Language: asymmetric visibility — explicit read+set modifiers wrongly compile-fatal (regression vs #7099, PHP 8.4 RFC)

[PurHur]

Category

language

Problem

PHP 8.4 asymmetric property visibility allows explicit read + set modifiers on the same property, e.g. public private(set) string $name (equivalent to shorthand private(set) string $name). Zend accepts public protected(set) and protected private(set) as well.

Closed #7099 added compile-time rejection in lib/Ast/AsymmetricVisibilityRewriter.php (rejectExplicitReadBeforeAsymmetricSetModifier()), but that diverges from php-src / the RFC: valid PHP 8.4 sources now fail with:

Multiple access type modifiers are not allowed

Shorthand private(set) alone still compiles (#3165).

php-src-strict: illegal combos such as protected public(set) must remain compile fatals.

php-src reference

• php/php-src Zend/zend_compile.c — asymmetric visibility flags
• php/php-src Zend/zend_language_parser.y — property_modifier grammar
• PHP RFC: Asymmetric Visibility v2
• PHP manual: Visibility — Asymmetric Property Visibility

Repro (failure today)

<?php
class A {
    public private(set) string $x = 'a';
}
class B {
    public protected(set) string $y = 'b';
}
class C {
    protected private(set) string $z = 'c';
}
echo "compiled\n";

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php bin/vm.php repro.php; echo vm_exit=$?
# Compare on PHP 8.4+ reference build when available
'

Observed (VM): parseAndCompile failure: Multiple access type modifiers are not allowed for all three classes.

Expected (php-src 8.4): compiles; read/write scopes enforced at runtime.

Implementation hints (PHP-in-PHP)

• Fix lib/Ast/AsymmetricVisibilityRewriter.php: stop rejecting valid read + set(set) pairs; keep rejecting set more permissive than get (e.g. protected public(set)).
• Preserve PHPCfg markers consumed by lib/JIT/Builtin/Type/Object_.php asymmetric set tables (Language: PHP 8.4 asymmetric property visibility (public/private(set), etc.) #3165, Language: asymmetric visibility on interface properties — compile + VM set guard (PHP 8.4, zend_compile.c) #4876).
• Add compliance cases under test/compliance/cases/language/asymmetric_visibility_explicit_modifiers.phpt.

Pairs

• Regression of closed Language: asymmetric visibility — public+private(set)/public+protected(set) must compile fatal (zend_compile.c) #7099 (incorrect php-src interpretation)
• Runtime enforcement already partially present in lib/VM.php (Language: PHP 8.4 asymmetric property visibility (public/private(set), etc.) #3165, Language: property hooks with asymmetric set visibility set (protected) => — parse fails (zend_property_hooks.c) #6898)

[PurHur]

claim: worker-lane-c — starting this run

[PurHur]

Merged via #7325.

Fix: Removed incorrect #7099 blanket rejection of explicit read+set modifier pairs in AsymmetricVisibilityRewriter. Valid PHP 8.4 forms (public private(set), public protected(set), protected private(set), parenthesized variants) now compile; illegal set-more-permissive-than-read combos still fail in AsymmetricVisibilityCompileCheck.

Verification:

• Issue repro: php bin/vm.php test/repro/asymmetric_visibility_explicit_modifiers_7308.php → compiled, exit 0
• Unit: AsymmetricVisibilityRewriterTest + AsymmetricVisibilityCompileCheckTest → 17 tests OK
• Compliance: asymmetric_visibility_explicit_modifiers + related VM cases → 4 tests OK