Prevent flushing rewrites during page load

[joostdevalk]

Flushing rewrites during the pageload breaks a lot of plugins. They might not have registered their rewrite yet which would cause issues. I propose preventing the flushing from working and forcing it to be run on shutdown instead.

[joostdevalk]

Related to but not the same as #29118.

[rmccue]

I'm +1 on adding this, for sure. I don't think there's any issues with changing this that I can see.

(Note that this solves a different problem to the one I'd discussed previously in ticket:29118#comment:5: I was aiming to avoid ever calling flush rewrites, whereas the problem here is the infamous flush-before-registration.)

[joostdevalk]

Just updated the patch to check for did_action( 'init' ) so you can't flush too early anymore, but the flush would still work on the current pageload.

[joostdevalk]

Original patch

[joostdevalk]

Patch for did_action( 'init' )

[mboynes]

@joostdevalk, how about pushing this out of init, perhaps to wp_loaded? I can imagine plenty of plugins may register rewrites after priority 10 of init, and this patch wouldn't solve this problem for them. wp_loaded is the last action that fires before WP::parse_request() (where the rewrite rules are used), so it seems like a decent time to regenerate should that be requested.

[joostdevalk]

Good point @mboynes, uploading new patch.

[joostdevalk]

Rewrite to wp-loaded patch (v3)

[rmccue]

rmccue approves! If we're going to do this (and we should), let's try and do it early in 4.2 so that we find any plugin breakages as soon as possible.

[SergeyBiryukov]

In 31104:

If WP_Rewrite::flush_rules() is called on 'init' or earlier, wait until 'wp_loaded' before actually flushing the rules, to make sure all the rules registered on 'init' are included.

props joostdevalk.
see #30501.

[pavelevap]

I am not sure if I understand it well, please see example code:

function some_rewrite() {
  global $wp_rewrite;
  $wp_rewrite->author_base = 'something';
  $wp_rewrite->flush_rules();
}
add_action('init', 'some_rewrite');

Calling $wp_rewrite->flush_rules() is wrong here because it is called during every page load. What is the right way for users when they want to change author to something else? And they need only quick hack for functions.php (and not flushing rewrite rules during plugin activation).

I saw many times this piece of code. It will work in 4.2 and only running $wp_rewrite->flush_rules() function will be automatically moved to wp_loaded?

[joostdevalk]

Flushing on every page load is still bad and this patch does not prevent that. What this DOES prevent is a plugin or theme running flush_rewrite_rules before plugins have had a chance to register their rewrites, which causes URLs to break. So it doesn't prevent it from running, it just moves it.

[Funkatronic]

Replying to joostdevalk:

Flushing on every page load is still bad and this patch does not prevent that. What this DOES prevent is a plugin or theme running flush_rewrite_rules before plugins have had a chance to register their rewrites, which causes URLs to break. So it doesn't prevent it from running, it just moves it.

Is add_action smart enough to call flush_rewrite_rules only once vs the n amount of calls various plugins will do?

[SergeyBiryukov]

Replying to Funkatronic:

Is add_action smart enough to call flush_rewrite_rules only once vs the n amount of calls various plugins will do?

Yes.

[SergeyBiryukov]

[31104] seems to work as expected.

[Denis-de-Bernardy]

Replying to SergeyBiryukov:

[31104] seems to work as expected.

Is there any reason for dumping the $hard argument? From the looks of the changeset, if you try to do a soft flush before wp_loaded, you'll end up doing a hard one later on instead.

[SergeyBiryukov]

Good point.

[Denis-de-Bernardy]

A possible workaround off the top of my head:

static $do_hard_later;

if ( ! did_action( 'wp_loaded' ) ) { 
  add_action( 'wp_loaded', array( $this, 'flush_rules' ) );
  $do_hard_later ||= $hard;
  return; 
}
elseif ( isset( $do_hard_later ) && doing_action( 'wp_loaded' ) ) {
  $hard ||= $do_hard_later;
  $do_hard_later = null;
}

[DrewAPicture]

@Denis-de-Bernardy: Would you care to follow up with a patch? It seems solving the $hard issue is the only thing preventing this ticket from being resolved in 4.2.

[mordauk]

30501.patch should take care of the $hard issue.

[DrewAPicture]

spacing

[SergeyBiryukov]

30501.2.patch​ doesn't account for a situation where flush_rules() is called with $hard = true and then with $hard = false. It would only do a soft flush in that case.

30501.3.patch​ fixes that.

[SergeyBiryukov]

In 31964:

When shifting WP_Rewrite::flush_rules() to a later action if it was called too early, make sure to do a hard flush if requested.

props Denis-de-Bernardy, mordauk for initial patch.
fixes #30501.

[selnomeria]

please, tell the world (all plugins developers, in a big RED NOTICE, that they should disable flushing on every page load...
they'd better to use smth like this:
if (get_option("my_checkpoint_12345")) {

....flush...
....delete_option("my_checkpoint_12345");........

}

[dd32]

#32023 was marked as a duplicate.