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Regression: forward-profile builtins register on 8.2 reference — mb_trim/crc32c/hebrevc leak (ext/standard/Module.php) #17206
Description
Category
Regression · php-src-strict · profile gating / function_exists parity
Problem
On the default 8.2 reference profile (no PHP_COMPILER_PROFILE), several PHP 8.3/8.4-only builtins are registered and callable in this compiler while Zend 8.2 reports function_exists(...) === false. This breaks profile parity and lets user code detect the non-Zend runtime.
| Builtin | Zend 8.2 function_exists |
VM 8.2 (2026-07-07) |
|---|---|---|
mb_trim |
false |
true (callable) |
crc32c |
false |
true |
hebrevc |
false |
true |
attribute_exists |
false |
true |
class_uses_recursive |
false |
true |
php-src reference
- php/php-src
ext/standard/basic_functions.c—attribute_exists(8.4) - php/php-src
ext/standard/crc32.c—crc32c(8.3) - php/php-src
ext/standard/string.c—hebrevc(8.3) - php/php-src
ext/mbstring/mbstring.c—mb_trim/mb_ltrim/mb_rtrim(8.4) - php/php-src
ext/standard/basic_functions.c—class_uses_recursive(8.3)
PHP implementation target
ext/standard/Module.php,ext/mbstring/Module.php— gate registration onCompilerVersionprofile helpers (same pattern assupportsListDestructuringSpreadAssign())lib/CompilerVersion.php— centralize per-builtin profile predicates; avoid orphanfunction_existsentries- JIT/AOT builtin tables must respect the same gates
Repro
./script/docker-exec.sh -- bash -lc 'php bin/vm.php test/repro/maintainer_gap_forward_profile_builtin_leak_82.php'
# VM: fail lists leaked symbols; Zend-equivalent profile should print ok
./script/docker-exec.sh -- bash -lc 'php -r "var_dump(function_exists(\"mb_trim\"));"; php bin/vm.php -r "var_dump(function_exists(\"mb_trim\"));"'Done when
- Default 8.2 reference profile:
function_existsfalse and call fatals/undefined functionfor all listed builtins -
PHP_COMPILER_PROFILE=8.4(or forward profile): builtins register and pass existing forward repros (maintainer_gap_mb_trim_function_exists_forward_84.php,maintainer_gap_crc32c_builtin.php, etc.) - Compliance guard under
test/compliance/cases/stdlib/profile_gate/ - php-src-strict; no php-compiler-strict shortcut
Activity
PurHur commentedon Jul 7, 2026
claim: cursor-agent-lane-b — starting this run
Fix forward-profile builtin leak on 8.2 reference profile (#17206) (#…
PurHur commentedon Jul 7, 2026
Merged via #17212.
Verification (reference profile):
php bin/vm.php test/repro/maintainer_gap_forward_profile_builtin_leak_82.php→okfunction_exists('mb_trim')bothfalseon unsetPHP_COMPILER_PROFILEForward profile preserved:
PHP_COMPILER_PROFILE=8.4repros formb_trim,crc32cgreenCompliance guard:
test/compliance/cases/stdlib/profile_gate/forward_profile_builtin_leak_82.phptPurHur commentedon Jul 7, 2026
claim: PHP Compiler STD Lib — starting this run
Merge origin/master into agent/issue-17206-forward-profile-builtin-leak
PurHur commentedon Jul 7, 2026
Merged via #17212 — forward-profile builtins (
mb_trim,crc32c,hebrevc,attribute_exists,class_uses_recursive) no longer leak on unset 8.2 reference profile.Verification (master):
```bash
./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && php bin/vm.php test/repro/maintainer_gap_forward_profile_builtin_leak_82.php'
ok
./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && php bin/vm.php -r "var_dump(function_exists("mb_trim"), function_exists("crc32c"), function_exists("hebrevc"), function_exists("attribute_exists"), function_exists("class_uses_recursive"));"'
bool(false) x5
```
chore: drop stale maintainer_gap repros + note branch hygiene (jul08 …