Custom post type single post feed returns a 404 if has_archive is set to false when calling register_post_type()

[henry.wright]

When using register_post_type(), the single post feed returns a 404 if has_archive is set to false. This seems to happen regardless of the value of feeds in the rewrite array. For example:

register_post_type(
    'example',
    array(
        'rewrite'     => array( 'slug' => 'my-custom-post-type', 'feeds' => true ),
        'has_archive' => false
    )
);

$ curl -IL https://example.com/my-custom-post-type/some-text/feed/
HTTP/1.1 404 Not Found

I'd expect a feed for the post to be built if feeds is set to true.

Note I have flushed permalinks.

[soulseekah]

Hey, thanks for your report.

This appears to be by design. Types that have no archive will not create feed endpoints as you would expect.

Singe post and page feeds are comment feeds and are created separately inside WP_Rewrite::rewrite_rules, specifically in WP_Rewrite::generate_rewrite_rules.

By extension, you are able to create your own custom feed rules on single types by using WP_Rewrite::generate_rewrite_rules and hooking into the rewrite_rules_array filter.

A quick fix would be to do:

add_action( 'rewrite_rules_array', function( $rules ) {
	global $wp_rewrite;
	$wp_rewrite->add_rewrite_tag( '%my-custom-post-type%', 'my-custom-post-type/([^/]+)', 'example=' );
	$custom_rules = $wp_rewrite->generate_rewrite_rules( '%my-custom-post-type%', EP_NONE, true, true, false, false );
	return $custom_rules + $rules;
} );

This will generate the needed feed. I am working on a leaner patch.

P.S.: The Rewrite API is insane to work with.

[soulseekah]

43746 is an attempt at providing this feature in register_post_type by introducing a rewrite key called single_feed which doesn't care about the has_archive property.

[SergeyBiryukov]

Replying to henry.wright:

I'd expect a feed for the post to be built if feeds is set to true.

I agree, I don't think we need a new argument here.

The existing feeds argument could be updated to support single post (comments) feed. If has_archive is disabled, it would be the only feed generated.

@soulseekah Thanks for the patch! Could you update it to decouple the feeds argument from has_archive?

[mattkeys]

Just to add to this discussion, I found this ticket when searching for solutions to why a 404'ing feed is being added to the head on a site I manage.

The comments feed link tag seems to be added to the head so long as comments are open on the post type, which they are. However because I have has_archive set to false, the feed 404's, creating SEO/Crawl issues. After reading the docs on 'register_post_type' I found the 'feeds' param under rewrites and set it to true, expecting it to fix the problem, but it did not, and I eventually found my way here.

[mattkeys]

I just added a new patch that would allow for the expected behavior of feeds => true, decoupling it from has_archive.

A new ticket will probably need to be opened to prevent the comment feed link tag from being added to the head on sites when comment feed permalinks are not being generated because has_archive = false and feeds = false.

[peterwilsoncc]

Moving to the 5.1 milestone due to the WordPress 5.0 focus on the new
editor (Gutenberg).

[pento]

Patch needs testing and review.