Language: define('LIT') inside function warns Constant already defined — Zend silent (re-#204, zend_builtin_functions.c)

[PurHur]

Category

Language · php-src-strict / define() compile-time prescan

Problem

define('NAME', literal) inside a user function (or method) emits Constant NAME already defined on VM/JIT. Zend 8.2.32 registers the constant once and is silent.

Top-level define('NAME', literal) and define($runtimeName, literal) already match Zend. The extra warning is the compile-time prescan (Compiler::prescanDefineFuncCall / storeCompileTimeGlobalConst, issue #204) seeding the constant, then the still-emitted runtime define() / TYPE_DECLARE_GLOBAL_CONST trying again when the function runs.

Probed 2026-08-18 @ 87cba84dc2 — Zend 8.2.32 vs php bin/vm.php / php bin/jit.php.

Repro	Zend 8.2.32	VM/JIT
function f() { define('C', 1); } f();	silent; defined('C')===true	Warning: Constant C already defined (attributed to the call site of f(), not the define() line)
file-scope define('C', 1);	silent	silent ✓
define('C'.'X', 1); (runtime name)	silent	silent ✓

php-src reference

• php/php-src Zend/zend_builtin_functions.c — PHP_FUNCTION(define) / zend_register_constant
• php/php-src Zend/zend_constants.c — user constants are registered when define() executes, not when the containing function is compiled

PHP implementation target

• lib/Compiler.php — prescanDefineFuncCall / tryCompileDefineAsGlobalConst: do not seed the runtime constant table for define() that will still run inside a function body; either elide the runtime call xor skip prescan, never both
• ext/standard/define_.php — runtime define() should remain the php-src-strict path for non-elided calls
• lib/VM.php TYPE_DECLARE_GLOBAL_CONST — same uniqueness as Zend zend_register_constant
• No new runtime/*.c

Repro

./script/docker-exec.sh -- bash -lc 'php bin/vm.php test/repro/maintainer_gap_define_inside_function.php'
./script/docker-exec.sh -- bash -lc 'php bin/jit.php test/repro/maintainer_gap_define_inside_function.php'
./script/docker-exec.sh -- bash -lc 'php test/repro/maintainer_gap_define_inside_function.php'  # Zend baseline

<?php
error_reporting(E_ALL);
function probe_define(): void
{
    define('PROBE_C_ISOLATED', 1);
    echo 'defined_ci=', var_export(defined('probe_c_isolated'), true), "\n";
    echo 'defined_CS=', var_export(defined('PROBE_C_ISOLATED'), true), "\n";
}
probe_define();

Done when

• VM/JIT: define('LIT', …) inside a function/method is silent on first execution (Zend); second call still warns already defined
• File-scope and runtime-name define() unchanged (already green)
• defined('LIT') / constant('LIT') still see the value after the first call
• Compliance .phpt under test/compliance/cases/language/
• php-src-strict; no php-compiler-strict shortcut that leaves the runtime define() in the function and pre-registers the constant

[PurHur]

claim: PHP Compiler Worker Lane C — starting this run

[PurHur]

Merged #32058

Fix: define('LIT') inside a function was re-emitted as TYPE_DECLARE_GLOBAL_CONST when later defined()/var_export() replayed statement-level side effects (emittedFuncCallOpcodesForCfgStmt only looked for FUNCCALL_INIT). Nested define() is also no longer seeded into compileTimeGlobalConsts before the function runs.

Verification

./script/docker-exec.sh -- bash -lc 'php bin/vm.php test/repro/maintainer_gap_define_inside_function.php'
# defined_ci=false / defined_CS=true — no Warning (matches Zend)

./script/docker-exec.sh -- bash -lc 'php bin/jit.php test/repro/maintainer_gap_define_inside_function.php'
# same

./script/phpunit.sh --filter 'DefineInsideFunction32039|Issue32039DefineInsideFunction'
# OK (5 tests, 14 assertions)

Second call still warns Constant already defined (php-src-strict). File-scope define() unchanged.