Language: $GLOBALS[] = compiles — Zend Cannot append to $GLOBALS (re-#32229, Zend/zend_compile.c)

[PurHur]

Category

language · php-src-strict · compile-time fatal · $GLOBALS[] append (sibling of closed #32229)

Problem

Appending to $GLOBALS with empty dim ($GLOBALS[] = 1) compiles and runs (rc=0). Zend 8.1+ is a compile-time fatal with a distinct sentence from wholesale assign:

Cannot append to $GLOBALS

#32229 (closed) covered $GLOBALS = [], $GLOBALS += …, and unset($GLOBALS) → $GLOBALS can only be modified using the $GLOBALS[$name] = $value syntax. Indexed $GLOBALS['x'] = 1 is valid on both sides (control). Empty-dim append is a separate zend_compile_assign_dim check and is still accepted here.

Verified 2026-08-18 @ dda76adf48 vs Zend 8.2.32.

Repro	Zend 8.2.32	VM / JIT
$GLOBALS[] = 1; echo "accepted";	Fatal Cannot append to $GLOBALS (rc=255)	accepted (rc=0)
$GLOBALS['x'] = 1; (control)	rc=0	rc=0
$GLOBALS = []; (control, #32229)	Fatal $GLOBALS can only be modified using the $GLOBALS[$name] = $value syntax	should already match after #32229

php-src reference

• php/php-src Zend/zend_compile.c — zend_compile_assign_dim() when the variable is $GLOBALS and the dim is omitted ([]) → Cannot append to $GLOBALS
• PHP 8.1 “Restrict $GLOBALS” RFC; indexed $GLOBALS[$name] remains the only legal write; append is never legal

PHP implementation target

• lib/Compiler.php — next to rejectGlobalsReferenceAcquisition() (Language: $ref = &$GLOBALS must compile-time fatal — VM executes (Zend/zend_compile.c) #15627) / Language: $GLOBALS = [] compiles — Zend can only be modified using $GLOBALS[$name] syntax (Zend/zend_compile.c) #32229 assign/unset: when compiling dim-assign/append, if the base name is GLOBALS and the dim is empty/null, throwCompileError('Cannot append to $GLOBALS')
• Do not reuse the Language: $GLOBALS = [] compiles — Zend can only be modified using $GLOBALS[$name] syntax (Zend/zend_compile.c) #32229 “can only be modified using $GLOBALS[$name]” string — Zend’s append diagnostic is different
• Same compile path for JIT/AOT; no new runtime/*.c logic

Repro

./script/docker-exec.sh -- bash -lc 'php bin/vm.php test/repro/maintainer_gap_globals_append.php 2>&1 | head -5'
./script/docker-exec.sh -- bash -lc 'php bin/jit.php test/repro/maintainer_gap_globals_append.php 2>&1 | head -5'

<?php
$GLOBALS[] = 1;
echo "accepted\n";

Done when

• VM and JIT compile-abort with Zend substring Cannot append to $GLOBALS (never print accepted)
• $GLOBALS['x'] = 1 still succeeds; #32229 assign/+=/unset($GLOBALS) messages unchanged
• Compliance .phpt guard under test/compliance/cases/language/
• php-src-strict; no php-compiler-strict shortcut

[PurHur]

claim: Worker lane A — starting this run

[PurHur]

Merged #32268

VM and JIT now compile-abort $GLOBALS[] = 1 with Zend Cannot append to $GLOBALS (rc=255); never prints accepted. Indexed $GLOBALS['x'] = 1 and $GLOBALS['x'][] still succeed; #32229 assign/+=/unset($GLOBALS) messages unchanged.

Verification:

• php bin/vm.php test/repro/maintainer_gap_globals_append.php → PHP Fatal error: Cannot append to $GLOBALS rc=255
• php bin/jit.php test/repro/maintainer_gap_globals_append.php → same, rc=255
• ./script/phpunit.sh --filter GlobalsWriteCompileFatalTest → OK (15 tests)
• ./script/phpunit.sh --filter GlobalsWrite32229 → OK (12 tests, VM+JIT)

PHP implementation: lib/Compiler.php rejectGlobalsAppend() next to #32229 rejectGlobalsWrite(). php-src: Zend/zend_compile.c zend_compile_assign_dim().