Language: internal builtin exceptions must honor user try/catch (zend_exceptions.c)

[PurHur]

Category

language · runtime · stdlib bridge

Problem

User try/catch blocks must intercept exceptions thrown from internal/builtin handlers the same way Zend does. Today:

1. ValueError from builtins can be swallowed — substr_compare(..., -1) inside catch (ValueError) prints no throw and exits 0 on VM, while Zend catches.
2. LogicException/TypeError from builtins ignore catch blocks — floor($object) inside catch (TypeError) either fatals through the handler (LogicException path) or silently continues (no throw), never entering the user catch.

Bare throw new ValueError(...) is catchable (probe14e green), so the bug is specific to exceptions raised from Internal::execute() / VM dispatch, not the catch machinery itself.

Related umbrella: #4178 (wrong exception type from builtins) — fix types and ensure they propagate into active catch frames.

php-src reference

• php/php-src Zend/zend_exceptions.c — zend_throw_exception_internal, active try_catch_array
• php/php-src Zend/zend_execute.c — ZEND_HANDLE_EXCEPTION

Repro

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php test/repro-maintainer/parity_builtin_try_catch.php; echo zend:$?
php bin/vm.php test/repro-maintainer/parity_builtin_try_catch.php; echo vm:$?
'

Case	Zend	VM
substr_compare negative length in catch (ValueError)	caught ValueError	no throw
floor(object) in catch (TypeError)	caught TypeError	no throw

Repro script: test/repro-maintainer/parity_builtin_try_catch.php

Scope (this repo)

Area	Files
VM	lib/VM.php — internal handler exception dispatch into catch stack
VM	lib/VM/ExceptionSupport.php — ValueError/TypeError bridging
Stdlib	ext/standard/*.php — after VM fix, migrate LogicException → TypeError/ValueError (#4178)
Tests	test/compliance/cases/language/builtin_try_catch.phpt

Done when

• Repro prints caught ValueError + caught TypeError on VM (exit 0)
• Uncaught builtin exceptions still fatal with exit 255 outside try
• ./script/ci-fast.sh --filter builtin_try_catch green

Links

• Stdlib: builtin wrong-type parameters — TypeError not LogicException (ext/standard parity) #4178, Stdlib: builtin argument count errors should be ArgumentCountError (not LogicException) #4145, Language: catchable Error for undefined method on objects — VM dispatch (zend_execute.c) #4851
• Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492

[PurHur]

claim: worker-lane-a — starting this run

[PurHur]

Merged via #7551

Root cause: void internal builtin calls (FUNCCALL_EXEC_NORETURN) passed returnVar = null, and many handlers early-return before validation/throws that happen after the return slot check (e.g. substr_compare() → ValueError for negative length).

Fix: executeInternalHandler() always supplies a scratch returnVar; LogicException from stdlib handlers now dispatches into active user catch frames.

Verification:

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php test/repro-maintainer/parity_builtin_try_catch.php; echo vm:$?
vendor/bin/phpunit --filter builtin_try_catch
'

→ caught ValueError + caught TypeError, exit 0; OK (4 tests, 4 assertions).