[policy, no patch] Remove old update hooks prior to each major version (Drupal 10 and later)

Re-titling.

Quoting some discussion from 📌 [policy] Remove update hooks added until 10.3 from Drupal 11 RTBC .

Gábor Hojtsy

Now that Drupal 10 will be supported until the Drupal 12 is released, would it not be in line with that intent to keep the update functions instead? I understand that removing the upgrade functions is standard practice, but https://www.drupal.org/blog/drupal-10-will-be-supported-until-the-releas → ... would be counter to that?

@catch:

There are three reasons to remove older update functions:

1. To encourage sites to update contributed modules to 11.x-compatible versions before updating core to 11.x. i.e. sites on 10.3.x with updated contrib modules are much more likely to update to 11.0.x successfully than sites on 10.0.0 trying to jump all the way to 11.x and updating their contrib modules at the same time.

Sites on 10.0 may not be able to update contrib modules to 11.x compatible versions at all (if they rely on APIs added in 10.1 or 10.2), and they also may struggle to composer update contrib + core all the way from 10.0 to 11.0, because updating lots of composer dependencies at the same time gets very, very complicated.

2. To minimize the number of (core and contrib) update functions that can potentially have to run in the same update, for example if a site tried to update all the way from 10.0.0 to 11.6.0 (which would represent 4-5 years of core development) there could be tens of updates that need to run, config that gets updated multiple times for different changes etc. The more updates can potentially run, the more likely it is that we end up with dependency issues where update X has to run before update Y but after update Z and similar.

3. To reduce the matrix of update paths that we don't have test coverage for. e.g. ideally we'd have test coverage for 10.3-11.0, 10.4-11.0, 10.5-11.0, 10.3-11.1, 10.4-11.1, 10.5-11.1, 11.0-11.1 etc. but we don't have anything like that and can't add it with the current update test infrastructure.

I think that #1 is about the same with 10-11 as it was for 9-10. But #2 and #3 will actually be worse with two active branches, since we'll have more total minor releases to juggle, more updates paths to potentially backport between major versions (or not), and more potential paths to for people to take between different combinations of versions.

Or tl;dr, we've said that 10.x will be supported until Drupal 12.0, but we didn't say that Drupal 10.0 will be supported until 12.0.

fwiw I discussed #7 briefly with Gábor in slack and we realised that removing updates from 10.0-10.3 from 11.x doesn't preclude updating from Drupal >= 10.3 to 12.0.

That will depend on the functions added from 10.4/11.0 onwards and when those get removed. e.g. there could be a situation where you can update from 10.6 and 11.4 to 12.0, but not from 10.5 and 11.3. Or it could be that you can update only from 11.4+ to 12.0 - it all depends what gets backported to Drupal 10 minor releases, and what the cut-off point is. This doesn't automatically mean we'll support a Drupal 10-12 update path, but it adds an extra thing to think about in #2942096: [policy, no patch] Remove old update hooks prior to each major version (Drupal 10 and later) and is unaffected by this issue.

What this issue will do is prevent direct updates from Drupal 9.5-10.2 to Drupal 11.

I've updated the issue summary with a better explanation of why this happens, the pattern we've followed for 8-9, 9-10 and 10-11, and how this might look when we have 10/11/12 branches all open at the same time.

Since this is de-facto what we've been doing every major release, successfully, for several years now, going to go ahead and mark RTBC. We might want a new issue to track 10.x update backports from 11.x which is its own not small can of worms.

This change can be added to https://www.drupal.org/about/core/policies/core-change-policies/continuo... →

Update functions added to the minor release that coincides with the first release window of the next major version are removed. After Drupal 11, this changes so that update functions added to the minor release that coincides with the major release are removed.

This issue has a change record, it doesn't seem to me that it is still needed?

I removed this issue from the change record, the CR is still valid for the other issues it was attached to.

For what it's worth, after seeing the D9 and D10 upgrade paths, I've come around to agreeing strongly with @catch's recommendation.

I also agree with tracking upgrade path backports; tagging for a followup for that. I guess it would be a child of the D12 meta tree which may also need creation still?

Removing the RM tag since we all agree on this.

I was going to open a new issue for the 11.x and 10.x update path co-ordination, then I thought I'd better reference 📌 Handling update path divergence between 11.x and 10.x Fixed , then I realised nothing has changed. Have updated the issue summary there with the new major version numbers. Let's use that one.

I see how this improved our stability and made our life less complicated. I also think its a far fetched idea that Drupal 10.x users would update to 12.x in place, that would require all of their contribs to somehow support that update too. So we don't need to bend over backwards to support that. Let's consider this policy agreed and refine the update functions if/when we have feasibly backportable solutions.

Automatically closed - issue fixed for 2 weeks with no activity.