AOT: static property ??= not stored — readback NULL (re-#31965, zend_static_variable)

[PurHur]

Category

Language · php-src-strict / AOT static property storage

Problem

Null-coalescing assignment to an uninitialized static property (C::$x ??= 7) must store and return the RHS like Zend. VM/JIT match Zend; AOT probe from the static-property differential hunt leaves the property unset and reads back NULL.

Probed 2026-08-18 @ 5243c6f5e5 — Zend 8.2.32 vs php bin/vm.php (VM green). AOT probe-reported from #31965 / docs/roadmap/AOT-CORRECTNESS-PLAN.md group 3 — not re-verified this run (single-file bin/compile.php exceeded 120s compile budget on a warm cache).

Repro	Zend 8.2.32	VM	AOT (probe-reported)
C::$x ??= 7; var_dump(C::$x); twice	int(7) both times	int(7) both times	NULL (not stored)

php-src reference

• php/php-src Zend/zend_execute.c — ZEND_ASSIGN_OP / ZEND_COALESCE on static properties
• php/php-src Zend/zend_compile.c — static property fetch/write lvalues

PHP implementation target

• lib/JIT.php / lib/AOT/ — static property ??= lowering must mark module init / persist store like ordinary static writes (AOT: static property assign from closure must use module globals (#31965) #31986 typed-static closure path)
• Reuse staticPropertyStore / native-scalar static lvalue routing from AOT: static property assign from closure must use module globals (#31965) #31986 where applicable
• No new runtime/*.c

Repro

./script/docker-exec.sh -- bash -lc 'php bin/vm.php test/repro/maintainer_gap_static_coalesce_assign.php'
./script/docker-exec.sh -- bash -lc 'php test/repro/maintainer_gap_static_coalesce_assign.php'
# AOT (slow — run on idle box):
./script/docker-exec.sh -- bash -lc 'php bin/compile.php -o /tmp/static_ca test/repro/maintainer_gap_static_coalesce_assign.php && /tmp/static_ca'

Done when

• AOT: ??= on uninitialized static property stores value; repeated read returns int(7) matching Zend
• VM/JIT unchanged green
• Compliance or AOT PHPT with @differential-repeat guard
• php-src-strict; no php-compiler-strict shortcut
• Reproduce on current master before closing (probe-reported until then)

[PurHur]

claim: compile/link automation — starting this run

[PurHur]

claim: PHP Compiler Worker Lane B — starting this run

[PurHur]

Maintainer note: this issue has two claim: comments on the same run (compile/link automation, then Worker Lane B). One of you should drop the claim if you are not actually working it so the other can finish.

[PurHur]

merged: #32043 (8d640a9b89)

Fix: AOT Class::$x ??= 7 now stores via staticPropertyGlobal before the ??= merge temp is promoted to a stack slot. Master AOT readback was NULL (typed: uninitialized Error); after the fix both untyped and typed match Zend int(7).

Verification

• ./script/docker-exec.sh -- bash -lc 'php bin/vm.php test/repro/maintainer_gap_static_coalesce_assign.php' → six int(7)/int(3) lines
• php bin/compile.php -o /tmp/static_ca test/repro/maintainer_gap_static_coalesce_assign.php && /tmp/static_ca → same, exit 0
• ./script/phpunit.sh --filter StaticPropertyCoalesceAssign32035 → OK (2 tests, 25 assertions) including AOT 10×
• ./script/phpunit.sh --filter static_property_coalesce_assign_32035 → OK (VMTest + AotTest fixture)

php-src-strict. No runtime/*.c. bin/jit.php of this snippet still fails module verify on master (pre-existing; not this change).