The update checker uses class_exists in several ways:
- As a guard clause around `class Whatever` definitions. This ensures we don't try to define a class that has already been loaded by a different plugin. In this case, autoloading is not necessary because we already know how to load the class. Also, we *want to* load our version of that class if possible - the version that gets loaded by somebody else's autoloader might be different and incompatible.
- As a guard clause before `require` statements that include a class. This is conceptually the same as the previous example.
- To enable optional features if Debug Bar is active. The latest compatible version of Debug Bar doesn't use autoloading, so it would again be unnecessary in this case.
By convention, there should be a space before and after a string concatenation operator.
Also, both submit buttons should use a dash to separate the static and variable parts of the element ID.
This feature is disabled by default. Turn it on by setting `$checker->throttleRedundantChecks` to `true` and use `$checker->throttledCheckPeriod` to set the alternate check period (default = every 72 hours).
Explanation:
WordPress includes a "quick edit" function that lets users edit certain post properties (title, categories, etc) from the "All Posts" list. WP calculates the width (colspan attribute) of the inline editor based on the number of <th>'s in the header of the first .widefat table on the page. When PUC and Debug Bar are both active, that first table happens to be the debug info table in our Debug Bar panel. This table does not have a <thead>. As a result, WordPress sets the colspan to zero, making the inline editor unusable.
Fixed by removing the "widefat" class from our debug info tables and adding a bunch of new CSS to emulate WordPress table style.
When multiple instances of the update checker are active at the same time, each will have its own PluginUpdateCheckerPanel instance and its own entry in the Debug Bar. However, since all instances have the same class name, and Debug Bar uses this name to generate link and wrapper IDs, we will end up with duplicate IDs and a semi-broken debug bar.
I've added a bit of JS that will find update checker panels and replace the relevant IDs with new ones based on the plugin slug, not class.
Yahnis Elsts
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