The 'fields' query parameter for WP_Query supports only a string

[ocean90]

In the DocBlock of WP_Query::parse_query() the type of $fields is currently documented as string|array but it's only a string as it only accepts 'ids' and 'id=>parent'. Looks like it has been copied from WP_User_Query.

Related: #19866.

[johannadevos]

I have created a second patch which improves the first patch (44305.diff) in two ways:

• It fixes whitespace: in the first patch, $fields (and the description after it) on line 634 were one space character to the left of all of the other code.
• I have removed the text "or array of fields" from the $fields description.

[johannadevos]

Second patch that fixes whitespace and removes an irrelevant description

[noisysocks]

Thanks for the patch!

Reading the updated comment, it's not 100% clear to me that fields can be set to three and only three options:

• 'id' which makes the query return only e.g. post IDs.
• 'id=>parent' which makes the query return only e.g. post IDs and their parent IDs.
• Anything else, e.g. '', which makes the query return all fields.

Could we try to have the comment enumerate these options? Here's my suggestion:

Which fields to select. Accepts 'ids', which selects just the post ID; 'id=>parent', which selects just the post ID and the post_parent ID; and '', which returns all fields.

[ocean90]

44305.3.diff​ uses the same format as used in WP_Term_Query.

[davidbaumwald]

@ocean90 Is this still doable for 5.5?

[SergeyBiryukov]

In 48562:

Docs: Improve formatting of the $fields parameter description in WP_Term_Query::__construct().

See #44305, #49572.

[SergeyBiryukov]

In 48563:

Docs: Correct type and improve description for the $fields parameter of WP_Query::parse_query().

Props ocean90, palmiak, johannadevos, noisysocks.
Fixes #44305.