Language: asymmetric visibility private(get) / protected(get) — parse + read guards (zend_compile.c)

[PurHur]

Category

language

Problem

PHP 8.4 asymmetric property visibility includes a read side (public private(get), protected private(get), etc.), not only private(set) / protected(set) / public(set) on writes.

This repo’s lib/Ast/AsymmetricVisibilityRewriter.php rewrites set modifiers only (MARKER_PREFIX = phpc-asymmetric-set:). There is no marker or VM/JIT guard for get visibility, and no compliance coverage for private(get) / protected(get).

Zend rejects illegal read/write combinations at compile time and enforces read access in zend_object_handlers.c.

php-src reference

• php/php-src Zend/zend_compile.c — ZEND_ACC_PUBLIC_GET, ZEND_ACC_PROTECTED_GET, ZEND_ACC_PRIVATE_GET (and set counterparts)
• php/php-src Zend/zend_object_handlers.c — zend_std_read_property asymmetric checks

Repro (expected Zend vs today)

<?php
class Box {
    public private(get) string $secret = 'hidden';
}
$b = new Box();
echo $b->secret, "\n"; // global scope: Error — cannot access private(get) property

php repro.php
# Zend: Error: Cannot access private(get) property Box::$secret from global scope

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && php bin/vm.php repro.php'
# Today: likely parse/compile failure or treats as ordinary public read (parity drift)

Also verify combined forms compile when valid in Zend, e.g. public protected(set) string $x.

Scope (this repo)

Area	Path
Parse/rewrite	lib/Ast/AsymmetricVisibilityRewriter.php, lib/Runtime.php preprocessor
PHPCfg flags	lib/Compiler.php — propertySetVisibility + new get visibility storage
VM read guard	lib/VM.php — mirror asymmetricPropertyWriteMessage() for reads
JIT/AOT	lib/JIT/AsymmetricVisibilityGuard.php — read-side LLVM guard (phase 2 OK)
Tests	test/compliance/cases/language/asymmetric_visibility_private_get.phpt

Done when

• private(get) / protected(get) properties parse and compile on VM
• Illegal read from outer scope raises catchable Error matching Zend text
• Existing private(set) tests still pass (asymmetric_visibility_*.phpt)
• ./script/ci-fast.sh --filter asymmetric_visibility_private_get green

Related

• Language: PHP 8.4 asymmetric property visibility (public/private(set), etc.) #3165 (closed) — private(set) write guards · Language: asymmetric visibility on constructor-promoted properties (zend_compile.c parity) #4690 promoted properties · Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492 self-host

[PurHur]

claim: cursor-agent-lane-b — starting this run

[PurHur]

Merged via PR #6087.

Verification

./script/docker-exec.sh -- bash -lc 'php bin/vm.php -r "
class Box { public private(get) string \$secret = \"hidden\"; }
\$b = new Box();
try { echo \$b->secret; } catch (Error \$e) { echo get_class(\$e), \": \", \$e->getMessage(), \"\\n\"; }
\$b->secret = \"ok\";
echo \"set ok\\n\";
try { echo \$b->secret; } catch (Error \$e) { echo get_class(\$e), \": \", \$e->getMessage(), \"\\n\"; }
"'

Error: Cannot access private(get) property Box::$secret from global scope
set ok
Error: Cannot access private(get) property Box::$secret from global scope

./script/docker-exec.sh -- ./vendor/bin/phpunit --filter asymmetric_visibility_private_get

OK (1 test). Existing private(set) asymmetric tests still pass.