Add new param to {$new_status}_{$post->post_type} action

[sebastian.pisula]

I think, that $old_status is useful in this action.

[swissspidy]

Note that the DocBlock of that action recommends using the transition_post_status hook when needing to check the old and the new status. {$new_status}_{$post->post_type} can be called multiple times without the status having really changed.

[aaroncampbell]

I came up against this again recently, so I'm reopening the discussion. I do see that what @swissspidy says about using transition_post_status is accurate, but that fires for EVERY transitioned post of any type. There end up being a lot of calls to a function that basically starts with something like:

if ( 
    ( 'publish' === $new_status && 'publish' !== $old_status ) // first published
    && 'my-post-type' === $post->post_type // my-post-type post type
) {...}

It seems like being able to use the action that fires only for a specific post type (in this case publish_my-post-type) would be a lot more efficient and would only require that the old status be passed to the action, like it is to the other two (transition_post_status as another parameter and {$old_status}_to_{$new_status} as part of the dynamic name)

A big part of WHY this is a common use case where $old_status is needed, is that updating a post that's currently published will trigger these status transition actions, even though the status isn't really transitioning at all (publish -> publish). We're obviously a long way down that road, but another option that was brought up is that we could potentially add a new action that only fires if the old and new statuses are different.

It seems like passing the old status to the existing action is the easiest fix and basically gives it access to the same info that we supply to the other two.

[audrasjb]

Posts, Post Types: Add $old_status parameter to {$new_status}_{$post->post_type} action

[audrasjb]

36180.1.diff refreshes the previous patch.

[hellofromTonya]

Needs refresh and then should be ready for commit.

[audrasjb]

Posts, Post Types: Add $old_status parameter to {$new_status}_{$post->post_type} action.

[audrasjb]

Patch refreshed against trunk.

As per today's bug scrub, I'm marking this as ready for commit.

[hellofromTonya]

In 52067:

Posts, Post Types: Add $old_status parameter to {$new_status}_{$post->post_type} action.

Follow-up to [5797], [28106], [31461].

Props aaroncampbell, audrasjb, desrosj, johnbillion, sebastianpisula, swissspidy.
Fixes #36180.

[hellofromTonya]

Thank you everyone for your contributions! $old_status will now pass with the action in 5.9.