rfc:catchable-call-to-member-of-non-object

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rfc:catchable-call-to-member-of-non-object [2014/04/28 01:02] – thekidrfc:catchable-call-to-member-of-non-object [2017/09/22 13:28] (current) – external edit 127.0.0.1
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 ====== PHP RFC: Catchable "call to a member function of a non-object" ====== ====== PHP RFC: Catchable "call to a member function of a non-object" ======
-  * Version: 1.0+  * Version: 1.1
   * Date: 2014-04-26   * Date: 2014-04-26
   * Author: Timm Friebe <thekid@php.net>   * Author: Timm Friebe <thekid@php.net>
-  * Status: Under Discussion+  * Status: Accepted
   * First Published at: https://wiki.php.net/rfc/catchable-call-to-member-of-non-object   * First Published at: https://wiki.php.net/rfc/catchable-call-to-member-of-non-object
 +
 +**Note: This RFC has been superseded by the [[https://wiki.php.net/rfc/engine_exceptions_for_php7|engine exceptions]] proposal.**
  
 ===== Introduction ===== ===== Introduction =====
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 ==== Differences from Past RFCs ==== ==== Differences from Past RFCs ====
 This proposal doesn't go as far as the controversial RFC [[engine_exceptions|RFC: Engine exceptions]]. This proposal doesn't go as far as the controversial RFC [[engine_exceptions|RFC: Engine exceptions]].
 +
 +==== Inner workings ==== 
 +
 +Taken this code:
 +
 +<PHP>
 +function a($comparator) {
 +  $result= $comparator->compare(1, 2);
 +  // ...
 +}
 +</PHP>
 +
 +You can unwind this to something like:
 +
 +  function a($comparator) {
 +    1: ZEND_INIT_METHOD_CALL $comparator 'compare'
 +    2: ZEND_SEND_VAL         1
 +    3: ZEND_SEND_VAL         2
 +    4: ZEND_DO_FCALL_BY_NAME
 +    5: ZEND_ASSIGN           $result
 +    // ...
 +  }
 +
 +The handling on checking whether the method is callable happends inside
 +the opline #1 (''ZEND_INIT_METHOD_CALL''). The opcode handler for it 
 +checks its first argument (here: ''$comparator'') whether it is an object
 +or not. In case it's not, the following happens:
 +
 +  - A recoverable error is triggered. Should the script exit here, there's nothing more to be done, this is just as it was before.
 +  - In case the script continues, all the oplines are skipped until we find the ''FCALL_BY_NAME'' opcode. This is comparable to jumping forward just as, e.g., the ''ZEND_JMP'' instruction would.
 +  - The return value is set to ''ZVAL_NULL()''.
 +  - The control is handed back to the executor, which then continues with the ''ASSIGN'' opcode
 +  - The engine is again in full control; if an exception was raised by the handler, that leads to the known behavior.
  
 ===== Other Impact ===== ===== Other Impact =====
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   * Also allowing to catch and handle other fatal errors   * Also allowing to catch and handle other fatal errors
 +
 +===== Vote =====
 +Voting started 2014-06-29 and ended 2014-07-30. 
 +
 +<doodle title="Catchable Call to a member function bar() on a non-object" auth="thekid" voteType="single" closed="true">
 +   * Yes
 +   * No
 +</doodle>
 +
  
 ===== References ===== ===== References =====
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   * HHVM [[https://github.com/facebook/hhvm/blob/master/hphp/test/quick/method-non-object.php.expectf|throws a BadMethodCallException]] in these situations    * HHVM [[https://github.com/facebook/hhvm/blob/master/hphp/test/quick/method-non-object.php.expectf|throws a BadMethodCallException]] in these situations 
   * [[http://news.php.net/php.internals/73814|Mailing list announcement]]   * [[http://news.php.net/php.internals/73814|Mailing list announcement]]
 +  * [[rfc/returntypehinting|Return type hinting RFC]] - related work: Some fatal errors can be prevented by setting return types.
rfc/catchable-call-to-member-of-non-object.1398646973.txt.gz · Last modified: 2017/09/22 13:28 (external edit)

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