rfc:convert_numeric_keys_in_object_array_casts

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rfc:convert_numeric_keys_in_object_array_casts [2017/09/22 13:28]
127.0.0.1 external edit
rfc:convert_numeric_keys_in_object_array_casts [2017/11/30 14:50] (current)
ajf
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 Various edge cases in the Zend Engine exist where array HashTables can contain numeric string keys, and object HashTables can contain integer keys. In such cases, these keys are inaccessible from PHP code, because the code handling arrays will never look for numeric string keys in the HashTable (as arrays map those to integer keys), and the code handling objects will never look for integer keys in the HashTable (as objects map those to string keys). Various edge cases in the Zend Engine exist where array HashTables can contain numeric string keys, and object HashTables can contain integer keys. In such cases, these keys are inaccessible from PHP code, because the code handling arrays will never look for numeric string keys in the HashTable (as arrays map those to integer keys), and the code handling objects will never look for integer keys in the HashTable (as objects map those to string keys).
  
-This RFC focuses on a specific edge case, that of object-to-array casts and array-to-object casts. Currently, when using <php>(object)</php> or <php>settype()</php> to convert an object to an array, or when using <php>(array)</php> or <php>settype()</php> to convert an array to an object, the inner HashTable is naïvely copied or referenced without its keys being changed to reflect the restrictions on array keys and object property names, leading to inaccessible array keys or object properties in some cases. For example, <php>$arr = [0 => 1, 1 => 2, 2 => 3]; $obj = (object)$arr;</php> produces an object with inaccessible properties named <php>0</php>, <php>1</php> and <php>2</php>, while <php>$obj = new stdClass; $obj->{'0'} = 1; $obj->{'1'} = 2; $obj->{'2'} = 3;</php> produces an array with the inaccessible keys <php>"0"</php>, <php>"1"</php> and <php>"2"</php>. The same issue also occurs when using <php>get_object_vars()</php>.+This RFC focuses on a specific edge case, that of object-to-array casts and array-to-object casts. Currently, when using <php>(object)</php> or <php>settype()</php> to convert an object to an array, or when using <php>(array)</php> or <php>settype()</php> to convert an array to an object, the inner HashTable is naïvely copied or referenced without its keys being changed to reflect the restrictions on array keys and object property names, leading to inaccessible array keys or object properties in some cases. For example, <php>$arr = [0 => 1, 1 => 2, 2 => 3]; $obj = (object)$arr;</php> produces an object with inaccessible properties named <php> 0</php>, <php>1</php> and <php>2</php>, while <php>$obj = new stdClass; $obj->{'0'} = 1; $obj->{'1'} = 2; $obj->{'2'} = 3; $arr = (array)$obj;</php> produces an array with the inaccessible keys <php>"0"</php>, <php>"1"</php> and <php>"2"</php>. The same issue also occurs when using <php>get_object_vars()</php>.
  
 ===== Proposal ===== ===== Proposal =====
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 ==== High-level ==== ==== High-level ====
  
-This RFC proposes to fix this issue for object-to-array casts and array-to-object casts, both for the casting operators and for <php>settype()</php>, and also fix the same issue in <php>get_object_vars()</php>. This would be done by converting the keys of array or object HashTables as appropriate, so numeric string property names in objects would be converted to integer array keys, and vice-versa. Therefore, there would be no inaccessible properties. For example, <php>$arr = [0 => 1, 1 => 2, 2 => 3]; $obj = (object)$arr;</php> would now produce an object with accessible properties named <php>"0"</php>, <php>"1"</php> and <php>"2"</php>, and <php>$obj = new stdClass; $obj->{'0'} = 1; $obj->{'1'} = 2; $obj->{'2'} = 3;</php> would now produce an array with the accessible keys <php>0</php>, <php>1</php> and <php>2</php>.+This RFC proposes to fix this issue for object-to-array casts and array-to-object casts, both for the casting operators and for <php>settype()</php>, and also fix the same issue in <php>get_object_vars()</php>. This would be done by converting the keys of array or object HashTables as appropriate, so numeric string property names in objects would be converted to integer array keys, and vice-versa. Therefore, there would be no inaccessible properties. For example, <php>$arr = [0 => 1, 1 => 2, 2 => 3]; $obj = (object)$arr;</php> would now produce an object with accessible properties named <php>"0"</php>, <php>"1"</php> and <php>"2"</php>, and <php>$obj = new stdClass; $obj->{'0'} = 1; $obj->{'1'} = 2; $obj->{'2'} = 3; $arr = (array)$obj;</php> would now produce an array with the accessible keys <php> 0</php>, <php>1</php> and <php>2</php>.
  
 ==== Internals ==== ==== Internals ====
rfc/convert_numeric_keys_in_object_array_casts.1506086901.txt.gz · Last modified: 2017/09/22 13:28 by 127.0.0.1