Last modified: 2010-05-15 15:38:26 UTC
Setup: Debian Woody r3.0 (a.k.a. "Brion's mortal enemy") running PHP 4.1.2 with MediaWiki 1.5.0 Background: Trying to modify MediaWiki to make it suitable for use for running my personal homepage. To repo: 0) To LocalSettings.php add "$wgUseDatabaseMessages = false;", so as to allow the UI to be customized. 1) Edit languages/LanguageEn.php, and add this line: $wgAllMessagesEn['mainpage'] = "Nick's Homepage"; 2) Login as Wikisysop. 3) Move the "Main Page", to "Nick's Homepage". Expected results: The move succeeds. Actual Results: Gives this error: -------------------------- Warning: Wrong datatype for first argument in call to array_key_exists in /var/www/hosts/wiki-homepage/wiki/includes/Hooks.php on line 42 Fatal error: Call to a member function on a non-object in /var/www/hosts/wiki-homepage/wiki/includes/Title.php on line 664 -------------------------- Should this work, or have I done something dumb? Also despite the error it seems to have moved the page successfully, so setting the severity to "minor".
If the page moved, then I wouldn't worry. However, you don't need to make changes to the code to change the interface any more. Going into MediaWiki:Mainpage and changing the text there to "Nick's Homepage" would have set up the default page easily; moving the page from "Main Page" to "Nick's Homepage" is a trifling matter. Then again, you seem to be more worried about the error message, and rightly so. Can you reproduce the error - does moving any other page throw up the same results?
Thank you for the tip about "MediaWiki:Mainpage" - that's a much easier way of doing it. With the error, I can reproduce the error on the current wiki. Created an article called "Test", and then moved it to "Test's test". Gives this error: -------------------- Warning: Wrong datatype for first argument in call to array_key_exists in /var/www/hosts/wiki-homepage/wiki/includes/Hooks.php on line 42 Fatal error: Call to a member function on a non-object in /var/www/hosts/wiki-homepage/wiki/includes/Title.php on line 664 -------------------- So as to eliminate any changes or customizations that I may have made being the cause of the problem, I made a new virtual host, with an unmodified copy of MediaWiki 1.5.0, and recorded all the steps I followed starting right at installation through to getting the error message. Steps are shown below in the hope that it may be of assistance: ludo:/var/www/# cd /var/www/hosts/ ludo:/var/www/hosts# mkdir mediawiki-test ludo:/var/www/hosts# cd mediawiki-test ludo:/var/www/hosts/mediawiki-test# tar xfz ~/tmp/mediawiki-1.5.0.tar.gz ludo:/var/www/hosts/mediawiki-test# mv mediawiki-1.5.0/ wiki ludo:/var/www/hosts/mediawiki-test# chown -R www-data.www-data /var/www/hosts ludo:/var/www/hosts/mediawiki-test# Then the browser steps: * open http://mediawiki-test/wiki * click setup link * gives this output: Please include all of the lines below when reporting installation problems. Checking environment... * WARNING: PHP 4.3.2 or higher is recommended. Older versions from 4.1.x up may work but are not actively supported. PHP 4.1.2: ok * Warning: PHP's register_globals option is enabled. MediaWiki will work correctly, but this setting increases your exposure to potential security vulnerabilities in PHP-based software running on your server. You should disable it if you are able. * PHP server API is apache; ok, using pretty URLs (index.php/Page_Title) * Have XML / Latin1-UTF-8 conversion support. * PHP's memory_limit is 16M. If this is too low, installation may fail! Attempting to raise limit to 20M... ok. * Have zlib support; enabling output compression. * Neither Turck MMCache nor eAccelerator are installed, can't use object caching functions * GNU diff3 not found. * Found GD graphics library built-in, image thumbnailing will be enabled if you enable uploads. * Installation directory: /var/www/hosts/mediawiki-test/wiki * Script URI path: /wiki * Configure as follows: Site name: mediawiki-test Contact e-mail: <I'm omitting this to limit spam> Language: en- English no license metadata Sysop account name: Nickj password: test pwd again: test no caching email: enabled User-to-user e-mail: enabled E-mail notification: enabled for changes of watch-listed and user_talk pages E-mail address authentication: disabled MySQL server: localhost Database name: wikitest db user: wikiuser DB password: test DB wd again: test Database table prefix: <blank/none/not specified> DB root password: <blank/none/not specified> * click "Install" * Output as follows: MediaWiki 1.5.0 installation Please include all of the lines below when reporting installation problems. Checking environment... * WARNING: PHP 4.3.2 or higher is recommended. Older versions from 4.1.x up may work but are not actively supported. PHP 4.1.2: ok * Warning: PHP's register_globals option is enabled. MediaWiki will work correctly, but this setting increases your exposure to potential security vulnerabilities in PHP-based software running on your server. You should disable it if you are able. * PHP server API is apache; ok, using pretty URLs (index.php/Page_Title) * Have XML / Latin1-UTF-8 conversion support. * PHP's memory_limit is 16M. If this is too low, installation may fail! Attempting to raise limit to 20M... ok. * Have zlib support; enabling output compression. * Neither Turck MMCache nor eAccelerator are installed, can't use object caching functions * GNU diff3 not found. * Found GD graphics library built-in, image thumbnailing will be enabled if you enable uploads. * Installation directory: /var/www/hosts/mediawiki-test/wiki * Script URI path: /wiki * PHP is linked with old MySQL client libraries. If you are using a MySQL 4.1 server and have problems connecting to the database, see http://dev.mysql.com/doc/mysql/en/old-client.html for help. * Trying to connect to MySQL on localhost as root... o Connected as root (automatic) * Connected to 3.23.49 * Created database wikitest * Creating tables... done. * Initializing data... * Granting user permissions... * Created sysop account Nickj. * Initialising "MediaWiki" namespace... Clearing message cache...Done. Creating LocalSettings.php... Installation successful! Move the config/LocalSettings.php file into the parent directory, then follow this link to your wiki. * Moved config/LocalSettings.php: ludo:/var/www/hosts/mediawiki-test# mv wiki/config/LocalSettings.php wiki/ ludo:/var/www/hosts/mediawiki-test# * Click the link ( http://mediawiki-test/wiki/index.php ) to open the wiki * Looks normal. * Go to http://mediawiki-test/wiki/index.php/test * Click "edit" * Type "this is a test" * save page * Click "create an account or login" (as anons cannot move page) * Enter username "Nickj", pwd "test", tick "Remember me", click "login". * Click "return the test" link * click move * Enter new title as "Test's test", click "Move page". * get a white screen with this error message: -------------------------------- Warning: Wrong datatype for first argument in call to array_key_exists in /var/www/hosts/mediawiki-test/wiki/includes/Hooks.php on line 42 Fatal error: Call to a member function on a non-object in /var/www/hosts/mediawiki-test/wiki/includes/Title.php on line 664 -------------------------------- * Then if I press the browser's back button (to go to http://wiki-homepage/wiki/index.php/Test ) I get this error message: -------------------------------- Fatal error: Call to a member function on a non-object in /var/www/hosts/wiki-homepage/wiki/includes/Database.php on line 1667 -------------------------------- * Then I went to the homepage, http://wiki-homepage/wiki/ , and it keeps giving the error above: -------------------------------- Fatal error: Call to a member function on a non-object in /var/www/hosts/wiki-homepage/wiki/includes/Database.php on line 1667 -------------------------------- * Pressing reload, and shift-reload, gives the same error. In MS Internet Explorer 5 I tried to clear the cache by going tools -> internet options -> general tab -> delete files -> ticked box to also delete offline content (just in case) -> click OK -> click OK. Then closed IE, and then restarted it (just to be safe again), and then went to http://wiki-homepage/wiki/ again. Same error message: "Fatal error: Call to a member function on a non-object in /var/www/hosts/wiki-homepage/wiki/includes/Database.php on line 1667". At this point, I think I've basically hosed my mediawiki-test wiki ... So, in answer to your question, yes, the error worries me a bit :-) Also I'm thinking now the severity might be higher than minor. -- All the best, Nick.
Please disregard from "Then if I press the browser's back button" onwards in the above message (before this about the move-error is still correct, but after this point about the database-error it is wrong). The reason is (and I should have seen this in the URLs) is that for some reason pressing back in IE went back to the original (non-test) wiki. When the test wiki was installed, I used the same DB username but a different password for the new wiki, and the setup configures the DB user's password as specified. So, the setup of the new wiki meant the original wiki could not access the database, which caused it to give an error. Strangely, it gives different messages in IE and Firefox - Firefox says: ------------------------------------------------------------------- Sorry! The wiki is experiencing some technical difficulties, and cannot contact the database server. Access denied for user: 'wikiuser@localhost' (Using password: YES) (localhost) ------------------------------------------------------------------- (which is a far more informative error) whilst IE keeps showing : ------------------------------------------------------------------- Fatal error: Call to a member function on a non-object in /var/www/hosts/wiki-homepage/wiki/includes/Database.php on line 1667 ------------------------------------------------------------------- However after changing both wikis to use the same password, then both sites can be accessed in both browsers.
Can you reproduce this with PHP 4.3.x/4.4.0/5.x?
Don't know, and I don't currently have a PHP 4.3.x/4.4.0/5.x install with which I can test this. I've also since tried moving pages without any apostrophes or any spaces in the name in case that was the problem (for example I tried moving "T2" to "T3"), and this generates the error too. On further investigation, it looks like it's this PHP bug: http://bugs.php.net/bug.php?id=20865 [array_key_exists() fails to find NULL key]. When I run the test script from that bug in PHP 4.1.2, it generates an error which says: ============================================= ludo:~# ~/tmp/test.php <br /> <b>Warning</b>: Wrong datatype for first argument in call to array_key_exists in <b>/root/tmp/test.php</b> on line <b>16</b><br /> ludo:~# ============================================= Looks pretty similar. I then edited Hooks.php as follows: ===================================================================== --- includes/Hooks.php.bak Tue Oct 11 17:15:11 2005 +++ includes/Hooks.php Tue Oct 11 17:21:56 2005 @@ -39,6 +39,11 @@ return false; } + if (is_null($event)) { + //#### wfDieDebugBacktrace("Event was null!\n"); + return false; + } + if (!array_key_exists($event, $wgHooks)) { return true; } ===================================================================== This stopped the first of the messages I see, so that now the only error message is like this: ===================================================================== Fatal error: Call to a member function on a non-object in /var/www/hosts/mediawiki-test/wiki/includes/Title.php on line 664 ===================================================================== By the way, the wfDieDebugBacktrace call is commented out because if it's not, I get this error: ===================================================================== Fatal error: Call to undefined function: wfdiedebugbacktrace() in /var/www/hosts/mediawiki-test/wiki/includes/Hooks.php on line 44 ===================================================================== ... which suggests to me that it's fairly likely that none of the other calls to wfDieDebugBacktrace (located both above and below the one I inserted) are going to work either.
Created attachment 986 [details] includes/Title.php patch for MediaWiki 1.5.0 Visual inspection of the code lead me to suspect that includes/Title.php was the problem, and specifically that it might be something to do with reference abuse (which in PHP < 4.4 can corrupt memory), plus one or more null values being used somewhere. So, I modified includes/Title.php to remove the cruft that stood out the most (namely: unused vars + one un-initialized var that should be global + unused globals + the use of references that seemed worst). Patch against MediaWiki 1.5.0 is attached. With this applied, page moves are now working successfully again in PHP 4.1.2.
Hi, If the above patch is going to take a while to review, can I please request that a one-line subset of the above patch be applied? Namely the line adding the "global $wgUser;" around line 1659. This type of fix would qualify for inclusion in a Linux 2.6.x.y point release (i.e. it's a trivial and simple and short fix, it helps fix a definite problem, which has affected real users), and for these reasons I think it would be good to apply this to MediaWiki sooner rather than later. I have not tested whether this line alone will fix page moves in PHP 4.1.2, but it is definitely a significant part of the problem.
Added the global, not touching the other bits if there's not any clear reason for it. PHP 4.1.2 is no longer supported, so don't really care if it works or not, but it's incorrect to be missing the global. :)
