Stdlib: strlen() Stringable object — TypeError not __toString length (ext/standard/string.c) #13468

Category

stdlib · php-src-strict

Problem

strlen($obj) on a Stringable object throws TypeError: strlen(): Argument #1 ($string) must be of type string, C given. Zend returns the byte length of the __toString() result (3 for 'obj').

Sibling builtins trim() / ltrim() / rtrim() / chop() / strtoupper() already coerce Stringable objects on VM — only strlen() rejects.

php-src reference

• ext/standard/string.c — Z_STRLEN / _php_string_arg object coercion

Repro (verified 2026-06-29)

./script/docker-exec.sh -- bash -lc '
php test/repro/maintainer-parity-probes/probe_strlen_stringable.php; echo ---;
php bin/vm.php test/repro/maintainer-parity-probes/probe_strlen_stringable.php
php test/repro/maintainer-parity-probes/probe_string_builtin_stringable.php; echo ---;
php bin/vm.php test/repro/maintainer-parity-probes/probe_string_builtin_stringable.php
'

Scope (PHP-in-PHP first)

Done when (php-src-strict)

• strlen(Stringable) returns strlen((string)$obj) result
• Object without string conversion throws Error / TypeError matching Zend
• trim family unchanged
• No new C in runtime/

Verification

./script/docker-exec.sh -- php bin/vm.php test/repro/maintainer-parity-probes/probe_strlen_stringable.php

Links

• Stdlib: str_pad() / count_chars() — TypeError for non-string operands (ext/standard/string.c parity) #4581 · Stdlib: str_word_count()/strrev()/chunk_split()/similar_text()/levenshtein()/substr_count() — enum case operands must TypeError (string.c) #8797 · Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492