`nx_term_kat.nx` source

1// nx_term_kat.nx -- KAT (known-answer test) for the unterminated-final-block
2// bug class, distilled from the nx_ttt_evaluate draw-detect miscompile
3// (2026-06-09).  The trap shape: a VOID function whose body ends with a
4// while loop that contains an early-return if.  The buggy frontend left the
5// loop-exit block (holding the post-loop stores) with NO terminator, so it
6// FELL THROUGH into the if-body block emitted after it -- the post-loop
7// stores were silently clobbered by the early-return stores.
8//
9// This KAT must stay GREEN forever.  It prints a marker AND exits 0, so it
10// is judgeable through marker-grep even on channels where $? lies (see
11// feedback-wsl-exit-code-judging-2026-06-09).
12//
13// license_tier: ORIGINAL
14import "nx_syscalls.nx"
15
16// The trap-shaped function: scan 9 cells; early-return ONGOING(0) on any
17// empty cell; post-loop (board full) store DRAW(2).  Mirrors evaluate's tail.
18func tk_scan(s: *i64) {
19    var i: i64 = 0
20    while i < 9 {
21        if s[i] == 0 {
22            s[10] = 0
23            s[11] = 0
24            return
25        }
26        i = i + 1
27    }
28    s[10] = 2
29    s[11] = 0
30}
31
32func main() -> i64 {
33    let s: *i64 = sys_mmap(8 * 12) as *i64
34
35    // Case 1: full board -> post-loop DRAW store must SURVIVE (the bug
36    // clobbered it back to 0 via fallthrough).
37    var i: i64 = 0
38    while i < 9 { s[i] = 1 + (i % 2); i = i + 1 }
39    s[10] = 0 - 1
40    tk_scan(s)
41    if s[10] != 2 { sys_write(1, "TERM-KAT FAIL case1 (draw clobbered)\n" as *u8, 37); return 1 }
42
43    // Case 2: one empty cell -> early-return ONGOING path still correct.
44    s[4] = 0
45    s[10] = 0 - 1
46    tk_scan(s)
47    if s[10] != 0 { sys_write(1, "TERM-KAT FAIL case2 (ongoing wrong)\n" as *u8, 36); return 2 }
48
49    sys_write(1, "TERM-KAT ALL-PASS\n" as *u8, 18)
50    return 0
51}
nx_term_kat.nx source

`nx_term_kat.nx` source
