PHP RFC: Catching Multiple Exception Types
- Version: 1.0
- Date: 2016-03-06
- Author: Pierrick Charron pierrick@php.net, Bronisław Białek after89@gmail.com
- Status: Implemented (PHP 7.1)
- First Published at: https://wiki.php.net/rfc/multiple-catch
Introduction
When two different types of exceptions are handled the same way, it is sometimes required to duplicate the code of the catch statements.
For example :
<?php try { // Some code... } catch (ExceptionType1 $e) { // Code to handle the exception } catch (ExceptionType2 $e) { // Same code to handle the exception } catch (Exception $e) { // ... }
A solution to fix this problem on the user level would be to implement a common interface for ExceptionType1 and ExceptionType2 and catch it. However, this is only possible when you control the exception hierarchy in your own code, but not possible when you don't control the code.
Proposal
This RFC introduces the possibility to catch multiple exception types in a single catch statement to avoid code duplication.
<?php try { // Some code... } catch (ExceptionType1 | ExceptionType2 $e) { // Code to handle the exception } catch (\Exception $e) { // ... }
This syntax and functionality is compatible with the Union types RFC proposed here : https://wiki.php.net/rfc/union_types
When is it useful ?
- When a single method/function throw two different types of exceptions that you handle the same way;
- When libraries are leaking their dependency's exceptions.
Backward Incompatible Changes
None.
Proposed PHP Version(s)
7.1
RFC Impact
To SAPIs
None
To Existing Extensions
None
To Opcache
None
To PHP tools/IDE
This change will require every PHP tools and IDE based on an AST parser to be modified to take this syntax change into account.
Links and Literature
Similar feature in Java: https://docs.oracle.com/javase/7/docs/technotes/guides/language/catch-multiple.html
Request on StackOverflow: https://stackoverflow.com/questions/8439581/catching-multiple-exception-types-in-one-catch-block
Vote
As this is a language change, a 2/3 majority is required. The vote is a straight Yes/No vote for accepting the RFC and merging the patch. Voting started on 2016-04-17 and will end on 2016-05-01.
Patches and Tests
Implementation
Merged into php-src for PHP 7.1: https://github.com/php/php-src/commit/0aed2cc2a440e7be17552cc669d71fdd24d1204a