Typo in wp_title separator placeholder

[morganestes]

The placeholder separator within wp_title() is %WP_TITILE_SEP%. A contributor to the Code Reference noticed the typo and wanted to confirm if it was an issue with the code itself or the reference page, so I'm confirming here it's in the code and wonder if it needs to be fixed since it's now in the reference.

See https://core.trac.wordpress.org/browser/trunk/src/wp-includes/general-template.php#L998 for the details.

[DrewAPicture]

For reference, this typo has been in place for since [9376] (7 years). Kind of makes you wonder why it was never previously caught. I think we could benefit from unit tests here.

[morganestes]

I suspect it was never caught because it's only used by that one function. I'll check the theme and plugin repos to see if I can find any reference to it, but suspect I'll come up empty.

What kind of tests can we write for it?

UPDATE: Although it's not filterable, it's passed to 'wp_title_parts', so that's where I'm going to start looking.

[SergeyBiryukov]

Replying to DrewAPicture:

For reference, this typo has been in place since [9376] (7 years). Kind of makes you wonder why it was never previously caught.

FWIW, I've seen it before, but thought it was some kind of a legacy thing :)

[nacin]

This is amusing.

[morganestes]

Replying to nacin:

This is amusing.

It's a minor issue, but it was noticed and questioned when someone caught it while using the Developer Resources site.
I figure that's a win for DevHub, plus a good chance to learn about testing legacy code. Sure, it may not be high priority for fixing, but it's a great learning opportunity for new contributors.

[morganestes]

Replying to morganestes:

I suspect it was never caught because it's only used by that one function. I'll check the theme and plugin repos to see if I can find any reference to it, but suspect I'll come up empty.

UPDATE: Although it's not filterable, it's passed to 'wp_title_parts', so that's where I'm going to start looking.

Ran through the theme and plugin repos; the filter's not used in any theme, but it's used in 6 plugins, although the separator isn't specifically modified in any of them.

[dossy]

The $t_sep value shouldn't really be testable since it's an internal implementation detail of the function, not meant to be exposed to any caller. However, if you really want tests that fail given the current typo, I can write one - although, it'll be very tightly coupled to the specific implementation of wp_title() and not really be testing the higher-level functionality (e.g., if wp_title() is refactored, the test will fail but the function could still likely be doing the right thing in general).

Really, shouldn't wp_title()'s implementation get rewritten to use the new wp_get_document_title() in 4.4?

Anyway, I've uploaded 34879-2.patch​ which adds a test that will fail without the "fix" if that helps.

[mrahmadawais]

Good catch @morganestes :)

[ocean90]

In 36540:

In wp_title() fix a 7 year old typo.

Props joelerr.
Fixes #34879.