Regression: throw expressions — compile aborts (PHPTypes TypeReconstructor missing Expr_Throw, reopen #3802)

[PurHur]

Category

language · php-src-strict · IMPORTANT

Problem

PHP 8.0 throw expressions (throw in ternary/??/assignment) should compile and run on the VM path (#3802, closed). On current master, every throw-expression script fails at parseAndCompile before bytecode emission:

parseAndCompile failure: … Unknown variable op found: Expr_Throw

Root cause: ircmaxell/php-types TypeReconstructor::resolveOp() has no Expr_Throw case and throws at the tail default (prelinked/bootstrap-vendor/sources/ircmaxell/php-types/lib/PHPTypes/TypeReconstructor.php). The php-cfg / lib/Compiler.php lowering from #3802 is unreachable until PHPTypes accepts the op.

This blocks #4137 (JIT) and #4041 (AOT) — both assume VM compile already works.

php-src reference

• php/php-src Zend/zend_compile.c — zend_compile_throw() in expression context
• php/php-src Zend/zend_language_parser.y — T_THROW expr

Repro (failure today)

<?php
// ternary arm
echo (false ? 1 : throw new LogicException('x'));

// assignment (PHP 8.0+)
$x = throw new Exception('e');

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php bin/vm.php -r "echo (false ? 1 : throw new LogicException(\"x\"));"'
# parseAndCompile failure: Unknown variable op found: Expr_Throw

Zend PHP 8+: uncaught exception / non-zero exit (never a compile abort).

Scope (this repo)

Layer	Path	Work
Vendor patch	patches/php-types-*.patch, script/apply-patches.sh	add Expr_Throw case (return never / bottom type)
Prelinked	prelinked/bootstrap-vendor/	regenerate after patch
Compiler	lib/Compiler.php	verify compileThrowExpression still wired (#3802)
Tests	test/compliance/cases/language/throw_expression*.phpt	VM must execute before JIT work

PHP-in-PHP first — no new runtime/*.c branches.

Done when

• Repro scripts compile under php bin/vm.php (no Unknown variable op found: Expr_Throw)
• Ternary, ??, short-circuit, and assignment throw expressions match Zend uncaught-exception behavior on VM
• ./script/ci-fast.sh --filter throw_expression green on VM group
• Language: throw expressions — JIT lowering (phase 2 of #3802) #4137 / Language: throw expressions — AOT lowering (phase 2 of #3802) #4041 unblocked for JIT/AOT follow-up

Related

• Language: throw expressions (PHP 8.0) — parse and lowering in expression context #3802 (closed VM delivery) · Language: throw expressions — JIT lowering (phase 2 of #3802) #4137 · Language: throw expressions — AOT lowering (phase 2 of #3802) #4041 · Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492

[PurHur]

claim: worker-lane-c — starting this run

[PurHur]

Merged via #6752.

Root cause: corrupt/stale php-cfg-new-ctor-parens.patch caused apply-patches.sh to exit before throw-expr overlays ran on fresh vendor — reproducing Unknown variable op found: Expr_Throw.

Fix: throw-expr overlays now run immediately after incdec (hard-required spine); Expr_Throw type-reconstructs as Type::never(); new-ctor-parens marked optional (#6549 follow-up).

Verification (green on branch):

• php bin/vm.php -r 'echo (false ? 1 : throw new LogicException("x"));' — throws LogicException (not compile abort)
• vendor/bin/phpunit --filter throw_expression — OK (6 tests)
• vendor/bin/phpunit test/unit/ApplyPatchesTest.php --filter ThrowExpr — OK (4 tests)