nx_gk_fixture_gate.nx source

1// nx_gk_fixture_gate.nx -- THE REFEREE FOR gk_fixture_dir, the per-RUN gate fixture directory (2026-09-03). 2// 3// THE DEFECT IT GUARDS, measured the day it shipped. Two runs of nx_bck_elide_gate launched in the same 4// second against two DIFFERENT compilers BOTH returned verdict=SKIP with "the named compiler built none of 5// the fixtures". Neither run was faulty; the pass under test was working (its own log showed 6// BCK-ELIDE sites=4 elided=2 throughout). They had overwritten each other's fixtures in the single 7// directory both had hardcoded. Run sequentially, the same gate on the same box is 13/13 GREEN. 8// 9// The estate already enforced the PER-GATE half of this law (gate scratch in /tmp/<gate>/, never shared 10// with a production beat). The PER-RUN half did not exist, and its absence fails in the ABSTAINING 11// direction -- a false SKIP acquits nothing and alarms nobody, it just deletes the evidence. 12// 13// THE ANTI-VACUITY PROBLEM THIS GATE HAD TO SOLVE. A tooth saying "gk_fixture_dir returned a path" passes 14// for a function that returns a CONSTANT, which is precisely the broken shape. So the load-bearing tooth is 15// that TWO calls differ, and it is paired with a NEGATIVE CONTROL that builds the OLD constant-path shape by 16// hand and asserts it COLLIDES. Without that control a reader cannot tell a working discriminator from a 17// test that could never fail. 18// 19// exit: 0 GREEN . 1 RED license_tier: ORIGINAL No hw writes. 20import "nx_syscalls.nx" 21import "nx_gate_verdict.nx" 22import "nx_gatekit_lib.nx" 23 24const GF_PATH: i64 = 1024 25const GF_SUBJECT: *u8 = "nx_gk_fixture_gate_subject" 26 27func gf_streq(a: *u8, b: *u8) -> i64 { 28 var i: i64 = 0 29 while a[i] != (0 as u8) { if a[i] != b[i] { return 0 } i = i + 1 } 30 if b[i] != (0 as u8) { return 0 } 31 return 1 32} 33 34func main(argc: i64, argv: *i64) -> i64 { 35 let ctr: *i64 = gv_ctr() 36 gv_head("NX-GK-FIXTURE-GATE: a gate fixture dir is per-RUN, so two concurrent runs of one gate cannot collide" as *u8) 37 38 let a: *u8 = sys_mmap(GF_PATH) 39 let b: *u8 = sys_mmap(GF_PATH) 40 let na: i64 = gk_fixture_dir(GF_SUBJECT, a) 41 let nb: i64 = gk_fixture_dir(GF_SUBJECT, b) 42 43 gv_puts(" dir_a=" as *u8); gv_puts(a); gv_puts("\n" as *u8) 44 gv_puts(" dir_b=" as *u8); gv_puts(b); gv_puts("\n" as *u8) 45 46 // the fixture must actually have reached its condition before any outcome is asserted 47 gv_check("fixture-reached-the-condition-both-dirs-were-created-on-disk" as *u8, (gk_exists(a) as i64) & (gk_exists(b) as i64), ctr) 48 gv_check_eq("both-calls-returned-a-nonempty-path" as *u8, ((na > 0) as i64) + ((nb > 0) as i64), 2, ctr) 49 gv_check("the-dir-is-named-for-its-gate-so-an-operator-can-find-it" as *u8, gk_has(a, GF_SUBJECT), ctr) 50 gv_check("the-dir-is-under-tmp-never-in-the-knowledge-tree" as *u8, gk_has(a, "/tmp/" as *u8), ctr) 51 52 // THE LOAD-BEARING TOOTH: a discriminator that returns the same thing twice is the bug, not the fix 53 let differ: i64 = 1 - gf_streq(a, b) 54 gv_check_eq("TWO-CALLS-IN-ONE-PROCESS-YIELD-DIFFERENT-DIRS-the-whole-point" as *u8, differ, 1, ctr) 55 56 // NEGATIVE CONTROL: reconstruct the OLD constant-path shape and prove it collides. Without this a 57 // reader cannot distinguish a working discriminator from a tooth that could never fire. 58 let c1: *u8 = sys_mmap(GF_PATH) 59 let c2: *u8 = sys_mmap(GF_PATH) 60 gk_cat(c1, 0, "/tmp/" as *u8); gk_cat(c1, gk_len(c1), GF_SUBJECT) 61 gk_cat(c2, 0, "/tmp/" as *u8); gk_cat(c2, gk_len(c2), GF_SUBJECT) 62 let collides: i64 = gf_streq(c1, c2) 63 gv_check_eq("neg-control-the-OLD-constant-path-shape-DOES-collide-so-this-suite-can-fail" as *u8, collides, 1, ctr) 64 gv_bite("bite-the-per-run-dir-separates-two-runs-while-the-constant-path-does-not" as *u8, collides, 1 - differ, ctr) 65 66 gv_kv("dir_len_a" as *u8, na) 67 gv_kv("dir_len_b" as *u8, nb) 68 gv_kv("dirs_differ" as *u8, differ) 69 gv_kv("constant_shape_collides" as *u8, collides) 70 71 return gv_verdict("nx_gk_fixture_gate" as *u8, ctr, "two calls in one process yield distinct created dirs, and the constant-path shape it replaces is proven to collide" as *u8) 72}