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random: Do not use ZVAL_DUP in Randomizer::shuffleArray() #16072

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Sep 28, 2024
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random: Do not use ZVAL_DUP in Randomizer::shuffleArray() #16072

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random: Do not use ZVAL_DUP in Randomizer::shuffleArray() 
PHP Internals Book says:

> The ZVAL_DUP macro is similar to ZVAL_COPY, but will duplicate arrays, rather
> than just incrementing their refcount. If you are using this macro, you are
> almost certainly doing something very wrong.

Replace this by an explicit call to `zend_array_dup()`, as done in
`php_array_diff()`. Besides being more explicit in what is happening, this
likely also results in better assembly.
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@TimWolla
TimWolla committed Sep 26, 2024
commit 1b9c6324ccd2fb3ee303f2add7fba1036a92dc46
2 changes: 1 addition & 1 deletion ext/random/randomizer.c
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Expand Up @@ -356,7 +356,7 @@ PHP_METHOD(Random_Randomizer, shuffleArray)
Z_PARAM_ARRAY(array)
ZEND_PARSE_PARAMETERS_END();

ZVAL_DUP(return_value, array);
RETVAL_ARR(zend_array_dup(Z_ARRVAL_P(array)));
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Is there a particular reason for not using SEPARATE_ARRAY()? This would avoid a duplication when it's not stricly necessary, e.g.:

$r->shuffleArray(range(0,10));

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Do you have a specific suggestion as how to adjust the code to leverage SEPARATE_ARRAY? My attempts all lead to either memory unsafety or SEPARATE_ARRAY not providing a value-add.

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You are right indeed, there SEPARATE_ARRAY would not make sense here.

if (!php_array_data_shuffle(randomizer->engine, return_value)) {
RETURN_THROWS();
}
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