wp_can_install_language_pack(): Direct access to $upgrader->fs_connect() can produce undefined index notices

[ocean90]

Example: Notice: Undefined index: fs_no_content_dir in /src/wp-admin/includes/class-wp-upgrader.php on line 182

That's because the init() method isn't called here, which sets up the strings. We should either do $upgrader->init() or $upgrader->generic_strings().

[nacin]

I see no harm in fixing or not fixing this in 4.1.1.

[valendesigns]

@ocean90 What are the steps to reproduce the notices? I want to test your patch but am having trouble getting PHP to throw a notice during language pack installation.

[SergeyBiryukov]

In 31074:

Call the init() method for the upgrader in wp_can_install_language_pack() to avoid undefined index notices.

props ocean90.
fixes #30827 for trunk.

[dd32]

I'm so-so on including this in 4.1.1, I could go either way, unless someone feels strongly, lets close it on 4.2.

Realistically, it's only a PHP notice, and none of the strings missing should be needed during a translation install, it's also unlikely any other alterations will be made to this file in 4.1.1 (meaning one less file in a 4.1 -> 4.1.1 update).

Worst case, as @ocean90 hit here, the upgrade can't find the wp-content directory and it emits a PHP notice + fs_no_content_dir instead of a human-readable message.. a case that should be exceedingly rare.