Post Excerpt Block: Remove REST API filter for excerpt length in post excerpt block

[SirLouen]

What?

@xavier-lc has noticed that despite the excerpt is being showed correctly now in both Editor and Front-end the behaviour in the REST-API is buggy.

Why?

#74140 introduced some changes in the admin checks, but also added a little bug.

How?

Removing the filter to rest_api also fixes the problem.

Testing Instructions

1. Create two posts
2. Add content in the two posts, a good amount of words, 200 words at least
3. Add a manual excerpt to one of the two posts, be sure to add a good amount of text, 200 words at least
4. I recommend using TT3 theme
5. Now set the excerpt lenght to something like 70 words
6. Check if:
7. In the frontend you see 70 words for the automatic excerpt
8. In the backend you see 70 words for the automatic exceprt
9. In an API call like: `curl -s -u 'your_api_creds' "http://localhost:8889/?rest_route=/wp/v2/posts/POST_NUMBER&context=edit&_fields=excerpt&excerpt_length=20" you see 70 words for the excerpt (THIS IS WHAT THIS FIX IS TARGETTING)
10. In the front end you see 70 words for the manual excerpt
11. In the backend you see 70 words for the manual excerpt
12. In the API you see all the words you added to the excerpt in the manual exceprt (expected behaviour? it seems that limit doesn't affect in the API for manual excerpt, but this beyond our scope)

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Co-authored-by: SirLouen <sirlouen@git.wordpress.org>
Co-authored-by: ntsekouras <ntsekouras@git.wordpress.org>
Co-authored-by: xavier-lc <xavilc@git.wordpress.org>
Co-authored-by: ellatrix <ellatrix@git.wordpress.org>

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[SirLouen]

I was planning to add some unit tests for all these 6 scenarios after the patch in #74140 but I did not find the time to settle into them.

[ntsekouras]

In an API call like: `curl -s -u 'your_api_creds' "http://localhost:8889/?rest_route=/wp/v2/posts/POST_NUMBER&context=edit&_fields=excerpt&excerpt_length=20" you see 70 words for the excerpt (THIS IS WHAT THIS FIX IS TARGETTING)

I'm a bit confused about what we're trying to solve. Shouldn't the REST request always respect the excerpt_length param?

[xavier-lc]

The fix works for me, returning the word count requested on the excerpt_lengthparam of the API call. Not the the request I'm using ishttp://localhost:8888/wp-json/wp/v2/posts/35?context=edit&_fields=excerpt&excerpt_length=10`, a bit different from the http://localhost:8889/?rest_route=/wp/v2/posts/POST_NUMBER&context=edit&_fields=excerpt&excerpt_length=20 used on the description:

cc @SirLouen @ntsekouras

[ellatrix]

Btw, I committed this yesterday to fix the unit tests in core: https://github.com/WordPress/wordpress-develop/pull/10865/changes#r2783019829

[SirLouen]

Btw, I committed this yesterday to fix the unit tests in core: https://github.com/WordPress/wordpress-develop/pull/10865/changes#r2783019829

@ellatrix I can see this commit
WordPress/wordpress-develop@f8b2285

I'm testing and that is also fixing the automatic excerpt generation because it goes on top of this PR. It also shows the […] symbol

But this PR here is not really going to be fixing anything now, but simply removing some extra code that has been rendered useless now as its not doing anything.

On a side note, what @ntsekouras comments is another thing that I'm not sure if it is a problem or if it is expected.

Testing Instructions

1. Create a new Post
2. Add a long Excerpt, for example 200 words. Get the Post ID for the post created. Lets say its the post ID 100
3. Create an application password. Let say is 1234 1234 1234 1234 for the user admin
4. Limit the API query:

curl -s -u 'admin:1234 1234 1234 1234' "http://localhost:8889/?rest_route=/wp/v2/posts/100&context=edit&_fields=excerpt&excerpt_length=20"

Result: 200 words
Despite the excerpt_lenght is being limited to 20

If we limit to 20 words in the slider control for this same post, it will show 20 words both in the rendered from and in the back end.

Type	Display	Total Words	Limit	Result
Manual	Frontend	200	20	20
Manual	Editor	200	20	20
Manual	REST API	200	20	200*
Automatic	Frontend	200	20	20
Automatic	Editor	200	20	20
Automatic	REST API	200	20	20

*Checking the code, the problem is that

https://github.com/WordPress/wordpress-develop/blob/81885a9ff64f3902d4f3162c011745a35b46e6ba/src/wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php#L1996

Is being invoked in default filters with wp_trim_excerpt which only do the trimming on if ( '' === trim( $text ) ) { in
https://github.com/WordPress/wordpress-develop/blob/81885a9ff64f3902d4f3162c011745a35b46e6ba/src/wp-includes/formatting.php#L3958

So basically with an excerpt not empty (the manual one), no trimming will happen regardless of how we manipulate the filters.

So basically I would simply pass this PR as it's simply removing useless code after the PR sent by @ellatrix

[ntsekouras]

Thanks @SirLouen for the PR and the investigation for my comment:

Shouldn't the REST request always respect the excerpt_length param?

That helped me track and investigate the issue faster and it seems it's a core issue and we should open a trac ticket to discuss whether that's intended or not. My personal opinion is that we should respect it with manual excerpts too, but core folks might share context or possible nuances for that.

Let's land this one for now.

[bph]

Backported to 22.5.3.