No need to define $matches when using preg_match and preg_match_all

[kovshenin]

I noticed that some of the new code in 3.6, especially around post formats, defines an empty $matches variable when using preg_match and preg_match_all. This is not required and we don't do it in a lot of other places in core.

[kovshenin]

Went through all the codebase in search of these (except external libraries), my findings are in 24222.diff​.

[nacin]

In 24129:

Variables passed by reference do not need to be set first.

props kovshenin.
see #24222.

[nacin]

In 24130:

Better logic for preg_match() calls in ms-functions.php. fixes #24222.