Stdlib: internal string function numeric coercion — strpos/str_contains vs strlen (ext/standard/string.c parity)

[PurHur]

Category

stdlib / runtime

Problem

Zend coerces scalar operands to string for many internal string functions via zend_parse_parameters / _convert_to_string(). This compiler is inconsistent:

Call	Zend PHP 8.x	This compiler
strlen(123)	3	3 ✅
str_contains(123, '2')	true	LogicException ❌
strpos(123, '2')	1	LogicException ❌

Strict string-only checks in ext/standard/str_contains.php and strpos.php diverge from php-src.

php-src reference

• ext/standard/string.c — PHP_FUNCTION(str_contains), PHP_FUNCTION(strpos) parameter parsing with string coercion
• Zend/zend_operators.c — _convert_to_string(), convert_to_string() on zvals
• ext/standard/basic_functions.c — shared parse_str helpers

Repro (today)

<?php
var_export(str_contains(123, '2'));
echo "\n";
var_export(strpos(123, '2'));
echo "\n";
echo strlen(123), "\n";

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && ./script/apply-patches.sh >/dev/null && php bin/vm.php repro.php'
php repro.php

Expected (Zend): true, 1, 3
This compiler: fatal on str_contains / strpos.

Scope (this repo)

Module	Path
VM helpers	ext/standard/VmString.php — shared coerceToString() used by string builtins
Stdlib	ext/standard/str_contains.php, strpos.php, audit siblings (stripos, str_starts_with, …)
JIT	mirror coercion in lib/JIT/Builtin/Standard/ stubs or defer with matrix note
Tests	test/compliance/cases/stdlib/string_coerce_numeric.phpt

Done when

• Repro matches Zend output on VM
• Audit of PHP 8 string search/compare builtins uses same coercion policy as php-src (document exceptions like strcmp strictness)
• ./script/ci-fast.sh --filter StringCoerce green
• docs/capabilities.md notes coercion behavior where non-obvious

Links

• (string) object cast / __toString: Language: (string) object cast must invoke __toString (Zend zend_operators.c parity) #3421
• North star: Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492

[PurHur]

claim: cursor-agent-lane-a — starting this run

[PurHur]

Merged via PR #3978.

Verification:

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && ./vendor/bin/phpunit test/compliance/VMTest.php --filter string_coerce_numeric'
# OK (1 test, 1 assertion)

VM repro (str_contains(123,'2'), strpos(123,'2'), strlen(123)) now matches Zend: true, 1, 3.