Upgrade from 4.2.2 produces a warning on upgrade

[lordspace]

Warning: Invalid argument supplied for foreach() in /sites/test1.eagle.servers.qsandbox.com/htdocs/wp-admin/includes/update-core.php on line 1252

[atomicjack]

Did you have wp_debug on or not? Using any plugins or custom themes?

[pento]

I can see how this warning would've happened, it doesn't need any custom plugins/themes, though it will need WP_DEBUG enabled.

This warning will also occur when upgrading to 4.3, so we should fix it before 4.3 is released, and backport to the 4.2 branch.

[kitchin]

For the patch, I grepped all glob( and skipped SimplePie/Misc.php. Maybe that is an upstream or we want a warning there, don't know. Note (array)false = array(false). Also, as PHP says, "On some systems it is impossible to distinguish between empty match and an error." The glob() emulator in includes/class-ftp.php returns false or array, like PHP.

I don't see any unit tests.

[dmchale]

+1 for this patch. We do not have WP_DEBUG enabled anywhere, but noticed some of our sites never automatically updated to 4.2.3 - upon investigating, we found this PHP warning littering the error_log. Logging into the admin area and clicking to upgrade successfully worked, however.

As kitchin said, the php docs definitely mention the possibility of this issue on some systems, per the "Note" blockquote under Return Values. For the most broad system compatability, you can't simply trust a glob() inside a foreach() ​http://php.net/manual/en/function.glob.php

[markjaquith]

whitespace cleanup

[markjaquith]

In 33447:

Don't blindly trust the output of glob() to be an array.

props kitchin
fixes #33093

[samuelsidler]

We're going to backport this if/when we have a 4.2.4.

[pento]

In 33481:

Don't blindly trust the output of glob() to be an array.

Props kitchin.

Merge of [33447] to the 4.2 branch.

Fixes #33093.