Regression: substr_compare(..., null) $case_insensitive coerces — Zend TypeError (ext/standard/string.c)

[PurHur]

Category

Regression · php-src-strict · bool param strictness · pillar 4

Problem

The optional fifth parameter $case_insensitive of substr_compare() is typed bool in php-src. Passing null must throw TypeError. VM/JIT call Variable::toBool() / JIT bool coercion and continue, returning a comparison result (0 in the probe).

This is distinct from haystack/needle soft-null on PROFILE≥8.4 (#21515, closed) — here all string/int operands are valid; only the bool argument is null.

Probed 2026-08-10 in php-compiler:22.04-dev (Zend 8.2.32, also verified under PHP_COMPILER_PROFILE=8.4).

Repro	Zend 8.2 / 8.4	VM/JIT (2026-08-10)
substr_compare('abc','ab',0,2,null)	TypeError: … $case_insensitive must be of type bool, null given	int(0) (silent coerce) ❌

php-src reference

• php/php-src ext/standard/string.c — Z_PARAM_BOOL / php_substr_compare $case_insensitive

PHP implementation target

• ext/standard/substr_compare.php — replace $ci->toBool() with strict bool check (mirror requireIntArg pattern for arg Stdlib: floatval, boolval, gettype(null) and expanded PHPT specs #5)
• lib/JIT/Builtin/StringSubstrCompare.php / SubstrCompareJitHelper.php — emit TypeErrorRaise for non-bool $case_insensitive; remove LogicException “must be boolean in this compiler build” shortcut for boxed values

Repro

./script/docker-exec.sh -- bash -lc 'php bin/vm.php test/repro/issue_substr_compare_null_ci.php'
./script/docker-exec.sh -- bash -lc 'php bin/jit.php test/repro/issue_substr_compare_null_ci.php'
./script/docker-exec.sh -- bash -lc 'php test/repro/issue_substr_compare_null_ci.php'

Done when

• VM/JIT throw the same TypeError as Zend for null/non-bool $case_insensitive
• Compliance .phpt guard under test/compliance/cases/stdlib/
• php-src-strict; no php-compiler-strict shortcut

[PurHur]

claim: PHP Compiler STD Lib — starting this run

Pillar probe (pre-implement):

• docker info: ok
• php script/bootstrap-inventory.php --check: construct-flag/doc drift only (stale docs/bootstrap-inventory.md) — not a Pillar 1 compile blocker
• release-readiness / north-star5-verify-fast: still running in background

Claiming #29756 (substr_compare null $case_insensitive → Zend TypeError). Will verify VM + AOT on the issue repro.

[PurHur]

Merged via #29787

Verification

• Zend/VM/JIT: TypeError: substr_compare(): Argument #5 ($case_insensitive) must be of type bool, null given
• AOT: bin/compile.php + binary run of test/repro/issue_substr_compare_null_ci_aot.php (same TypeError)
• Soft-null (no strict): DEP + coerce to false (SubstrCompareNullCiCoerce*)
• phpunit --filter SubstrCompareNullCi OK (4); AotTest substr_compare_null_ci_strict OK

php-src: ext/standard/string.c Z_PARAM_BOOL. PHP: ext/standard/substr_compare.php via VmMath::parseBoolBuiltinArgForFrame / JitBoolArg::lowerCoerceZParamBool.