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Opened 10 years ago

Last modified 5 years ago

#20263 closed defect (bug)

Backticks in dbDelta cause warning and actually causes a query to alter all columns and indexes to run even if none have changed — at Initial Version

Reported by: Driskell Owned by:
Milestone: 4.6 Priority: normal
Severity: normal Version: 1.5
Component: Database Keywords: has-unit-tests has-patch
Focuses: Cc:

Description

Backticks in a CREATE TABLE in a dbDelta call are causing the below warning, and running a query to alter all columns and indexes with backticks even if they haven't changed:
Notice: Undefined offset: 1 in /home/backuptechnology/public_html/wp-admin/includes/upgrade.php on line 1544

Seems this started a long long time ago after this was fixed:
http://core.trac.wordpress.org/ticket/8014

Seems there is a match on line 1587 of WordPress 3.3.1 wp-admin/includes/upgrade.php:

               // For every field in the table
                foreach ($tablefields as $tablefield) {
                        // If the table field exists in the field array...
                        if (array_key_exists(strtolower($tablefield->Field), $cfields)) {
                                // Get the field type from the query
                                preg_match("|".$tablefield->Field." ([^ ]*( unsigned)?)|i", $cfields[strtolower($tablefield->Field)], $matches);

The preg_match bit is what fails to match because it is looking for "fieldname" instead of "fieldname".
So this is where the warning occurs, and why it assumes the type of the field is wrong.
This means the previous patch 3 years ago probably meant when you have backticks in your CREATE TABLE, when you run dbDelta it actually runs an ALTER TABLE for every single column in the table, and then an ALTER TABLE ADD INDEX / PRIMARY for every single KEY and PRIMARY (there's more than just the above code that needs adjusting), causing duplicate key errors, but ignored. Guess it kinda works though...

Also seems during the DESCRIBE it doesn't use backticks so if someone has a table with a reserved name (stupid I know) it would break dbDelta completely, but that's me digressing I just think getting rid of the warnings for CREATE TABLES with backticks will be good.

But explains why my plugin takes a few seconds to activate hahaha. :-)

I'll provide a patch at some point this week or next unless someone has already done so.

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