Running the installer on your existing wiki can fail when extension entry points expect their own classes to be registered already when we call Installer::getExistingLocalSettings(). Since the require() there isn't in the global scope, $wgAutoloadClasses doesn't "work" and the subsequent call to the class will fail.
Fatal error: Class 'MwEmbedResourceManager' not found in /vagrant/mediawiki/extensions/MwEmbedSupport/MwEmbedSupport.php on line 58
Call Stack:
0.0000 638800 1. {main}() /vagrant/mediawiki/mw-config/index.php:0
0.0281 3246320 2. wfInstallerMain() /vagrant/mediawiki/mw-config/index.php:31
0.0852 7279256 3. WebInstaller->execute() /vagrant/mediawiki/mw-config/index.php:72
0.0903 7662024 4. WebInstallerExistingWiki->execute() /vagrant/mediawiki/includes/installer/WebInstaller.php:280
0.0903 7662024 5. Installer::getExistingLocalSettings() /vagrant/mediawiki/includes/installer/WebInstallerPage.php:316
0.0908 8019208 6. require('/vagrant/mediawiki/LocalSettings.php') /vagrant/mediawiki/includes/installer/Installer.php:541
0.0915 8020256 7. require_once('/vagrant/LocalSettings.php') /vagrant/mediawiki/LocalSettings.php:128
0.0929 8028128 8. include_once('/vagrant/settings.d/puppet-managed/10-CirrusSearch.php') /vagrant/LocalSettings.php:91
0.0935 8087728 9. include_once('/vagrant/mediawiki/extensions/CirrusSearch/tests/jenkins/Jenkins.php') /vagrant/settings.d/puppet-managed/10-CirrusSearch.php:6
0.0943 8149968 10. require_once('/vagrant/mediawiki/extensions/MwEmbedSupport/MwEmbedSupport.php') /vagrant/mediawiki/extensions/CirrusSearch/tests/jenkins/Jenkins.php:45This is based on me running Cirrus + MwEmbedSupport on vagrant but it's not specific to any of these cases. You could do a simpler case like this in your LocalSettings:
// other config above here
require_once( "test.php" );
With a test.php of:
<?php
$wgAutoloadClasses['foo'] = 'foo.php';
foo::bar()
This coding style works when in normal execution but explodes for very obvious reasons otherwise. Other than "we shouldn't do that and fix instances where we are" can we think of any sorts of ways to mitigate the problem?
Version: unspecified
Severity: normal