Description:
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When using array_fetch with an array of keys, if one of the keys is the string representation of a number then that key cannot be accessed in the returned array due to PHP's auto conversion of array keys that are string based representations of numbers to numbers. Reproduction of this issue does not require Apache or any other special configuration of PHP other then the installation and enabling of the APC extension.

Reproduce code:
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<?php
apc_store ("123", "value1");
apc_store ("test", "value2");

$results = apc_fetch (array ("123","test"));

var_dump (isset($results["123"]));

Expected result:
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That "bool(true)" is returned by the var_dump and that the element is accessible in the array via all array access methods supported by PHP.

Actual result:
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The actual result is that "bool(false)" is returned by the var_dump and this element in the array cannot be accessed via the array subscript method.