Inconsistent guard conditions in query.php

[vdankbaar]

While working on #55104 we noticed that other functions were also missing guard conditions.
In these cases, $wp_query could be null which would cause a fatal error. It would be safer to check if $wp_query is set before.

Fixed inconsistent guard conditions in query.php in line with; #55104

Trac ticket: https://core.trac.wordpress.org/ticket/55722

Hi there, thanks for the PR!

For reference, here is the list of functions affected by this change:

• have_posts()
• in_the_loop()
• rewind_posts()
• the_post()
• have_comments()
• the_comment()

I had some notes when looking at the initial commit:

• These functions are not exactly conditional tags like the other is_*() functions: is_single(), is_home(), etc. So the same _doing_it_wrong() messages referencing conditional tags are not quite accurate here.
• Not all of these functions have a return value, e.g. rewind_posts(), the_post(), or the_comment(). Introducing a return value seems a bit out of scope for this change and could use a separate discussion.

If the goal is to avoid a fatal error if $wp_query is not set, I would like to suggest doing just that and returning early. That might not necessarily be consistent with the other is_*() functions, but would be in line with the current return values of these particular functions. A _doing_it_wrong() message could then be considered later as a separate enhancement.

With that in mind, I have made some adjustments to the PR and added a unit test. Any thoughts are welcome 🙂

[SergeyBiryukov]

In 53429:

Query: Check if $wp_query is set in query loop functions.

This avoids a PHP fatal error if any of these functions are called too early:

• have_posts()
• in_the_loop()
• rewind_posts()
• the_post()
• have_comments()
• the_comment()

bringing some consistency with conditional tags: is_single(), is_home(), etc.

This commit also removes unnecessary return from the_comment(), for consistency with the_post(). As WP_Query::the_comment() does not have a return value, this statement did not have any effect in practice.

Follow-up to [4934], [8807], [16947], [17068], [17083], [49147], [53395], [53396], [53400].

Props vdankbaar, thijso, teunvgisteren, timkersten655, SergeyBiryukov.
Fixes #55722.

Merged in https://core.trac.wordpress.org/changeset/53429.