token_get_all(TOKEN_PARSE): class constant named with a reserved keyword is no longer retagged to T_STRING when the same keyword appears in its initializer (regression in 8.3)
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Descrizione
Description
Description
Since PHP 8.3, token_get_all($code, TOKEN_PARSE) fails to retag a reserved
keyword used as a class constant name to T_STRING when the same keyword
also appears as a class-constant fetch inside the initializer of that constant.
The code itself parses, lints and runs fine — only the tokenizer output is wrong.
<?php
$code = '<?php class Foo { public const NEW = Bar::NEW; }';
foreach (token_get_all($code, TOKEN_PARSE) as $t) {
if (is_array($t) && strcasecmp($t[1], 'new') === 0) {
echo token_name($t[0]), ' [', $t[1], ']', PHP_EOL;
}
}
Resulted in this output (PHP 8.3, 8.4, 8.5):
T_NEW [NEW] <-- declaration: NOT retagged (bug)
T_STRING [NEW] <-- usage after :: : retagged correctly
But I expected this output instead (and this is what PHP <= 8.2 produces):
T_STRING [NEW]
T_STRING [NEW]
https://3v4l.org/r4Yni — shows the regression starts exactly at 8.3.0 (all 8.2.x
produce the expected output; 8.3.0 through 8.5.10 produce the wrong one).
Trigger conditions
The retagging only fails when the same reserved word occurs both as the
declared constant name and as a :: constant fetch in the initializer:
| Code | Declared name token on 8.3+ |
|---|---|
class F { const NEW = 1; } |
T_STRING ✅ |
class F { const NEW = Bar::BAZ; } |
T_STRING ✅ |
class F { const FOO = Bar::NEW; } |
(usage) T_STRING ✅ |
class F { const NEW = Bar::NEW; } |
T_NEW ❌ |
class F { const NEW = [self::NEW]; } |
T_NEW ❌ |
Reproduced with other semi-reserved keywords as well (the issue is not specific
to new).
Suspected cause
ext/tokenizer/tokenizer.c handles the parser feedback for
"keyword used as identifier" by searching the already-collected token list
backwards by token text and retagging the first match:
case ON_FEEDBACK: {
HashTable *tokens_ht = ctx->tokens;
zval *token_zv, *id_zv = NULL;
ZEND_HASH_REVERSE_FOREACH_VAL(tokens_ht, token_zv) {
id_zv = extract_token_id_to_replace(token_zv, text, length);
if (id_zv) {
break;
}
} ZEND_HASH_FOREACH_END();
...
Up to PHP 8.2 the class-constant name was reduced (and the feedback emitted)
before the initializer was scanned, so the reverse-by-text search found the
correct token. With typed class constants (PHP 8.3, #10444) the grammar has
to disambiguate the type from the constant name, the reduction of the name
happens later, and by the time the feedback fires the initializer tokens have
already been scanned — so the reverse search finds the initializer occurrence
of the same text instead of the declaration, leaving the declared name tagged
as a keyword.
PHP Version
- PHP 8.2.33 — not affected (expected output)
- PHP 8.3 (
php:8.3-cli) — affected - PHP 8.4 (
php:8.4-cli) — affected - PHP 8.5.10 (
php:8.5-cli) — affected
Operating System
Reproduced on Debian-based official Docker images — the behaviour is platform
independent.
PHP Version
PHP 8.5.9 (cli) (built: Jul 28 2026 13:06:52) (NTS)
Copyright (c) The PHP Group
Built by Homebrew
Zend Engine v4.5.9, Copyright (c) Zend Technologies
with Zend OPcache v8.5.9, Copyright (c), by Zend Technologies
Operating System
No response
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Come iniziare
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Direzione di ricerca
Inizia da ext/tokenizer/tokenizer.c, in particolare dalla gestione di ON_FEEDBACK e dal percorso extract_token_id_to_replace(), quindi riproduci l’esempio token_get_all($code, TOKEN_PARSE) dell’issue. Confronta la sequenza dei token per class Foo { public const NEW = Bar::NEW; } tra PHP 8.2 e PHP 8.3+. Il lavoro è completato quando sia l’occorrenza nella dichiarazione sia quella nell’inizializzatore producono T_STRING, senza introdurre regressioni negli altri casi attivatori.
Scritto dal modello di indicizzazione a partire dal testo della issue.
Valutazione
- Stack tecnologico
- c, php
- Ambito
- compilers
- Tipo di issue
- Bug
- Difficoltà
- 4/5
- Tempo stimato
- 3-5 giorni
- Stato di attività
- Attiva
- Chiarezza
- Specificata chiaramente
- Idoneità per principianti
- 55/100