Language: isolate generator try/catch across yield (#22869)

[PurHur]

Summary

• Isolate activeTryHandlerFrames / tryMergeBlockIds across generator suspend/resume so a suspended generator try/catch cannot absorb caller uncaught exceptions (silent exit 0).
• After generator try/finally with no catch, bubble via GeneratorUncaughtThrow instead of raiseUncaughtException while still inside advance (keeps foreach caller catch working).
• Compliance PHPT + repro for uncaught Generator::getReturn() after throw→yield-in-catch.

Closes #22869

php-src reference

• Zend/zend_generators.c — zend_generator_get_return / throw→catch yield suspension

PHP implementation

• lib/VM.php — advanceGeneratorIteration try-handler isolation; resumeCatchAfterFinally generator/fiber bubble
• lib/VM/GeneratorState.php — suspendedTryHandlerFrames / suspendedTryMergeBlockIds

Test plan

• Issue repro: php bin/vm.php test/repro/issue_22869_generator_getreturn_uncaught.php → fatal + exit 255
• ./script/phpunit.sh --filter GeneratorVMTest → OK (33)
• ./script/ci-fast.sh (AOT smoke slow under host load; not required for this VM-only path)

Verification

$ php bin/vm.php test/repro/issue_22869_generator_getreturn_uncaught.php; echo exit=$?
A
1
B
2
C
PHP Fatal error:  Uncaught Exception: Cannot get return value of a generator that hasn't returned ...
exit=255

$ ./script/phpunit.sh --filter GeneratorVMTest
OK (33 tests, 36 assertions)

Trust probe (this run)

• inventory OK 6512/6512; vm-driver-probe ok
• north-star5-fast red on master (gen-0 manifest Self-host M5: bootstrap-inventory argv driver size floor — grow beyond 451KB stub #8713/Gen-1+ #1492: committed gen-0 seed cannot be rebuilt — refresh OOMs at 48 GiB, 44 restamps since the blob last changed (script/bootstrap-refresh-gen0-sidecar.sh) #22642) — unrelated; user_release_ready: no

Made with Cursor