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6173a9a109
The aim of this PR is twofold:
- Reduce the number of highly similar TMP|VAR handlers
- Avoid ZVAL_DEREF in most of these cases
This is achieved by guaranteeing that all zend_compile_expr() calls, as well as
all other compile calls with BP_VAR_{R,IS}, will result in a TMP variable. This
implies that the result will not contain an IS_INDIRECT or IS_REFERENCE value,
which was mostly already the case, with two exceptions:
- Calls to return-by-reference functions. Because return-by-reference functions
are quite rare, this is solved by delegating the DEREF to the RETURN_BY_REF
handler, which will examine the stack to check whether the caller expects a
VAR or TMP to understand whether the DEREF is needed. Internal functions will
also need to adjust by calling the zend_return_unwrap_ref() function.
- By-reference assignments, including both $a = &$b, as well as $a = [&$b]. When
the result of these expressions is used in a BP_VAR_R context, the reference
is unwrapped via a ZEND_QM_ASSIGN opcode beforehand. This is exceptionally
rare.
Closes GH-20628
35 lines
769 B
PHP
35 lines
769 B
PHP
--TEST--
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GH-20836 (Stack overflow in mb_convert_variables with recursive array references)
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--EXTENSIONS--
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mbstring
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--FILE--
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<?php
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$a = [];
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$b = [];
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$b[] = &$a;
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$a[] = &$b;
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var_dump(mb_convert_variables('utf-8', 'utf-8', $a));
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$c = [];
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$c[] = &$c;
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var_dump(mb_convert_variables('utf-8', 'utf-8', $c));
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$normal = ['test', 'array'];
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var_dump(mb_convert_variables('utf-8', 'utf-8', $normal));
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$d = ['level1' => ['level2' => ['level3' => 'data']]];
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var_dump(mb_convert_variables('utf-8', 'utf-8', $d));
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echo "Done\n";
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?>
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--EXPECTF--
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Warning: mb_convert_variables(): Cannot handle recursive references in %s on line %d
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bool(false)
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Warning: mb_convert_variables(): Cannot handle recursive references in %s on line %d
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bool(false)
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string(5) "UTF-8"
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string(5) "UTF-8"
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Done
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