rfc:engine_exceptions

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rfc:engine_exceptions [2013/10/24 17:34] – add section about not all errors being converted nikicrfc:engine_exceptions [2017/09/22 13:28] (current) – external edit 127.0.0.1
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   * Date: 2013-10-23   * Date: 2013-10-23
   * Author: Nikita Popov <nikic@php.net>   * Author: Nikita Popov <nikic@php.net>
-  * Status: In Draft+  * Status: Declined for 5.6
   * Proposed for: PHP 5.6   * Proposed for: PHP 5.6
   * Patch: https://github.com/nikic/php-src/compare/engineExceptions   * Patch: https://github.com/nikic/php-src/compare/engineExceptions
 +  * ML discussion: http://markmail.org/message/uemuxsk3vk46nedo
  
 ===== Introduction ===== ===== Introduction =====
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 This RFC proposes to allow the use of exceptions in the engine and to allow the replacement of existing fatal or recoverable fatal errors with exceptions. This RFC proposes to allow the use of exceptions in the engine and to allow the replacement of existing fatal or recoverable fatal errors with exceptions.
  
-As an example of this change, consider the following the following code-snippet:+As an example of this change, consider the following code-snippet:
  
 <code php> <code php>
Line 123: Line 124:
  
 <code php> <code php>
-$lock->aquire();+$lock->acquire();
 try { try {
     doSomething();     doSomething();
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     public function __construct(Lock $lock) {     public function __construct(Lock $lock) {
         $this->lock = $lock;         $this->lock = $lock;
-        $this->lock->aquire();+        $this->lock->acquire();
     }     }
     public function __destruct() {     public function __destruct() {
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 function test($lock) { function test($lock) {
-    $manager = new LockManager($lock); // aquire lock+    $manager = new LockManager($lock); // acquire lock
          
     doSomething();     doSomething();
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 ==== Not all errors converted ==== ==== Not all errors converted ====
  
-PHP currently (master on 2013-10-24) contains the following number of fatal-y errors:+The Zend Engine currently (master on 2013-12-10) contains the following number of fatal-y errors:
  
 <code> <code>
-E_ERROR:            439    (note: not counting 538 occurrences in zend_vm_execute.h) +E_ERROR:            183    (note: not counting 538 occurrences in zend_vm_execute.h) 
-E_CORE_ERROR:        14 +E_CORE_ERROR:        12 
-E_COMPILE_ERROR:    145+E_COMPILE_ERROR:    151
 E_PARSE:              1 E_PARSE:              1
-E_RECOVERABLE_ERROR: 21+E_RECOVERABLE_ERROR: 14
 </code> </code>
  
-The patch attached to the RFC currently (as of 2013-10-24) removes 70 ''E_ERROR''s and 11 ''E_RECOVERABLE_ERROR''s. While I hope to port more errors to exceptions before the patch is merged, the process is rather time consuming and I will not be able to convert all errors or even most of them. (Note: The number of occurrences in the source code says rather little about what percentage of "actually thrown" errors this constitutes.)+The count was obtained using ''git grep "error[^(]*(E_ERROR_TYPE" Zend | wc -l'' and as such may not be totally accurate, but should be a good approximation.
  
-Some errors are easy to change to exceptions, others are more complicated. Some are nigh impossible, like the memory limit or execution time limit errors. The ''E_CORE_ERROR'' type can't be converted to use exceptions because it occurs during startup (at least if used correctly). ''E_COMPILE_ERROR'' (and ''E_PARSE'') currently also can't be converted to exceptions, due to concerns regarding global state modifications.+The patch attached to the RFC currently (as of 2013-10-24) removes 70 ''E_ERROR''s and 11 ''E_RECOVERABLE_ERROR''s. While I hope to port more errors to exceptions before the patch is merged, the process is rather time consuming and I will not be able to convert all errors. (Note: The number of occurrences in the source code says rather little about what percentage of "actually thrown" errors this constitutes.) 
 + 
 +Some errors are easy to change to exceptions, others are more complicated. Some are impossible, like the memory limit or execution time limit errors. The ''E_CORE_ERROR'' type can't be converted to use exceptions because it occurs during startup (at least if used correctly). ''E_COMPILE_ERROR'' (and ''E_PARSE'') currently also can't be converted to exceptions, due to concerns regarding global state modifications.
  
 Converting most existing errors will take some time and in the meantime we'll be in a situation where some part of the errors were converted to exceptions but another part stays fatal. From a user perspective it may not be immediately clear when one is used over the other. Converting most existing errors will take some time and in the meantime we'll be in a situation where some part of the errors were converted to exceptions but another part stays fatal. From a user perspective it may not be immediately clear when one is used over the other.
  
 While this may be slightly inconvenient, I strongly think that it's better to start fixing this gradually, rather than waiting until the time (that will never come) where we can fix everything at once. While this may be slightly inconvenient, I strongly think that it's better to start fixing this gradually, rather than waiting until the time (that will never come) where we can fix everything at once.
 +
 +===== Backwards compatibility =====
 +
 +The ''E_ERROR'' portion of this proposal does not break backwards compatibility: All code that was previously working, will continue to work. The change only relaxes error conditions, which is generally not regarded as breaking BC.
 +
 +The ''E_RECOVERABLE_ERROR'' part of the proposal may introduce a minor BC break, because it will no longer allow to silently ignore recoverable errors with a custom error handler. As this point is somewhat controversial I'll have a separate voting option for this.
  
 ===== Patch ===== ===== Patch =====
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 The patch introduces basic infrastructure for this change and removes all ''E_ERROR'' uses from ''zend_vm_def.h'' (as well as some other errors). The patch introduces basic infrastructure for this change and removes all ''E_ERROR'' uses from ''zend_vm_def.h'' (as well as some other errors).
 +
 +===== Vote =====
 +
 +This is a yes/no vote with the additional option of implementing the proposal, but without changing ''E_RECOVERABLE_ERROR''s (as that part of the proposal may have BC issues).
 +
 +As this is a language-related change, the vote requires a two-third majority. The 3-way vote will be interpreted as follows: If 2/3 of the total votes are for "Yes", the proposal is implemented fully. If 2/3 of the votes are for "Yes" or "Yes, without E_RECOVERABLE_ERROR changes" then the proposal is implemented without the ''E_RECOVERABLE_ERROR'' changes. Otherwise, the proposal is not implemented.
 +
 +If you are in favor of this proposal in general, but not for PHP 5.6, use the "No" voting option.
 +
 +<doodle title="Implement in PHP 5.6?" auth="nikic" voteType="single" closed="true">
 +   * Yes
 +   * Yes, without E_RECOVERABLE_ERROR changes
 +   * No
 +</doodle>
 +
 +Vote started on 2013-12-07 and ended on 2013-12-14.
rfc/engine_exceptions.1382636050.txt.gz · Last modified: 2017/09/22 13:28 (external edit)

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