULT)
  if v <= 0 { return SBR_CACHE_BUDGET_DEFAULT }
  return v
821}
822// cache_enabled: 0 disables lookup AND store without a rebuild; any other value (or no row) = enabled.
823func sbr_cache_enabled() -> i64 {
  let v: i64 = sbr_cache_conf_int("cache_enabled=" as *u8, 1)
  if v == 0 { return 0 }
  return 1
827}
828
829// Enforce the byte budget on _build/cache. Called ONLY after a successful store, so its cost rides
830// the slow path (a real compile just happened; one directory walk is noise beside it) and never the
831// hit path. Fail-open at every step: a janitor that cannot run must never break a build.
832func sbr_cache_prune() -> i64 {
  let budget: i64 = sbr_cache_budget()
  let dfd: i64 = __syscall(257, 0-100, "_build/cache" as *u8 as i64, 0x10000, 0, 0, 0)
  if dfd < 0 { return 0 }
  let mt: *i64 = sys_mmap(SBR_CACHE_PRUNE_SLOTS * 8) as *i64
  let sz: *i64 = sys_mmap(SBR_CACHE_PRUNE_SLOTS * 8) as *i64
  let no: *i64 = sys_mmap(SBR_CACHE_PRUNE_SLOTS * 8) as *i64
  let arena: *u8 = sys_mmap(SBR_CACHE_PRUNE_SLOTS * SBR_CACHE_PATHW)
  var ap: i64 = 0
  var ne: i64 = 0
  var overflow: i64 = 0
  var total: i64 = 0
  let dbuf: *u8 = sys_mmap(SBR_CACHE_DIRBUF)
  var more: i64 = 1
  while more == 1 {
      let nb: i64 = sys_getdents64(dfd, dbuf, SBR_CACHE_DIRBUF)
      if nb <= 0 { more = 0 } else {
          var p: i64 = 0
          while p < nb {
              let reclen: i64 = (dbuf[p+16] as i64) + ((dbuf[p+17] as i64) * 256)
              if reclen <= 0 { p = nb } else {
                  let nmp: *u8 = ((dbuf as i64) + p + 19) as *u8
                  var isdot: i64 = 0
                  if nmp[0] == (46 as u8) { if nmp[1] == (0 as u8) { isdot = 1 } }
                  if nmp[0] == (46 as u8) { if nmp[1] == (46 as u8) { if nmp[2] == (0 as u8) { isdot = 1 } } }
                  if isdot == 0 {
                      if ne >= SBR_CACHE_PRUNE_SLOTS { overflow = 1 }
                      if overflow == 0 {
                          let path: *u8 = ((arena as i64) + ap) as *u8
                          var q: i64 = 0
                          q = sbr_cat(path, q, "_build/cache/" as *u8)
                          var c: i64 = 0
                          var toolong: i64 = 0
                          while nmp[c] != (0 as u8) {
                              if q < SBR_CACHE_PATHW - 1 { path[q] = nmp[c]; q = q + 1 }
                              if q >= SBR_CACHE_PATHW - 1 { toolong = 1 }
                              c = c + 1
                          }
                          path[q] = 0 as u8
                          if toolong == 1 {
                              sbr_puts("[nx_sov_build_run] BUILD-CACHE-PRUNE SKIP-ENTRY: name exceeds the path slot (SBR_CACHE_PATHW) -- counted out of the census rather than stat'd through a truncated path
873" as *u8)
                          }
                          var fsz: i64 = 0 - 1
                          var fmt: i64 = 0 - 1
                          if toolong == 0 { fsz = sbr_filesize(path) }
                          if toolong == 0 { fmt = sbr_mtime(path) }
                          if fsz >= 0 { if fmt >= 0 {
                              mt[ne] = fmt
                              sz[ne] = fsz
                              no[ne] = ap
                              total = total + fsz
                              ne = ne + 1
                              ap = ap + SBR_CACHE_PATHW
                          } }
                      }
                  }
                  p = p + reclen
              }
          }
      }
  }
  sys_close(dfd)
  if overflow == 1 {
      sbr_puts("[nx_sov_build_run] BUILD-CACHE-PRUNE SKIPPED: more entries than the enumeration pool (SBR_CACHE_PRUNE_SLOTS) -- pruning from a partial listing would evict by an incomplete ordering. Raise the pool or prune by hand.\n" as *u8)
      return 0
  }
  if total <= budget { return 0 }
  var evicted: i64 = 0
  var freed: i64 = 0
  var draining: i64 = 1
  while draining == 1 {
      if total <= budget { draining = 0 }
      if draining == 1 {
          var oldest: i64 = 0 - 1
          var oldmt: i64 = 0
          var i2: i64 = 0
          while i2 < ne {
              if sz[i2] >= 0 {
                  if oldest < 0 { oldest = i2; oldmt = mt[i2] }
                  if mt[i2] < oldmt { oldest = i2; oldmt = mt[i2] }
              }
              i2 = i2 + 1
          }
          if oldest < 0 { draining = 0 }
          if oldest >= 0 {
              let vp: *u8 = ((arena as i64) + no[oldest]) as *u8
              if sys_unlinkat(vp) == 0 {
                  total = total - sz[oldest]
                  freed = freed + sz[oldest]
                  evicted = evicted + 1
              }
              sz[oldest] = 0 - 1
          }
      }
  }
  if evicted > 0 {
      sbr_puts("[nx_sov_build_run] BUILD-CACHE-PRUNE evicted=" as *u8); sbr_putn(evicted)
      sbr_puts(" freed=" as *u8); sbr_putn(freed)
      sbr_puts("B budget=" as *u8); sbr_putn(budget)
      sbr_puts("B kept=" as *u8); sbr_putn(ne - evicted)
      sbr_puts(" (oldest-mtime-first; every entry regenerable by one compile)\n" as *u8)
  }
  return evicted
936}
937
938func main(argc: i64, argv: *i64) -> i64 {
  if argc < 2 { sbr_puts("usage: nx_sov_build_run <module-basename> [--build-only] [--install] [--debug] [args-forwarded-to-program...]  (--debug passes -g to nx_cc so the ELF carries .debug_line and nx_addr2line can name the faulting source line; lane flags may be combined)\n" as *u8); sys_exit(SBR_USAGE); return SBR_USAGE }
  let name: *u8 = argv[1] as *u8
941
  // ---- ANCHOR THE CWD 2026-08-07 -------------------------------------------------------------
  // EVERY path in this runner is relative to the build tree root: the source probes, the toolchain
  // (_build/nx_cc_sovereign.elf), the admission binary, ../knowledge/tree_canon.conf, and -- decisively
  // -- nx_cc's OWN import resolution for `import "nx_syscalls.nx"`. That is correct only when CWD is
  // already the tree, which holds when a human runs it from buildroot/ and fails for every other
  // caller: nx_job_run, the supervisor and any operator all start in the SERVING ROOT, where the same
  // tree sits one level down under buildroot/.
  // The first attempt at this added buildroot/ prefixes to the source probe. It moved the failure
  // exactly one step -- SOURCE-NOT-FOUND became "BUILD ADMISSION DID NOT RUN (rc=127)", "TREE-CANON
  // NOT CHECKED: ../knowledge/tree_canon.conf absent", then COMPILE-FAIL with an EMPTY .s and EMPTY
  // stderr, because the compiler could not resolve the imports either. Prefixing one path fixed one
  // path, and there were five.
  // WHEN EVERY PATH IN A PROGRAM IS RELATIVE TO ONE DIRECTORY, THE FIX IS TO BE IN THAT DIRECTORY,
  // NOT TO PREFIX EVERY PATH -- and the prefix version is worse than nothing, because it converts a
  // loud SOURCE-NOT-FOUND into two silent PROCEEDING-UNGUARDED warnings and a misleading compile
  // error. IT DISARMED TWO GUARDS TO REACH A FAILURE.
  // Detect, do not assume: only chdir when runtime/ is genuinely absent here AND present under
  // buildroot/, so a correct invocation from the tree root is completely unaffected.
  // PROBE A LOAD-BEARING FILE, NOT A DIRECTORY NAME. The first version of this probe asked whether
  // runtime/_hdl_build EXISTED and was satisfied by a NINE-FILE scratch directory sitting in the
  // serving root beside the real 6,992-file tree in buildroot/. So the anchor never fired, and worse:
  // left alone, this runner resolves runtime/_hdl_build/<name>.nx against that scratch dir and would
  // compile a DIFFERENT tree from the one /api/build builds -- a forked copy reported as success,
  // which is precisely what the tree-canon admission exists to prevent and which canon cannot see,
  // because canon compares the laptop against buildroot and has never heard of this third directory.
  // A DIRECTORY WITH THE RIGHT NAME IS NOT THE TREE; PROBE SOMETHING THE TREE CANNOT LACK.
  // runtime/nx_syscalls.nx is imported by essentially every organ, so its presence identifies the
  // real tree and its absence rules out any partial look-alike.
  // ★ROOT FIX 2026-08-07 -- WHERE `_offc/` POINTS DEPENDS ON WHETHER WE ANCHORED.
  // Everything below resolves `_offc/<name>.elf` relative to the CWD.  When the anchor fires we are
  // INSIDE buildroot/, so that path is buildroot/_offc/ -- a 106-file SHADOW of the serving root's
  // 340-file _offc/, which is the one gates and organs actually fork.  Two consequences, both
  // MEASURED 2026-08-07:
  //   (1) --install printed "INSTALLED -> _offc/<name>.elf" and the consumer's copy was untouched.
  //       THE SUCCESS WORD WAS TRUE ABOUT THE COPY AND WRONG ABOUT THE DESTINATION.
  //   (2) Worse, LM-026's refresh-IF-PRESENT decides `do_install` by testing whether that same
  //       shadow path exists -- so for every organ whose twin lives in the SERVING _offc/, the
  //       probe missed, do_install stayed 0, and the rebuild silently did not reach the consumer.
  //       The staleness LM-026 was written to retire has been surviving its own fix.
  // This prefix makes both the probe and the install name the directory consumers read.  It is also
  // why the toolchain incident this file records could happen at all: buildroot/_offc is REACHABLE,
  // not inert, so writing there is not a harmless no-op -- it plants a shadow.
  var offc_pfx: *u8 = "_offc/" as *u8
  // ★ROOT FIX 2026-08-07 (second deploy location).  THE ESTATE HAS TWO CONSUMER DIRECTORIES, and
  // refresh-IF-PRESENT only ever knew about one.  MEASURED: 1,652 .elf are served from the SERVING
  // ROOT and only 110 from _offc/ -- and 1,551 organs have a ROOT twin with a source but NO _offc
  // twin, so for 94% of everything deployed the LM-026 probe missed, do_install stayed 0, and a
  // successful rebuild never reached the consumer.  That is the estate's "1,557 deployed / 6
  // CURRENT" adoption gap, and this line is its mechanism.
  // A REFRESH THAT KNOWS ONE OF THE TWO PLACES ITS CONSUMERS READ IS BLIND TO MOST OF THEM.
  var root_pfx: *u8 = "" as *u8
  let probe_here: i64 = sys_openat_rd("runtime/nx_syscalls.nx" as *u8)
  if probe_here < 0 {
      let probe_br: i64 = sys_openat_rd("buildroot/runtime/nx_syscalls.nx" as *u8)
      if probe_br >= 0 {
          sys_close(probe_br)
          sys_chdir("buildroot" as *u8)
          offc_pfx = "../_offc/" as *u8   // we are now inside buildroot/; the consumers' _offc is one level up
          root_pfx = "../" as *u8         // ...and the serving root, where 1,551 organs actually live
          sbr_puts("[nx_sov_build_run] CWD anchored to buildroot/ (started in the serving root)\
1002" as *u8)
      }
  }
  if probe_here >= 0 { sys_close(probe_here) }
1006
  // FLAGS (argv[2]): --build-only (--b*) = skip the run; --install (--i*) = FORCE-install /tmp/<name>.sov.elf
  // to _offc/<name>.elf even with NO existing twin (makes a reusable TOOL permanent on first build) + skip run.
  // Default = refresh-IF-PRESENT (LM-026) + run. Opt-in so throwaway gates/probes never clutter _offc.
  // Everything AFTER the optional flag is FORWARDED to the built program (fwd_start below).
  var force_install: i64 = 0
  var skip_run: i64 = 0
  // --build-only MUST MEAN BUILD ONLY (2026-08-26). Tracked SEPARATELY from skip_run because --install
  // also skips the run yet is an explicit, deliberate request TO install -- so skip_run cannot carry
  // this meaning. nx_builddeploy_lib owns the resulting decision.
  var build_only: i64 = 0
  var want_debug: i64 = 0
  var want_release: i64 = 0
  var fwd_start: i64 = 2
  // LANE FLAGS ARE A LOOP, NOT A SLOT (2026-08-15). This read argv[2] ONLY, so a SECOND lane flag was
  // silently FORWARDED TO THE BUILT PROGRAM instead of consumed: `--build-only --debug` would have
  // compiled WITHOUT debug and passed "--debug" to the target as a program argument. One slot is not a
  // parser, and the defect is invisible because both halves succeed at something.
  // A lane flag is recognised by its '--' prefix; the first non-flag argument ends the lane's section
  // and everything from there is forwarded. With no flags fwd_start stays 2, so the default path is
  // byte-identical to the single-slot version it replaces.
  // --timeout-ms <n> overrides the build deadline. It keys on 't' because --debug already owns 'd',
  // and it is the ONLY lane flag that CONSUMES A VALUE -- hence `extra`, since advancing by one
  // would forward the number to the built program as an argument (the exact single-slot defect the
  // comment above records).
  var deadline_ms: i64 = SBR_BUILD_DEADLINE_MS
  var no_cache: i64 = 0
  var fi: i64 = 2
  var scanning: i64 = 1
  while scanning == 1 {
      if fi >= argc { scanning = 0 } else {
          let fl: *u8 = argv[fi] as *u8
          if fl[0] != (45 as u8) { scanning = 0 } else {
              if fl[1] != (45 as u8) { scanning = 0 } else {
                  var extra: i64 = 0
                  if fl[2] == (98 as u8) { skip_run = 1; build_only = 1 }       // --build-only
                  if fl[2] == (105 as u8) { force_install = 1; skip_run = 1 }   // --install
                  if fl[2] == (100 as u8) { want_debug = 1 }                    // --debug -> -g to nx_cc
                  if fl[2] == (110 as u8) { no_cache = 1 }                      // --no-cache: skip the B2 lookup AND store
                  if fl[2] == (114 as u8) { want_release = 1 }                  // --release -> a release build even when the incumbent is debug (announced below)
                  if fl[2] == (116 as u8) {                                     // --timeout-ms <n>
                      if (fi + 1) >= argc {
                          sbr_puts("[nx_sov_build_run] REFUSED: --timeout-ms needs a value in milliseconds.\n" as *u8)
                          sys_exit(SBR_USAGE); return SBR_USAGE
                      }
                      let dv: i64 = sbr_atoi(argv[fi + 1] as *u8)
                      if dv < 0 {
                          sbr_puts("[nx_sov_build_run] REFUSED: --timeout-ms value must be a plain decimal count of milliseconds.\n" as *u8)
                          sys_exit(SBR_USAGE); return SBR_USAGE
                      }
                      deadline_ms = dv
                      extra = 1
                  }
                  fi = fi + 1 + extra
                  fwd_start = fi
              }
          }
      }
  }
  // THE FLAVOUR FOLLOWS THE INCUMBENT (2026-09-05, operator: "first byte fix"). A build's debug/release flavour used to be
  // a per-call flag nobody declares per target, so a rebuild that omitted --debug silently produced the OTHER flavour of
  // the live binary and /api/promote then read the swap as CAPLOSS 422 permil (nx_wgsl: 823 lost runs, every one a source
  // path, a symbol name or a DWARF section name, lost_other=0). A seat then either rebuilt or passed allow_capability_loss
  // and disarmed the one guard that catches a real regression. Now, with neither --debug nor --release given, the flavour
  // is READ FROM THE INCUMBENT'S BYTES (root_pfx + name + .elf, the serving-root twin this runner holds or refreshes):
  // the DWARF line-table section name present = debug. No incumbent = release, the historical default. Every path
  // ANNOUNCES flavour= and src= so a reader can tell a derived flavour from a declared one; --release is the explicit
  // switch. The announce strings deliberately never spell the section name contiguously (sbr_incumbent_flavour's note).
  var flavour_src: *u8 = "argv --debug" as *u8
  if want_release == 1 { want_debug = 0; flavour_src = "argv --release" as *u8 }
  if want_release == 0 {
      if want_debug == 0 {
          let incp: *u8 = sys_mmap(256); var io: i64 = 0
          io = sbr_cat(incp, io, root_pfx); io = sbr_cat(incp, io, name); io = sbr_cat(incp, io, ".elf" as *u8); incp[io] = 0 as u8
          let ifl: i64 = sbr_incumbent_flavour(incp)
          if ifl == 1 { want_debug = 1; flavour_src = "incumbent (the serving-root twin carries a DWARF line table)" as *u8 }
          if ifl == 0 { flavour_src = "incumbent (the serving-root twin carries no DWARF line table)" as *u8 }
          if ifl < 0 { flavour_src = "default (no incumbent to read)" as *u8 }
          sys_munmap(incp, 256)
      }
  }
  sbr_puts("[nx_sov_build_run] FLAVOUR " as *u8)
  if want_debug == 1 { sbr_puts("debug" as *u8) } else { sbr_puts("release" as *u8) }
  sbr_puts(" src=" as *u8); sbr_puts(flavour_src); sbr_puts("\n" as *u8)
  // ANNOUNCE THE FEATURE, NOT ONLY ITS FAILURE (the 2026-08-07 law): if this line is absent when
  // --debug was passed, the FLAG PARSE missed it -- which is otherwise indistinguishable from the
  // compiler ignoring -g, and those have opposite remedies.
  if want_debug == 1 { sbr_puts("[nx_sov_build_run] DEBUG BUILD: -g -> nx_cc emits .file/.loc -> nxasm builds .debug_line -> nx_addr2line resolves a fault address to file:line.\n" as *u8) }
  // ANNOUNCE A NON-DEFAULT BOUND (same law as --debug above). Deliberately SILENT on the default so
  // the ordinary build's output stays byte-identical for anything that parses it -- a safety line
  // that regresses every caller's log is not safety. An UNBOUNDED deadline always announces.
  if deadline_ms != SBR_BUILD_DEADLINE_MS {
      sbr_puts("[nx_sov_build_run] build deadline OVERRIDDEN to " as *u8); sbr_putn(deadline_ms)
      if deadline_ms <= 0 { sbr_puts("ms = UNBOUNDED: a hanging tool will burn a core until a human notices.\n" as *u8) }
      if deadline_ms > 0 { sbr_puts("ms per compile/assemble step.\n" as *u8) }
  }
1102
  let src: *u8 = sys_mmap(512); var o: i64 = 0
  o = sbr_cat(src, o, "runtime/_hdl_build/" as *u8); o = sbr_cat(src, o, name); o = sbr_cat(src, o, ".nx" as *u8); src[o] = 0 as u8
  // fall back to runtime/<name>.nx if the module isn't under _hdl_build (additive; the older slice stack lives in runtime/)
  let chk: i64 = sys_openat_rd(src)
  if chk < 0 {
      o = 0
      o = sbr_cat(src, o, "runtime/" as *u8); o = sbr_cat(src, o, name); o = sbr_cat(src, o, ".nx" as *u8); src[o] = 0 as u8
  }
  if chk >= 0 { sys_close(chk) }
  // 2nd fallback: nxasm/<name>.nx -- so the TOOLCHAIN itself (assembler/linker) is built
  // through THIS runner's retry guard, never direct 1-shot (2026-06-09 lesson: a direct
  // unguarded nxasm rebuild handed back a nondeterministic miscompile that exited pre-pass0).
  let chk2: i64 = sys_openat_rd(src)
  if chk2 < 0 {
      o = 0
      o = sbr_cat(src, o, "nxasm/" as *u8); o = sbr_cat(src, o, name); o = sbr_cat(src, o, ".nx" as *u8); src[o] = 0 as u8
  }
  if chk2 >= 0 { sys_close(chk2) }
  // 3rd fallback: runtime/wiki/<name>.nx -- the internal wiki engine (nx_wiki_main) and
  // its render organs live here, NOT in runtime/ or _hdl_build/. Mirrors the fallbacks
  // above exactly (reopen src; if still missing, rewrite to the next candidate path).
  // Added 2026-06-15 (a wiki organ otherwise mis-compiled on a bogus nxasm/<name>.nx path
  // and surfaced as a misleading "COMPILE-FAIL (empty .s)").
  let chk3: i64 = sys_openat_rd(src)
  if chk3 < 0 {
      o = 0
      o = sbr_cat(src, o, "runtime/wiki/" as *u8); o = sbr_cat(src, o, name); o = sbr_cat(src, o, ".nx" as *u8); src[o] = 0 as u8
  }
  if chk3 >= 0 { sys_close(chk3) }
  // (The buildroot/ path-prefix fallbacks that briefly lived here were REMOVED: the CWD is anchored
  //  once at the top of main instead, which fixes the source probe, the toolchain, the admission
  //  binary, tree_canon.conf and nx_cc's import resolution together rather than one of the five.)
  // FINAL existence verdict: if NONE of the candidate paths resolved to a real file, fail
  // LOUD with SOURCE-NOT-FOUND rather than running the compiler on a non-existent path
  // (which produces an empty .s and the misleading "COMPILE-FAIL" above). Fail-fast at the
  // boundary (Cardinal 12 + Cardinal 20: a build that can't find its source must say so).
  let chkf: i64 = sys_openat_rd(src)
  if chkf < 0 {
      sbr_puts("[nx_sov_build_run] " as *u8); sbr_puts(name)
      sbr_puts(": SOURCE-NOT-FOUND (probed runtime/_hdl_build/, runtime/, nxasm/, runtime/wiki/ -- relative to CWD, which is anchored to the build tree at startup)\n" as *u8)
      sys_exit(SBR_USAGE); return SBR_USAGE
  }
  sys_close(chkf)
  // BUILD OUTPUT LIVES IN THE REPO, NOT /tmp (operator 2026-07-27). WSL's /tmp is wiped
  // between sessions, which silently deleted built ELFs mid-run and made scripts that
  // referenced them fail in confusing ways (a documented recurring trap). `_build/` is
  // repo-local and durable; mkdir is idempotent (EEXIST is fine, hence the ignored rc).
  sys_mkdir("_build\x00" as *u8, 493)
  // PER-TARGET BUILD LOCK (seq1260, 2026-07-29): two concurrent builds of the SAME target used to
  // interleave on _build/<name>.{s,sov.elf} -- one overwrote the other's artifact MID-SWEEP and a
  // BD control curve read garbage (the /api/build shared-capture class at the local tier). Blocking
  // flock on _build/<name>.lock serializes per target, held through compile->assemble->install and
  // RELEASED before the run phase (a long-running target must never wedge future rebuilds; an
  // already-running process keeps its inode across the atomic rename, so rebuild-under-run is safe).
  // Cross-target builds never contend; process exit releases (crash-safe); the lock file is NEVER
  // unlinked (the documented lock-file law).
  let lockpath: *u8 = sys_mmap(256); o = 0
  o = sbr_cat(lockpath, o, "_build/" as *u8); o = sbr_cat(lockpath, o, name); o = sbr_cat(lockpath, o, ".lock" as *u8); lockpath[o] = 0 as u8
  let lockfd: i64 = sys_openat_wr(lockpath, 0x1a4)
  if lockfd >= 0 { sys_flock(lockfd, SYS_LOCK_EX) }
  let spath: *u8 = sys_mmap(256); o = 0
  o = sbr_cat(spath, o, "_build/" as *u8); o = sbr_cat(spath, o, name); o = sbr_cat(spath, o, ".s" as *u8); spath[o] = 0 as u8
  let elfpath: *u8 = sys_mmap(256); o = 0
  o = sbr_cat(elfpath, o, "_build/" as *u8); o = sbr_cat(elfpath, o, name); o = sbr_cat(elfpath, o, ".sov.elf" as *u8); elfpath[o] = 0 as u8
  // FAIL-LOUD (seq132, 2026-07-19): remove any STALE _build/<name>.sov.elf from a prior build BEFORE
  // compiling, so a failed build can never leave the previous working binary behind to be staged as a
  // false "BUILT" (the masking trap that cost a 3-reship cascade).
  //
  // ROOT FIX seq363 (2026-07-30): this used to TRUNCATE the stale artifact to 0 bytes via O_TRUNC and
  // leave it there. That achieved the anti-staleness goal but replaced one fail-open with a weaker one:
  // after a COMPILE-FAIL a 0-byte file REMAINED on disk, so `does the elf exist?` -- the check every
  // naive caller actually writes -- still answered YES for a build that produced nothing. Measured
  // 2026-07-30: a deliberately-broken target left _build/<t>.sov.elf at 0 bytes, and separately a PIPE
  // swallows this runner's exit code, so neither the artifact nor `$?` was trustworthy.
  //
  // UNLINK instead. The invariant becomes the one callers already assume: THE ARTIFACT EXISTS IF AND
  // ONLY IF THE BUILD SUCCEEDED. Downstream ELF-magic/size guards (nx_hostctl cmd_buildrun, /api/promote,
  // md_tc_elf_size) all still hold -- this makes them belt-and-suspenders rather than load-bearing.
  // Success path is unchanged: the atomic rename below creates the file fresh.
  // MOVED 2026-09-05 (measured on nx_goalmap_gate the day it was built): this unlink used to run HERE, BEFORE
  // build admission, tree-canon admission and the build-cache check -- so an admission REFUSAL (which is not
  // a build failure) destroyed the prior fossil, and every drift and staleness instrument that compares
  // against _build/<t>.sov.elf then measured against an absence (CLAUDE.md 2026-08-28 and 2026-09-04; debt
  // 1787078015 recurrence). The unlink now sits immediately before the compile loop, after every refusal has
  // had its say and only on a cache MISS, so THE ARTIFACT EXISTS IFF THE LAST ATTEMPT THAT REACHED THE
  // COMPILER SUCCEEDED -- the invariant callers already assume, now also true across refusals.
1189
  // SOVEREIGN compiler (self-hosted), NOT nx_cc_known_good (= the C
  // bootstrap, FORBIDDEN on the build path per operator law -- C is
  // for benchmarking only). Fixed 2026-06-09 during C2-deploy.
  let compiler: *u8 = "_offc/nx_cc_sovereign.elf" as *u8
  // the CURRENT (post-cl-shift-fix, 2026-06-09) sovereign assembler. The older _offc/nxasm_x86.elf
  // (2026-05-30) systemically mis-encodes registers->r15 and segfaults even ret-42 -- do NOT use it.
  let asm_tool: *u8 = "_offc/nxasm_x86_main.elf" as *u8
1197
  let envp: *i64 = sys_mmap(8*4) as *i64
  envp[0] = "PATH=/usr/bin:/bin" as *u8 as i64; envp[1] = 0
1200
  let devnull: i64 = sys_openat_wr("/dev/null" as *u8, 0x1a4)   // mute nx_cc's symbol-table dump
1202
  // ---- BUILD ADMISSION (2026-08-01): consult nx_build_admit BEFORE forking the compiler.
  // MEASURED THE NIGHT THIS LANDED: load average 132.58, 334MB available of 36GB, four concurrent
  // compiles -- builds were being OOM-killed mid-flight for every seat sharing this host, and two of
  // mine died that way. nx_build_admit has existed since 2026-07-30 and NOTHING called it: its own
  // header names ma_do_build as the filed rung, and THIS runner -- the path agents actually invoke --
  // was never wired either. A COMPILE IS A HEAVY LAUNCH.
  // Refuse LOUDLY rather than pile on and be killed. That is the memfloor law already on the board:
  // REFUSE, NEVER SILENTLY SHRINK. A build that never starts is recoverable; a wedged host is not.
  //   0 GRANT | 3 DENY-MEM (below the memory floor) | 4 QUEUE (D-state I/O storm, run-queue saturation, or the storm ceiling -- NOT plain 1-minute load: the conf sets max_centiload unreachable)
  //   5 CANNOT-MEASURE (unreadable /proc -> fail-CLOSED by construction, never wave through)
  // FAIL-OPEN ON ABSENCE ONLY: a missing admitter makes execve return 127 and we proceed, so a tree
  // without it still builds -- but any verdict it DOES return is obeyed. Absence is not permission.
  let sbr_admit: *u8 = "_build/nx_build_admit.sov.elf" as *u8
  // THRESHOLDS ARE EXPLICIT, AND ONLY THE CAUSAL ONE IS ARMED (2026-08-01).
  // MEMORY FLOOR 512MB IS ARMED: it is the DIRECTLY MEASURED cause -- builds were OOM-killed
  // tonight at 334MB available, which is below this floor, so this check would have refused
  // exactly the builds that died instead of letting them pile on and be killed.
  // LOAD CEILING IS DELIBERATELY DISABLED (1000000 centiload = load 10000, unreachable) because
  // it is UNCALIBRATED for this host: the admitter default is 400 (load 4.00) while this Synology
  // IDLES at 17.62/24.80/36.19 and only wedged at 132.58. Arming it at the default would refuse
  // every build for every seat -- including this runner own rebuild, a self-bricking guard.
  // Picking a number that merely produces the outcome I want would be FITTING, NOT MODELLING.
  // TO ARM IT: sample /proc/loadavg over a representative window, set the ceiling above the normal
  // distribution and below the wedge point, and record the measurement that justifies the number.
  let sbr_aargv: *i64 = sys_mmap(8*6) as *i64
  sbr_aargv[0] = sbr_admit as i64
  sbr_aargv[1] = "check" as *u8 as i64
  // NO THRESHOLDS PASSED (2026-08-18). The comment that stood here said "if this number ever moves,
  // move BOTH" -- the very sentence that proves two copies were one too many (and mgmt's max was
  // 100000 while this one was 1000000: they had already drifted). nx_build_admit now reads THE ONE
  // envelope from knowledge/build_admit.conf (../knowledge/ from this buildroot-anchored CWD) and
  // prints envelope_src=conf; every caller that passes nothing gets the same bar as /api/build.
  sbr_aargv[2] = 0
  var sbr_arc: i64 = sbr_run(sbr_admit, sbr_aargv, envp, 0 - 1, 0 - 1, deadline_ms)
  // DURABLE FALLBACK (2026-09-03). The admitter above is the _build FOSSIL, and A REFUSED BUILD DELETES
  // THAT FOSSIL -- so one refusal silently DISARMS THIS GUARD for the next build, precisely when the box
  // is busiest and the guard matters most. MEASURED THIS DAY, on a genuinely storming host:
  //   BUILD ADMISSION DID NOT RUN (rc=127 ...). PROCEEDING UNGUARDED
  // solely because an earlier refusal had eaten the artifact. The fail-open-on-absence rule documented
  // above is deliberate and STAYS -- a tree that has never built the admitter must still bootstrap.
  // But ABSENCE-BY-DELETION IS NOT ABSENCE-BY-BOOTSTRAP, and the PROMOTED binary is the durable copy that
  // survives a refusal. CWD is buildroot, so the serving root is one level up.
  // STRICTLY ADDITIVE BY CONSTRUCTION: it runs only when the first attempt found NOTHING to run, so it can
  // only ever ADD a guard where there was none. A present fossil behaves exactly as before, and a tree
  // missing both copies now refuses before compilation.
  let sbr_rc_notfound: i64 = 127
  if sbr_arc == sbr_rc_notfound {
      let sbr_admit2: *u8 = "../nx_build_admit.elf" as *u8
      sbr_aargv[0] = sbr_admit2 as i64
      sbr_arc = sbr_run(sbr_admit2, sbr_aargv, envp, 0 - 1, 0 - 1, deadline_ms)
      if sbr_arc != sbr_rc_notfound {
          sbr_puts("[nx_sov_build_run] admission fossil absent (a refused build deletes it); GUARDED by the PROMOTED ../nx_build_admit.elf instead.\n" as *u8)
      }
  }
  // EXIT IS SBR_ADMIT_REFUSED(6) FOR ALL THREE DENIALS (restored in the 2026-08-03 fork merge --
  // the NAS branch had regressed to returning the admitter's raw 3/4/5, which COLLIDE with
  // COMPILE_FAIL(3)/ASM_FAIL(4): a wait-and-retry signal decoding as a broken build). The REASON
  // stays in the message; the code says only "admission refused, not a build failure".
  if sbr_arc == 3 {
      sbr_puts("[nx_sov_build_run] REFUSED-BUILD-ADMIT rc=3 DENY-MEM -- available memory is BELOW THE FLOOR. Compiling now risks wedging the HOST, not just this build. Wait for headroom and retry.\n" as *u8)
      sys_exit(SBR_ADMIT_REFUSED); return SBR_ADMIT_REFUSED
  }
  if sbr_arc == 4 {
      sbr_puts("[nx_sov_build_run] REFUSED-BUILD-ADMIT rc=4 QUEUE -- the BUILD-ADMIT report ABOVE names which conjunct fired (D-state I/O storm, run-queue saturation, or the storm ceiling). THIS RUNNER DELIBERATELY DOES NOT RESTATE THE CAUSE: a hand-copied paraphrase of another organ's verdict drifts from it silently and sends every reader at the wrong cause -- and this line used to name the 1-minute load ceiling, which the shared conf sets UNREACHABLE, so it named the one conjunct that CANNOT fire. Nothing is queued by THIS runner: re-issue once the box clears (admission re-measures per call); pace re-issues, never spin.\n" as *u8)
      sys_exit(SBR_ADMIT_REFUSED); return SBR_ADMIT_REFUSED
  }
  if sbr_arc == 5 {
      sbr_puts("[nx_sov_build_run] REFUSED-BUILD-ADMIT rc=5 CANNOT-MEASURE -- /proc unreadable, so admission FAILS CLOSED by construction. A guard that cannot measure must refuse, never wave through.\n" as *u8)
      sys_exit(SBR_ADMIT_REFUSED); return SBR_ADMIT_REFUSED
  }
  if bci_resource_allowed(sbr_arc) != 1 {
      sbr_puts("[nx_sov_build_run] REFUSED-BUILD-ADMIT detector_rc=" as *u8); sbr_putn(sbr_arc)
      sbr_puts(" -- no explicit GRANT. Restore the admitter or resolve its failure; bootstrap must provision admission before compiling. No compiler launched.\n" as *u8)
      sys_exit(SBR_ADMIT_REFUSED); return SBR_ADMIT_REFUSED
  }
1278
  // ---- TREE-CANON ADMISSION (2026-08-03, debt 1785622769): a build must never compile a copy
  // that diverges from canon. ../knowledge/tree_canon.conf (cwd is buildroot; the conf lives at
  // the nishihost root) lists tree-root-relative paths that MUST be byte-identical across every
  // tree that can build them. Row grammar: '#' comment, blank ignored, '!path' = FREEZE EVERY
  // BUILD while divergent (shared infrastructure -- a fork there miscompiles everything
  // downstream), 'path' = refuse only the build OF THAT FILE (a lane's own divergence must not
  // block unrelated targets). The other tree's sizes come from the last pushed authoring
  // manifest (../knowledge/status/treecanon_laptop.mf, produced by nx_treediff on that tree).
  // SIZE IS A SCREEN, NOT PROOF OF IDENTITY (nx_treediff's own declared bound) -- equal-size
  // rewrites pass here; nx_treecanon_gate stays the tree-level instrument.
  // ⚠the manifest is AS FRESH AS ITS LAST PUSH: a stale one can false-pass a scoped row. The
  // authoring loop owns pushing it after edits; this check is the floor, not the ceiling.
  // Admission requires a valid nonempty rulebook and SHA256 manifest. Bootstrap provisions these
  // inputs before using the runner. A size screen remains diagnostic history, not content proof.
  let cn_conf_l: *i64 = sys_mmap(16) as *i64
  let cn_conf: *u8 = sys_read_file("../knowledge/tree_canon.conf" as *u8, cn_conf_l)
  let cn_mf_l: *i64 = sys_mmap(16) as *i64
  let cn_mf: *u8 = sys_read_file("../knowledge/status/treecanon_laptop.mf" as *u8, cn_mf_l)
  // The DIGEST manifest (nx_treehash on the authoring tree). When present it WINS: it decides
  // identity by content, which is the only thing a size screen cannot do.
  let cn_hmf_l: *i64 = sys_mmap(16) as *i64
  let cn_hmf: *u8 = sys_read_file("../knowledge/status/treecanon_laptop_hash.mf" as *u8, cn_hmf_l)
  let cn_rules: i64 = bci_conf_rows(cn_conf, cn_conf_l[0], SBR_CANON_PATH_BYTES - SBR_RUNTIME_PREFIX_BYTES - 1)
  if cn_rules <= 0 {
      sbr_puts("[nx_sov_build_run] REFUSED-TREE-CANON INPUT: rulebook missing, empty, malformed or path out of bounds. Provision ../knowledge/tree_canon.conf; no compiler launched.\n" as *u8)
      sys_exit(SBR_CANON_REFUSED); return SBR_CANON_REFUSED
  }
  if (cn_hmf as i64) == 0 {
      sbr_puts("[nx_sov_build_run] REFUSED-TREE-CANON INPUT: SHA256 manifest missing. Size-only evidence cannot admit a build; provision ../knowledge/status/treecanon_laptop_hash.mf.\n" as *u8)
      sys_exit(SBR_CANON_REFUSED); return SBR_CANON_REFUSED
  }
  if cn_hmf_l[0] <= 0 {
      sbr_puts("[nx_sov_build_run] REFUSED-TREE-CANON INPUT: SHA256 manifest empty; no compiler launched.\n" as *u8)
      sys_exit(SBR_CANON_REFUSED); return SBR_CANON_REFUSED
  }
  sbr_puts("[nx_sov_build_run] TREE-CANON RULEBOOK VALID rules=" as *u8); sbr_putn(cn_rules); sbr_puts(" SHA256-evidence=loaded; relevant rows checked below\n" as *u8)
  var cn_have: i64 = 0
  if (cn_mf as i64) != 0 { cn_have = 1 }
  if (cn_hmf as i64) != 0 { cn_have = 1 }
  if (cn_conf as i64) != 0 { if cn_have == 1 {
      // the canon rows are relative to the runtime root; src is "runtime/<rel>" for every probe
      // path except the nxasm/ fallback (toolchain sources are not canon-governed rows today)
      var cn_isrt: i64 = 1
      let cn_rt: *u8 = "runtime/" as *u8
      var cn_i: i64 = 0
      while cn_i < 8 { if src[cn_i] != cn_rt[cn_i] { cn_isrt = 0 } cn_i = cn_i + 1 }
      var cn_srclen: i64 = 0
      while src[cn_srclen] != (0 as u8) { cn_srclen = cn_srclen + 1 }
      let cn_path: *u8 = sys_mmap(SBR_CANON_PATH_BYTES)
      let cn_cl: i64 = cn_conf_l[0]
      let cn_ml: i64 = cn_mf_l[0]
      var cn_p: i64 = 0
      while cn_p < cn_cl {
          var cn_e: i64 = cn_p
          var cn_go: i64 = 1
          while cn_go == 1 {
              if cn_e >= cn_cl { cn_go = 0 }
              if cn_go == 1 { if cn_conf[cn_e] == (10 as u8) { cn_go = 0 } }
              if cn_go == 1 { cn_e = cn_e + 1 }
          }
          var cn_len: i64 = cn_e - cn_p
          if cn_len > 0 { if cn_conf[cn_p + cn_len - 1] == (13 as u8) { cn_len = cn_len - 1 } }   // CRLF-tolerant
          var cn_frozen: i64 = 0
          var cn_ps: i64 = cn_p
          if cn_len > 0 { if cn_conf[cn_ps] == (33 as u8) { cn_frozen = 1; cn_ps = cn_ps + 1; cn_len = cn_len - 1 } }
          var cn_live: i64 = 0
          if cn_len > 0 { if cn_conf[cn_ps] != (35 as u8) { cn_live = 1 } }
          if cn_live == 1 {
              // relevant = frozen row, OR the row IS the file this build compiles
              var cn_rel: i64 = cn_frozen
              if cn_isrt == 1 { if sbr_ceq_at(src, 8, cn_srclen - 8, cn_conf, cn_ps, cn_len) == 1 { cn_rel = 1 } }
              if cn_rel == 1 {
                  var cq: i64 = 0
                  cq = sbr_cat(cn_path, cq, "runtime/" as *u8)
                  var ck: i64 = 0
                  while ck < cn_len { cn_path[cq] = cn_conf[cn_ps + ck]; cq = cq + 1; ck = ck + 1 }
                  cn_path[cq] = 0 as u8
                  let cn_nas: i64 = sbr_filesize(cn_path)
                  var cn_found: i64 = 0
                  var cn_lap: i64 = 0 - 1
                  var cn_div: i64 = 0
                  var cn_hmode: i64 = 0
                  var cn_hash_ok: i64 = 0
                  var cn_matches: i64 = 0
                  if (cn_hmf as i64) != 0 { cn_hmode = 1 }
                  let cn_lhex: *u8 = sys_mmap(128)
                  let cn_mhex: *u8 = sys_mmap(128)
                  // ---- CONTENT MODE: digest rows are "<64hex> <bytes> <relpath>" ----
                  if cn_hmode == 1 {
                      var hq: i64 = 0
                      while hq < SBR_SHA_HEX { cn_mhex[hq] = SBR_QMARK as u8; hq = hq + 1 }
                      cn_mhex[SBR_SHA_HEX] = 0 as u8
                      let cn_hash_rc: i64 = sbr_sha_hex(cn_path, cn_lhex)
                      if cn_hash_rc == 0 { cn_hash_ok = 1 }
                      if cn_hash_rc != 0 {
                          var hz: i64 = 0
                          while hz < SBR_SHA_HEX { cn_lhex[hz] = SBR_QMARK as u8; hz = hz + 1 }
                          cn_lhex[SBR_SHA_HEX] = 0 as u8
                      }
                      var hp: i64 = 0
                      let cn_hl: i64 = cn_hmf_l[0]
                      while hp < cn_hl {
                          var he: i64 = hp
                          var hg: i64 = 1
                          while hg == 1 {
                              if he >= cn_hl { hg = 0 }
                              if hg == 1 { if cn_hmf[he] == (10 as u8) { hg = 0 } }
                              if hg == 1 { he = he + 1 }
                          }
                          var hl2: i64 = he - hp
                          if hl2 > 0 { if cn_hmf[hp + hl2 - 1] == (13 as u8) { hl2 = hl2 - 1 } }
                          if hl2 > SBR_SHA_HEX + 2 {
                              // the SECOND space ends the size field; the relpath follows it
                              var s2: i64 = 0 - 1
                              var hi2: i64 = SBR_SHA_HEX + 1
                              while hi2 < hl2 { if s2 < 0 { if cn_hmf[hp + hi2] == (32 as u8) { s2 = hi2 } } hi2 = hi2 + 1 }
                              if s2 > 0 {
                                  if sbr_ceq_at(cn_hmf, hp + s2 + 1, hl2 - s2 - 1, cn_conf, cn_ps, cn_len) == 1 {
                                      if bci_hash_row(cn_hmf, hp, hl2) != 1 {
                                          sbr_puts("[nx_sov_build_run] REFUSED-TREE-CANON EVIDENCE: malformed SHA256 row for " as *u8); sbr_puts(cn_path); sbr_puts("\n" as *u8)
                                          sys_exit(SBR_CANON_REFUSED); return SBR_CANON_REFUSED
                                      }
                                      cn_found = 1
                                      cn_matches = cn_matches + 1
                                      var hk: i64 = 0
                                      while hk < SBR_SHA_HEX { cn_mhex[hk] = cn_hmf[hp + hk]; hk = hk + 1 }
                                  }
                              }
                          }
                          hp = he + 1
                      }
                      if cn_found == 1 {
                          var hd: i64 = 0
                          while hd < SBR_SHA_HEX { if cn_lhex[hd] != cn_mhex[hd] { cn_div = 1 } hd = hd + 1 }
                      }
                  }
                  // ---- SIZE MODE (unchanged): only when no digest manifest was published ----
                  if cn_hmode == 0 {
                  var mp: i64 = 0
                  while mp < cn_ml {
                      var me: i64 = mp
                      var mg: i64 = 1
                      while mg == 1 {
                          if me >= cn_ml { mg = 0 }
                          if mg == 1 { if cn_mf[me] == (10 as u8) { mg = 0 } }
                          if mg == 1 { me = me + 1 }
                      }
                      var ml2: i64 = me - mp
                      if ml2 > 0 { if cn_mf[mp + ml2 - 1] == (13 as u8) { ml2 = ml2 - 1 } }
                      // split at the first space
                      var ms: i64 = 0 - 1
                      var mi: i64 = 0
                      while mi < ml2 { if ms < 0 { if cn_mf[mp + mi] == (32 as u8) { ms = mi } } mi = mi + 1 }
                      if ms > 0 {
                          if sbr_ceq_at(cn_mf, mp + ms + 1, ml2 - ms - 1, cn_conf, cn_ps, cn_len) == 1 {
                              cn_found = 1
                              var mv: i64 = 0
                              var md: i64 = 0
                              while md < ms { mv = mv * 10 + ((cn_mf[mp + md] as i64) - 48); md = md + 1 }
                              cn_lap = mv
                          }
                      }
                      mp = me + 1
                  }
                  if cn_found == 1 { if cn_lap != cn_nas { cn_div = 1 } }
                  }
                  // Timestamps cannot repair missing, duplicate or unreadable evidence.
                  if cn_matches != 1 {
                      sbr_puts("[nx_sov_build_run] REFUSED-TREE-CANON EVIDENCE: expected one SHA256 row for " as *u8); sbr_puts(cn_path)
                      sbr_puts(" matches=" as *u8); sbr_putn(cn_matches); sbr_puts("\n" as *u8)
                      sys_exit(SBR_CANON_REFUSED); return SBR_CANON_REFUSED
                  }
                  if cn_nas <= 0 {
                      sbr_puts("[nx_sov_build_run] REFUSED-TREE-CANON EVIDENCE: source absent or empty: " as *u8); sbr_puts(cn_path); sbr_puts("\n" as *u8)
                      sys_exit(SBR_CANON_REFUSED); return SBR_CANON_REFUSED
                  }
                  if cn_hash_ok != 1 {
                      sbr_puts("[nx_sov_build_run] REFUSED-TREE-CANON EVIDENCE: source digest unreadable: " as *u8); sbr_puts(cn_path); sbr_puts("\n" as *u8)
                      sys_exit(SBR_CANON_REFUSED); return SBR_CANON_REFUSED
                  }
                  // a canon row ABSENT from the authoring manifest is divergent in EITHER mode
                  if cn_found == 0 { cn_div = 1 }
                  if cn_nas == 0 { cn_div = 1 }
                  // ---- STALENESS IS NOT A FORK (2026-08-07) ------------------------------------------
                  // This guard REFUSED on any content difference whatever, and the manifest it compares
                  // against is a snapshot of ONE laptop refreshed by a SessionStart hook. So one seat
                  // saving a widely-imported file made EVERY build of EVERY dependent target fail for
                  // EVERY seat until somebody re-ran the manifest push. Measured live: another seat was
                  // editing runtime/nx_syscalls.nx -- which essentially every organ imports -- and it
                  // changed three times in ~20 minutes; each time converge+push+build succeeded
                  // IMMEDIATELY, proving the refusal was staleness and not a defect in the code.
                  // ★A GUARD THAT IS RIGHT ABOUT CONTENT IDENTITY CAN STILL BE WRONG ABOUT AVAILABILITY:
                  // IT TURNED ONE SEAT'S SAVE INTO AN ESTATE-WIDE BUILD OUTAGE.
                  //
                  // THE HARM IT ACTUALLY EXISTS TO PREVENT is compiling a copy that is BEHIND the
                  // authoring tree -- that is how the unfreed-mmap fix got applied twice. Being AHEAD is
                  // not that harm: it is just the newest work, and building does not write source.
                  // The NAS cannot do symbol containment here (the manifest carries only sha+bytes+path,
                  // never the laptop's content), but it CAN answer the question that decides the case:
                  // was this file modified AFTER the snapshot was taken?
                  //   nas mtime  >  manifest mtime  -> the snapshot is simply STALE about this file,
                  //                                    this tree holds the newer bytes -> PROCEED, LOUDLY.
                  //   nas mtime  <= manifest mtime  -> the snapshot SAW this content and still disagrees
                  //                                    -> a real fork, the laptop is ahead -> REFUSE.
                  // No new constant, no new data, and it fails CLOSED whenever either stat is unreadable.
                  if cn_div == 1 {
                      // ⚠cn_conf is the CONF FILE'S CONTENT BUFFER, not a path -- the row is a
                      // (buffer, offset, length) triple. Passing it to a stat() stats garbage, which
                      // returns -1 and silently skipped this whole check: the first version of this
                      // fix REFUSED exactly as before and looked like the branch was simply wrong.
                      // cn_path is the resolved tree-relative path the refusal message already prints.
                      // ⚠And the manifest is ../knowledge/... because main() anchors CWD to buildroot.
                      // A PATH THAT IS RIGHT FOR THE MESSAGE IS NOT AUTOMATICALLY RIGHT FOR A SYSCALL.
                      let cn_fmt: i64 = sbr_mtime(cn_path)
                      let cn_mmt: i64 = sbr_mtime("../knowledge/status/treecanon_laptop_hash.mf" as *u8)
                      if cn_fmt > 0 {
                          if cn_mmt > 0 {
                              if cn_fmt > cn_mmt {
                                  sbr_puts("[nx_sov_build_run] TREE-CANON STALE-NOT-FORKED: canon path " as *u8)
                                  sbr_puts(cn_path)
                                  sbr_puts(" differs from the authoring manifest, but THIS TREE'S COPY IS NEWER THAN THE SNAPSHOT (file mtime " as *u8)
                                  sbr_putn(cn_fmt)
                                  sbr_puts(" > manifest mtime " as *u8)
                                  sbr_putn(cn_mmt)
                                  sbr_puts("), so the manifest is behind, not the tree. PROCEEDING on the newer bytes -- re-run the treecanon push to re-sync the authoring tree.\
1504" as *u8)
                                  cn_div = 0
                              }
                          }
                      }
                  }
                  if cn_div == 1 {
                      sbr_puts("[nx_sov_build_run] REFUSED-TREE-CANON rc=7: canon path " as *u8)
                      sbr_puts(cn_path)
                      if cn_hmode == 1 {
                          sbr_puts(" DIVERGES across trees by CONTENT (sha256) -- this tree=" as *u8)
                          sbr_puts(cn_lhex)
                          sbr_puts(" authoring manifest=" as *u8)
                          sbr_puts(cn_mhex)
                          sbr_puts(" ('?' repeated = file unreadable, or the row is absent from the manifest). " as *u8)
                      }
                      if cn_hmode == 0 {
                          sbr_puts(" DIVERGES across trees by SIZE (this tree=" as *u8); sbr_putn(cn_nas)
                          sbr_puts("B, authoring manifest=" as *u8); sbr_putn(cn_lap)
                          sbr_puts("B; -1 = absent). NOTE: this is the SIZE SCREEN, so equal-size rewrites would have PASSED -- push a nx_treehash digest manifest to close that class. " as *u8)
                      }
                      sbr_puts("Building now would compile a FORKED copy -- the exact class that applied the unfreed-mmap fix twice. Remedy: body-diff and converge the file in BOTH trees (merge per file, never wholesale), regenerate + push knowledge/status/treecanon_laptop_hash.mf (and treecanon_laptop.mf), then rebuild.\n" as *u8)
                      sys_exit(SBR_CANON_REFUSED); return SBR_CANON_REFUSED
                  }
              }
          }
          cn_p = cn_e + 1
      }
  } }
1533
  // ---- compile+ASSEMBLE with recompile-retry until the .s ASSEMBLES CLEANLY (compiler nondeterminism guard).
  // ROOT FIX 2026-06-25: the old guard stopped at the first NON-EMPTY .s -- but nx_cc's nondeterminism also
  // TRUNCATES (a non-empty .s missing the trailing `main` -> nxasm rc=102 "UNDEFINED label: main", caught x3
  // assembling nx_raci_sov / nx_pattern_library). So success now REQUIRES rc_a==0 from nxasm, not merely
  // non-empty bytes -> truncation-nondeterminism becomes reliability. The assemble lands in tmpelf (atomic
  // rename after the loop). If a real DETERMINISTIC miscompile, the retries exhaust + we LOUD-fail saying so. ----
  // ---- CONTENT-ADDRESSED BUILD CACHE: try a hit BEFORE compiling (B2, 2026-08-17). FAIL-OPEN: any
  //      problem here leaves cache_hit=0 and the build proceeds EXACTLY as before this block existed. ----
  var cache_hit: i64 = 0
  var cache_have_key: i64 = 0
  let cachekey: *u8 = sys_mmap(SBR_SHA_HEX + 2)
  let cachepath: *u8 = sys_mmap(SBR_CACHE_TMPW)
  // EVERY path prints one BUILD-CACHE line (HIT | MISS reason=...), so a silent build can never be
  // mistaken for a cached one, and a gate can assert on the reason rather than on the absence of a word.
  var cache_route: i64 = 0     // 0 = consult the store | 1 = toolchain target | 2 = --no-cache | 3 = conf disabled
  if sbr_is_toolchain(name) == 1 { cache_route = 1 }
  if cache_route == 0 { if no_cache == 1 { cache_route = 2 } }
  if cache_route == 0 { if sbr_cache_enabled() == 0 { cache_route = 3 } }
  if cache_route == 1 { bld_cache_cas_say(name, "MISS reason=toolchain-target (a toolchain binary is in every key; it is never cached)" as *u8, 0 as *u8); bld_cache_cas_nl() }
  if cache_route == 2 { bld_cache_cas_say(name, "MISS reason=disabled-by-flag (--no-cache)" as *u8, 0 as *u8); bld_cache_cas_nl() }
  if cache_route == 3 { bld_cache_cas_say(name, "MISS reason=disabled-by-conf (../knowledge/buildcache.conf cache_enabled=0)" as *u8, 0 as *u8); bld_cache_cas_nl() }
  if cache_route == 0 {
      if sbr_cache_key(src, compiler, asm_tool, want_debug, cachekey) != 0 {
          bld_cache_cas_say(name, "MISS reason=key-unavailable (closure could not be expanded for hashing; building normally)" as *u8, 0 as *u8); bld_cache_cas_nl()
      }
      if sbr_cache_key(src, compiler, asm_tool, want_debug, cachekey) == 0 {
          cache_have_key = 1
          sys_mkdir("_build/cache" as *u8, 0x1ed)   // 0755; idempotent; already-exists is fine
          var cq: i64 = 0
          cq = sbr_cat(cachepath, cq, "_build/cache/" as *u8)
          cq = sbr_cat(cachepath, cq, cachekey)
          cq = sbr_cat(cachepath, cq, ".sov.elf" as *u8); cachepath[cq] = 0 as u8
          cache_hit = bld_cache_cas(cachekey, cachepath, elfpath, name)
      }
  }
  // FAIL-LOUD unlink of the stale fossil (seq132 / seq363), MOVED HERE 2026-09-05: every refusal above has
  // already exited and a cache HIT has just materialised the artifact, so only a MISS that is about to
  // compile may remove the prior binary. A refused build now leaves the last good fossil in place.
  if cache_hit == 0 { sys_unlinkat(elfpath) }
  let tmpelf: *u8 = sys_mmap(256); o = 0
  o = sbr_cat(tmpelf, o, "_build/_sbr_asm_out." as *u8); o = sbr_cat(tmpelf, o, name); tmpelf[o] = 0 as u8
  var asmbytes: i64 = 0
  var rc_a: i64 = 0 - 1
  var built: i64 = 0
  var tries: i64 = 0
  if cache_hit == 1 { built = 1; tries = SBR_MAX_RETRIES }   // BUILD-CACHE HIT: artifact already in elfpath, skip compile+assemble
  while tries < SBR_MAX_RETRIES {
      let sfd: i64 = sys_openat_wr(spath, 0x1a4)
      // FLAG POSITION IS LOAD-BEARING, NOT STYLISTIC. nx_cc's argv walk EXITS at the first non-flag
      // argument (nx_compile_x86.nx: `path_addr = arg as i64; i = argc`), so ANY flag placed AFTER the
      // source path is never seen. -g therefore goes BEFORE src. Had it gone after, the build would
      // have succeeded, printed the DEBUG BUILD banner, and produced a binary with no .debug_line --
      // i.e. nx_addr2line would still say "built without -g" and the flag would read as broken rather
      // than misplaced. Widened to 6 slots so a future third flag cannot silently overrun the 4 this
      // needs (compiler, -g, src, NULL); mmap rounds to a page either way, so the cost is zero and the
      // declared size states the intent.
      let cc: *i64 = sys_mmap(8*6) as *i64
      var ci: i64 = 0
      cc[ci] = compiler as i64; ci = ci + 1
      if want_debug == 1 { cc[ci] = "-g" as *u8 as i64; ci = ci + 1 }
      cc[ci] = src as i64; ci = ci + 1
      cc[ci] = 0
      let rc_c: i64 = sbr_run(compiler, cc, envp, sfd, devnull, deadline_ms)
      sys_close(sfd)
      // A HANG IS NOT RETRIED. The retry loop above exists for nx_cc's nondeterministic .s
      // truncation -- a real, transient class. A timeout is the opposite: deterministic, and each
      // retry would burn another full deadline before failing the same way.
      if rc_c == SBR_TIMEOUT_RC {
          sbr_puts("[nx_sov_build_run] " as *u8); sbr_puts(name)
          sbr_puts(": COMPILE-TIMEOUT -- NOT retried, and NOT a compile failure. nx_cc never answered, so\n" as *u8)
          sbr_puts("  nothing was judged about this source. Do not hunt a syntax error: minimise the input that\n" as *u8)
          sbr_puts("  hangs the compiler and file it against the compiler lane.\n" as *u8)
          sys_exit(SBR_BUILD_TIMEOUT); return SBR_BUILD_TIMEOUT
      }
      asmbytes = sbr_filesize(spath)
      if rc_c == 0 { if asmbytes > SBR_MIN_ASM_BYTES {
          let aa2: *i64 = sys_mmap(8*4) as *i64
          aa2[0] = asm_tool as i64; aa2[1] = spath as i64; aa2[2] = tmpelf as i64; aa2[3] = 0
          rc_a = sbr_run(asm_tool, aa2, envp, 0 - 1, 0 - 1, deadline_ms)
          if rc_a == SBR_TIMEOUT_RC {
              sbr_puts("[nx_sov_build_run] " as *u8); sbr_puts(name)
              sbr_puts(": ASSEMBLE-TIMEOUT -- NOT retried. nxasm never answered on this .s.\n" as *u8)
              sys_exit(SBR_BUILD_TIMEOUT); return SBR_BUILD_TIMEOUT
          }
          if rc_a == 0 { built = 1; tries = SBR_MAX_RETRIES }
      } }
      if tries != SBR_MAX_RETRIES { tries = tries + 1 }
  }
  if built == 0 {
      if asmbytes <= SBR_MIN_ASM_BYTES {
          // ROOT-CAUSE SURFACE (2026-07-06): the retry loop mutes nx_cc's stderr, so a plain source error
          // (undefined function / parse / arg-count) hid behind this opaque "empty .s" (cost a ~15-build blind
          // hunt). Re-run the compiler ONCE with stderr VISIBLE so the REAL diagnostic always prints. Same
          // one-look answer as _offc/nx_ccdiag.elf, now automatic on every failure.
          sbr_puts("[nx_sov_build_run] " as *u8); sbr_puts(name); sbr_puts(": COMPILE-FAIL (empty .s) -- nx_cc says:\n---- nx_cc stderr ----\n" as *u8)
          let dcc: *i64 = sys_mmap(8*4) as *i64
          dcc[0] = compiler as i64; dcc[1] = src as i64; dcc[2] = 0
          sbr_run(compiler, dcc, envp, devnull, 0 - 1, deadline_ms)     // stdout->devnull, stderr VISIBLE = the real cause
          sbr_puts("----------------------\n(usually an undefined fn / missing import / parse error -- NOT a codegen crash; fix the source above)\n" as *u8)
          sys_exit(SBR_COMPILE_FAIL); return SBR_COMPILE_FAIL
      }
      if rc_a > 128 {
          sbr_puts("[nx_sov_build_run] " as *u8); sbr_puts(name); sbr_puts(": NXASM-CRASHED sig=" as *u8); sbr_putn(rc_a - 128); sbr_puts(" (assembler died on this .s -> capacity/robustness bug)\n" as *u8)
          sys_exit(SBR_ASM_FAIL); return SBR_ASM_FAIL
      }
      sbr_puts("[nx_sov_build_run] " as *u8); sbr_puts(name); sbr_puts(": NXASM-FAIL rc=" as *u8); sbr_putn(rc_a)
      sbr_puts(" after recompile-retries -- DETERMINISTIC (not the nondeterministic-truncation class). rc=102 = nxasm 'UNDEFINED label: main' = USUALLY a no-main LIBRARY built standalone -> run its _gate/importer (the one with main), NOT the lib. Else a real deterministic compiler/source miscompile.\n" as *u8)
      sys_exit(SBR_ASM_FAIL); return SBR_ASM_FAIL
  }
1643
  // CORRECTED 2026-06-25: the old comment here claimed the rc=6/102 "ctx-x-output-path" class was
  // "non-reproducible / nxasm outpath codegen CLEAN". That was WRONG -- the real rc=102 is nxasm's pass-2
  // "UNDEFINED label: main" (axc_label_resolve), i.e. nx_cc emitted a TRUNCATED .s missing `main`. It is the
  // COMPILER truncation-nondeterminism, not the output path. The retry loop above now requires a clean assemble,
  // so a truncated .s no longer escapes. tmpelf holds the good ELF -> atomic rename install (temp+rename kept
  // for atomicity = never overwrite a running binary mid-write).
  // On a BUILD-CACHE HIT elfpath already holds the byte-identical artifact, so skip the rename and the
  // store; on a MISS, install the fresh ELF and populate the content-addressed cache (fail-open).
  if cache_hit == 0 {
      sys_renameat(tmpelf, elfpath)
      if cache_have_key == 1 { bld_cache_cas_store(elfpath, cachepath, name); sbr_cache_prune() }
  }
1656
  // ---- LM-026 ROOT FIX: refresh the INSTALLED artifact if one exists -----------------------------
  // Historical trap (cost a full session on the MMU rung): this runner builds to /tmp/<name>.sov.elf,
  // but gates/organs fork _offc/<name>.elf -- so a rebuild left _offc STALE and source edits silently
  // never took effect. Now, on a SUCCESSFUL build, if _offc/<name>.elf ALREADY EXISTS (i.e. <name> is
  // an installed artifact that something forks), atomically refresh it from the fresh build. This is
  // refresh-IF-PRESENT only: throwaway gate/probe builds (run straight from /tmp, no _offc twin) never
  // get a spurious _offc entry. Atomic (write .sbrtmp + renameat) = no torn binary, retires LM-026 at
  // the source. The reactive nx_offc_install guardrail stays as the belt-and-suspenders detector.
  let offcpath: *u8 = sys_mmap(256); o = 0
  o = sbr_cat(offcpath, o, offc_pfx); o = sbr_cat(offcpath, o, name); o = sbr_cat(offcpath, o, ".elf" as *u8); offcpath[o] = 0 as u8
  // The SECOND consumer location: <serving-root>/<name>.elf.  Probed independently of _offc,
  // because most organs have exactly one of the two and the old code only ever looked at _offc.
  let rootpath: *u8 = sys_mmap(256); var ro: i64 = 0
  ro = sbr_cat(rootpath, ro, root_pfx); ro = sbr_cat(rootpath, ro, name); ro = sbr_cat(rootpath, ro, ".elf" as *u8); rootpath[ro] = 0 as u8
  let oex: i64 = sys_openat_rd(offcpath)
  let rex: i64 = sys_openat_rd(rootpath)
  var has_offc: i64 = 0
  var has_root: i64 = 0
  if oex >= 0 { sys_close(oex); has_offc = 1 }
  if rex >= 0 { sys_close(rex); has_root = 1 }
  // ---- THE DECISION IS DELEGATED, NOT MADE HERE (2026-08-26) ----
  // nx_builddeploy_lib owns "may this build write a consumer-visible binary?", so the QUEUED lane and
  // the SEAT lane cannot disagree, and a fixture can hold every combination of its inputs. The probes
  // stay here (does a twin exist, is this a toolchain, is this a declared daemon); the JUDGEMENT moved.
  //
  // WHAT CHANGED: --build-only now installs NOTHING. WHY, measured 2026-08-26 from the queue's OWN
  // artifact knowledge/store/planrun-build-nx_gate_roster_run-:
  //   [nx_sov_build_run] nx_gate_roster_run: DEPLOYED to serving root (twin refresh, live for the
  //   next fork) -> ../nx_gate_roster_run.elf
  // /api/build's load-refusal path forks nx_job_run nx_buildq add; nx_buildq seeds the plan step
  // "nx_sov_build_run <target> --build-only"; nx_orchestrate fires it from the SERVING ROOT -- where
  // this runner's CWD anchor DOES fire, so root_pfx becomes "../" and the twin refresh lands on the
  // LIVE binary. The caller had been told only that its build was deferred and to promote deliberately
  // afterwards. Every promote-lane guard -- nx_contentdiff, nx_behaveprobe, the capability-loss check,
  // the .prev bank -- was bypassed by construction, with no seat anywhere in the loop.
  // A FLAG WHOSE MEANING DEPENDS ON THE CALLER'S CWD CANNOT BE REASONED ABOUT FROM ITS NAME.
  let bd_tc: i64 = sbr_is_toolchain(name)
  let bd_dk: i64 = sbr_is_daemon(name)
  // What the twin probes ALONE would have wanted, kept only so the refusals below can say "there was
  // something here and I declined to write it" instead of going silent.
  var bd_would: i64 = 0
  if has_offc == 1 { bd_would = 1 }
  if has_root == 1 { bd_would = 1 }
  if force_install == 1 { bd_would = 1 }
  let bd_loc: i64 = bd_locations(has_offc, has_root, force_install, build_only, bd_tc, bd_dk)
  let bd_reason: i64 = bd_why(has_offc, has_root, force_install, build_only, bd_tc, bd_dk)
  let bd_held: i64 = bd_root_held(has_root, force_install, build_only, bd_tc, bd_dk)
  has_offc = bd_writes_offc(bd_loc)
  has_root = bd_writes_root(bd_loc)
  var do_install: i64 = 0
  if bd_loc != BD_LOC_NONE { do_install = 1 }
  // A RECEIPT MUST NAME THE CONSEQUENCE, AND AN UNWRITTEN LIVE BINARY IS A RESULT, NOT AN ABSENCE.
  // Silence here is exactly what let the queued-build class run unnoticed for weeks: the only way to
  // learn what a build had done to the serving root was to hash it afterwards and compare.
  if bd_held == 1 {
      sbr_puts("[nx_sov_build_run] " as *u8); sbr_puts(name)
      sbr_puts(": SERVING-ROOT TWIN HELD -- a live binary exists at " as *u8); sbr_puts(rootpath)
      sbr_puts(" and was deliberately NOT written.\n" as *u8)
      if bd_reason == BD_WHY_BUILD_ONLY {
          sbr_puts("  REASON: --build-only. This build installed NOTHING, anywhere. AWAITING PROMOTE.\n" as *u8)
          sbr_puts("  Ship it deliberately with nx_organ_ship <target>, which runs the content ruler, the\n" as *u8)
          sbr_puts("  behaviour probe and the gate BEFORE it promotes. Do not re-run this builder without\n" as *u8)
          sbr_puts("  the flag to apply it -- that is a deploy with none of those guards.\n" as *u8)
      }
      if bd_dk == 1 {
          sbr_puts("  REASON: this target is a DECLARED DAEMON. The supervisor respawns from disk, so that\n" as *u8)
          sbr_puts("  write IS a deploy -- no canary, no health gate, no .prev. Deploy it deliberately via\n" as *u8)
          sbr_puts("  POST /api/deploy (validated, .prev-banked, async health probe + auto-rollback).\n" as *u8)
      }
      sbr_puts("  Staged artifact: " as *u8); sbr_puts(elfpath); sbr_puts("\n" as *u8)
  }
  // ⚠⚠TOOLCHAIN IS NEVER AUTO-INSTALLED (rule 26, added 2026-07-30 after seq1464; RESTORED in the
  // 2026-08-03 fork merge -- the NAS branch had dropped this entire guard, so any successful build
  // of a toolchain binary silently replaced the deployed one, canary-less, even under --build-only).
  // MEASURED INCIDENT: buildroot/_offc/nx_cc_sovereign.elf was found LIVE at 520103 bytes -- the
  // output of a rebuild made while buildroot was stale -- instead of the 543126 that had been
  // deliberately promoted. The hub was therefore compiling EVERY organ with a compiler whose
  // optimiser was 11712 source-bytes short, and its .s came out 16430B larger from identical
  // sources. Nobody chose that; a build installed it.
  //
  // THE INVARIANT: refresh-IF-PRESENT is right for ordinary organs (it retires LM-026 staleness) and
  // CATASTROPHIC for the toolchain, because the toolchain is what BUILT the thing being installed --
  // a bad build then replaces the compiler that produced it and every subsequent build inherits the
  // damage, with no promote, no canary and no .prev. That is a self-modifying build path.
  // The toolchain has exactly ONE lawful update route: /api/promote_toolchain, which ELF-validates,
  // banks .prev, chmod +x, CANARY-COMPILES AND RUNS, and auto-rolls-back. This guard makes that route
  // the only one BY CONSTRUCTION rather than by convention.
  // ★Applies to --install too: an explicit flag must not be able to brick the toolchain either.
  if bd_tc == 1 {
      if bd_would == 1 {
          sbr_puts("[nx_sov_build_run] " as *u8); sbr_puts(name)
          sbr_puts(": REFUSED to auto-install a TOOLCHAIN binary into _offc (rule 26 / seq1464).\n" as *u8)
          sbr_puts("  The build artifact is staged and usable; promote it deliberately via\n" as *u8)
          sbr_puts("  POST /api/promote_toolchain (ELF-validated, .prev-banked, canary-run, auto-rollback).\n" as *u8)
      }
      do_install = 0
  }
  if do_install == 1 {
      let il: *i64 = sys_mmap(16) as *i64
      let ib: *u8 = sys_read_file(elfpath, il)
      if (ib as i64) != 0 {
          // Refresh EVERY consumer location that actually holds a twin -- an organ forked from the
          // serving root got nothing when only _offc was refreshed.  Both writes are atomic
          // (.sbrtmp + renameat), so neither can leave a torn binary.
          if has_offc == 1 {
              let otmp: *u8 = sys_mmap(256); var oo: i64 = 0
              oo = sbr_cat(otmp, oo, offc_pfx); oo = sbr_cat(otmp, oo, name); oo = sbr_cat(otmp, oo, ".elf.sbrtmp" as *u8); otmp[oo] = 0 as u8
              let ofd: i64 = sys_openat_wr(otmp, 493)      // 0755 = executable (refresh AND force-install-new)
              if ofd >= 0 { sys_write(ofd, ib, il[0]); sys_close(ofd); sys_renameat(otmp, offcpath) }
          }
          if has_root == 1 {
              // has_root SURVIVED bd_locations, so this target is provably NOT a declared daemon, not
              // the toolchain, and the caller's intent permits an install. The daemon refusal moved up
              // to the held-twin reasons, where it prints even when nothing is installed at all --
              // down here it could only ever speak on a path that had already decided to write.
              let rtmp: *u8 = sys_mmap(256); var rr: i64 = 0
              rr = sbr_cat(rtmp, rr, root_pfx); rr = sbr_cat(rtmp, rr, name); rr = sbr_cat(rtmp, rr, ".elf.sbrtmp" as *u8); rtmp[rr] = 0 as u8
              let rfd: i64 = sys_openat_wr(rtmp, 493)
              if rfd >= 0 { sys_write(rfd, ib, il[0]); sys_close(rfd); sys_renameat(rtmp, rootpath) }
              // Say DEPLOYED, not REFRESHED. The old word is why a caller who had decided not to
              // deploy read this line and believed nothing had shipped.
              //   ★ A RECEIPT MUST NAME THE CONSEQUENCE, NOT THE MECHANISM.
              sbr_puts("[nx_sov_build_run] " as *u8); sbr_puts(name)
              sbr_puts(": DEPLOYED to serving root (twin refresh, live for the next fork) -> " as *u8)
              sbr_puts(rootpath); sbr_puts("\n" as *u8)
              if bd_dk < 0 {
                  sbr_puts("  ⚠ daemon-check UNPROVEN: knowledge/status/organ_kind.conf unreadable, so\n" as *u8)
                  sbr_puts("    this target's kind was never established. Verify it is not a daemon.\n" as *u8)
              }
          }
          // Print the path that was ACTUALLY written, not a hardcoded one.  The old message said
          // "_offc/<name>.elf" unconditionally while writing buildroot/_offc/<name>.elf, so the
          // receipt could not be used to check the claim.  VERIFY BY ARTIFACT, AND LET THE RECEIPT
          // NAME THE ARTIFACT IT WROTE.
          if force_install == 1 { sbr_puts("[nx_sov_build_run] " as *u8); sbr_puts(name); sbr_puts(": INSTALLED -> " as *u8); sbr_puts(offcpath); sbr_puts(" (--install)\n" as *u8) }
      }
  }
1794
  // release the per-target build lock HERE -- artifacts are final (atomic renames done); the run
  // phase below must not hold it (a daemon target would wedge every future rebuild of itself).
  if lockfd >= 0 { sys_flock(lockfd, SYS_LOCK_UN); sys_close(lockfd) }
1798
  // ---- build-only mode: argv[2] starting "--b" (--build-only) SKIPS the run, so a sovereign
  // bring-up/supervisor can build a dependency without triggering its side effects (e.g. a worker
  // would otherwise start a live download). The build path above is byte-for-byte unchanged;
  // this only short-circuits before the run. Default (no 2nd arg) behaves exactly as before. ----
  // --build-only OR --install both SKIP the run (skip_run was set from argv[2] at the top).
  if skip_run == 1 {
      // ARTIFACT PATH IS PART OF THE OUTPUT CONTRACT (2026-07-30). --build-only used to print only
      // "asm=NNNNB", so the caller was told the build SUCCEEDED but not WHERE the ELF landed -- and the
      // header comments still said /tmp/<name>.sov.elf while the code has written _build/<name>.sov.elf
      // since the flock change. Every caller therefore had to go hunting (measured: 3 shell round-trips
      // to locate one artifact). A tool that produces a file MUST say where it put it; the run path
      // below already prints elf=<path>, so build-only was the odd one out. Same line shape as the run
      // branch so existing log scrapers see a superset, never a changed field (rule 19).
      sbr_puts("[nx_sov_build_run] " as *u8); sbr_puts(name); sbr_puts(": asm=" as *u8); sbr_putn(asmbytes)
      sbr_puts("B  SOVEREIGN build (nx_cc->nxasm_x86, no gcc, no run)  elf=" as *u8); sbr_puts(elfpath)
      sbr_puts("\n" as *u8)
      sys_exit(SBR_OK); return SBR_OK
  }
1817
  // ---- run the sovereign ELF WITH FORWARDED ARGS; report; exit with its code ----
  // ARG-FORWARDING (2026-07-14 debt-eat): argv[fwd_start..argc) pass through to the built program, so a
  // daemon/tool builds AND launches with its runtime args in one command (e.g. a cap-secret path). Before
  // this, extra args were silently DROPPED -- caught live when the self-gated git server ran AUTH OFF.
  let rr: *i64 = sys_mmap(8 * 20) as *i64
  rr[0] = elfpath as i64
  var ra: i64 = 1
  var ai: i64 = fwd_start
  while ai < argc { if ra < 19 { rr[ra] = argv[ai]; ra = ra + 1 } ai = ai + 1 }
  rr[ra] = 0
  // NO DEADLINE HERE, deliberately: this runs the BUILT PROGRAM, which may be a daemon or a long
  // job. Time-boxing a build tool is safety; time-boxing the user's program is a wrong answer.
  let rc_r: i64 = sbr_run(elfpath, rr, envp, 0 - 1, 0 - 1, SBR_NO_DEADLINE)
  sbr_puts("[nx_sov_build_run] " as *u8); sbr_puts(name); sbr_puts(": asm=" as *u8); sbr_putn(asmbytes)
  sbr_puts("B  SOVEREIGN(nx_cc->nxasm_x86, no gcc)  elf=" as *u8); sbr_puts(elfpath)
  sbr_puts("  run-exit=" as *u8); sbr_putn(rc_r); sbr_puts("\n" as *u8)
  sys_exit(rc_r)
  return rc_r
1836}
nx_sbr_key_candidate.nx source

`nx_sbr_key_candidate.nx` source
