symfony/symfony — pull request #8688 by ShiraNai7 (2013-08-07 13:56:46+00:00)
Title: [Debug] Make sure ContextErrorException is loaded during compile time errors

| Q | A
| ------------- | ---
| Bug fix? | yes
| New feature? | no
| BC breaks? | no
| Deprecations? | no
| Tests pass? | no
| Fixed tickets | n/a
| License | MIT
| Doc PR | n/a

### Description

When the `ErrorHandler->handle()` attempts to throw a `ContextErrorException` the script might die with a Fatal Error because the class is not found.

FatalErrorException: Error: Class 'Symfony\Component\Debug\Exception\ContextErrorException' not found in ...

That effectively hides the original error and causes confusion.

### Cause

The cause is a bug/limitation of PHP that makes class autoloading completely inactive during "compiling".

Relevant PHP source code in `zend_execute_API.c`:

/* The compiler is not-reentrant. Make sure we __autoload() only during run-time
* (doesn't impact functionality of __autoload()
*/
if (!use_autoload || zend_is_compiling(TSRMLS_C)) {

#### More information about the PHP bug/limitation:
- https://bugs.php.net/bug.php?id=65322
- many duplicates/relevant: https://www.google.com/search?btnG=1&pws=0&q=site%3Abugs.php.net+autoload+error+handling

### The fix

The most simple way to fix this is to manually ensure that `ContextErrorException` is loaded and if not, load it. This is what I did.

Another way is to detect if autoloading is available (possible by prepending a temporary autoloader) and act accordingly (how?).

### The test

I also added a test case that would fail with a fatal error if the error handler does not successfully throw an exception in case of a compile time error. But I'm not sure if this is the best way or if there should be a test case at all.

###