Since 4.4, comment submission has been mostly abstracted into a function,
rather than being processed inline in wp-comments-post.php. This change
made it easier to write automated tests against the bulk of the comment
submission process. `wp_allow_comment()` remained untestable, however:
when a comment failed one of its checks (flooding, duplicates, etc),
`die()` or `wp_die()` would be called directly. This shortcoming posed
problems for any application attempting to use WP's comment verification
functions in an abstract way - from PHPUnit to the REST API.
The current changeset introduces a new parameter, `$avoid_die`, to the
`wp_new_comment()` stack. When set to `true`, `wp_new_comment()` and
`wp_allow_comment()` will return `WP_Error` objects when a comment check
fails. When set to `false` - the default, for backward compatibility -
a failed check will result in a `die()` or `wp_die()`, as appropriate.
Prior to this changeset, default comment flood checks took place in the
function `check_comment_flood_db()`, which was hooked to the
'check_comment_flood' action. This design allowed the default comment
flood routine to be bypassed or replaced using `remove_action()`.
In order to maintain backward compatibility with this usage, while
simultaneously converting the comment flood logic into something that
returns a value rather than calling `die()` directly,
`check_comment_flood_db()` has been changed into a wrapper function for
a call to `add_filter()`; this, in turn, adds the *actual* comment flood
check to a new filter, 'wp_is_comment_flood'. Note that direct calls
to `check_comment_flood_db()` will no longer do anything in isolation.
Props websupporter, rachelbaker.
Fixes#36901.
git-svn-id: https://develop.svn.wordpress.org/trunk@38778 602fd350-edb4-49c9-b593-d223f7449a82
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