get_terms() assumes its taxonomies argument is a numeric array with a 0 key

[nbachiyski]

In a few places in get_terms() we are using $taxonomies[0] after we've established that we have more than one taxonomy. The array isn't always 0-based, though.

For example, get_taxonomies() returns arrays with the taxonomy name as a key, which breaks this pattern.

In the attached patch, the taxonomies are run through array_values(), which gives us a 0-based array of the taxonomies.

[nbachiyski]

Test in ​[UT1219].

[Viper007Bond]

Fixing ticket title to clearer terminology. Probably worth updating the patch too.

[nbachiyski]

I still think 0-based is the better term.

The array, which is a result of $a = array( 1, 2, 3); unset( $a[0] ); is still numeric, but its zeroth element is missing.

[Viper007Bond]

Replying to nbachiyski:

I still think 0-based is the better term.

The array, which is a result of $a = array( 1, 2, 3); unset( $a[0] ); is still numeric, but its zeroth element is missing.

True!

[markjaquith]

Seems prudent. Alternatively (or even additionally), we could start using using the proper array function to grab the first item, instead of [0] (i.e. current(), or even list()).

[webord]

Using reset to get the first Item of the array

[wonderboymusic]

+ whitespace in the refresh

[wonderboymusic]

this passes all unit tests

[nacin]

Since we're adjusting whitespace, $hierarchy[$child_of] should be $hierarchy[ $child_of ] — for some time we have put spaces here when the key is a variable.

[wonderboymusic]

In 25108:

Use reset() to grab the first taxonomy in an array, not by numerical index. Cleans up whitespace. Props webord, nbachiyski. Fixes #23506.

[boonebgorges]

In 40924:

When querying for terms, do not assume that $taxonomies is a 0-indexed array.

In [25108], the logic of term queries was modified to avoid assuming
that the taxonomies array was numerically indexed. See #23506. This
fix was inadvertantly reverted during the refactor in [25162].

Props david.binda.
Fixes #41113.