[RFC] Convert exit (and die) from language constructs to functions #13483
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Zend/zend_execute.c
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| if (UNEXPECTED( | ||
| zend_string_equals_literal_ci(Z_STR_P(key), "exit") | ||
| || zend_string_equals_literal_ci(Z_STR_P(key), "die") | ||
| )) { | ||
| zend_throw_unwind_exit(); | ||
| return FAILURE; | ||
| } |
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Could we achieve similar results with by de-sugaring exit; to a function call at the AST level? (e.g. zend_compile_const() can replace the AST with a function call AST and delegate to zend_compile_call()). This would remove the need for special cases at runtime, and also unify the behavior of exit; and exit(); (wrt to disable_functions).
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I agree. Special-casing exit/die constant access doesn't sound like a cleaner solution than what we have now. Keeping them in the lexer/parser also keeps BC for AST-based tools.
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Yes, and it has side effects like defined(), constant() calls etc.
We may opt to special-case only statement-level "exit" and "die" constant fetches directly (i.e. handle in zend_compile_stmt, in the branch for constants).
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Oh, that's actually a smarter way of doing it!
I'll see if I can implement this, as I still struggle with the compiler part.
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We may opt to special-case only statement-level "exit" and "die" constant fetches directly (i.e. handle in zend_compile_stmt, in the branch for constants).
I would prefer keeping parser support, as otherwise PHPStan and the likes need to adjust. I don't think there's a reason to break those. Edit: I guess lexer would be sufficient, as almost all of these tools use PHPParser, which defines its own AST. Still, I'd prefer letting the parser handle this.
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I was about to suggest something similar, because exit; not actually calling the function but just throwing that unwind exception probably leads to observable behavioral differences in debuggers dependent on whether the user wrote exit; or exit();, no?
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I don't think we should constrain ourselves with respect to phpstan etc.; there are worse BC breaks to be had.
I think the lexer, parser and opcodes are aside from any compatibilty guarantees.
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@ondrejmirtes has told me that this shouldn't be an issue if PHPParser still works, I'm asking @dseguy if this would affect Exakat or not.
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@exakat will need an adaptation, at the parser level. That is not an issue.
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Where is the RFC? Removing ability to use Please consider the possibility of adding die/exit functions without removing opcodes. |
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@dstogov See zend_compile.c, the constants are turned into function calls. That said, I'm also a bit sceptical about the proposed benefits. I think an RFC, or at least a list on the mailing list explaining the rationale would be reasonable. |
The PR name contains |
Nice hack :), but it needs to be verified (constants may be used in places where calls are not allowed). |
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The RFC is now live: https://wiki.php.net/rfc/exit-as-function and I have sent an email to internals. I'm still somewhat ill so I didn't manage to post it yesterday. |
The main motivation here is to have the same type juggling semantics as every other function in PHP.
Also, we don't need to have an opcode any more for it.
RFC: https://wiki.php.net/rfc/exit-as-function