This is confusing. As far as I understand things, the cusi_case table is only supposed to exist on x1 on wikis where Suggested Investigation is enabled, and kajwiki is not such a wiki.

Yeah, it doesn't exist on that wiki. But it seems that running the schema updates from LoadExtensionSchemaUpdates isn't something we do on WMF wikis? My understanding is that the update.php command is not run on production at all, though maybe this is from install.php?

As for solving this problem:

• We lack the ability to read extension config in install.php, so cannot be sure if the feature is or is not enabled during install
  • Therefore, we unconditionally create the database table on the virtual domain and apply schema updates to it
• The user seems to have the ability to create the cusi_case table, as the table is created before this line so it likely already has this update applied
  • Maybe we can have a more restrictive modifyField check to see if the field already has been modified in the specified way? Then we wouldn't see the error when creating new wikis (though the database table would still be created)

@Urbanecm_WMF where is the above log snippet from? Is it from addWiki.php running install.php?

If so, then I don't think I see exactly what Product Safety and Integrity can do here because we need the schema changes to be applied when running install.php for wikis that may have the feature enabled. As mentioned above, we cannot skip creating the database tables based on CheckUser configuration values (as config is not accessible during install.php)

Skipping just the ALTER TABLE commands for install could work (because the CREATE TABLE command should have already been applied to the initial definition of the table). However, skipping modify field commands on install feels like an issue that should be fixed in MediaWiki core because:

• This does not seem specific to CheckUser, as any run of install.php for any other code which modifies a field in a database table will have the schema change run AFAICS
  • Therefore, CheckUser is just a symptom of the wider issue that addWiki.php should not run schema updates. Whether that means no install.php or making it possible to skip schema updates during install.php, I am not sure

In T415555#11558634, @Dreamy_Jazz wrote:

@Urbanecm_WMF where is the above log snippet from? Is it from addWiki.php running install.php?

Yes.

If so, then I don't think I see exactly what Product Safety and Integrity can do here because we need the schema changes to be applied when running install.php for wikis that may have the feature enabled. As mentioned above, we cannot skip creating the database tables based on CheckUser configuration values (as config is not accessible during install.php)

Skipping just the ALTER TABLE commands for install could work (because the CREATE TABLE command should have already been applied to the initial definition of the table). However, skipping modify field commands on install feels like an issue that should be fixed in MediaWiki core because:

• This does not seem specific to CheckUser, as any run of install.php for any other code which modifies a field in a database table will have the schema change run AFAICS
  • Therefore, CheckUser is just a symptom of the wider issue that addWiki.php should not run schema updates

As I've said above, this is an issue stemming from running install.php to run schema updates and isn't the fault of CheckUser per-se. We cannot simply read CheckUser config during install.php to know if the table should be created, as it is not available. Additionally, cusi_case shouldn't be created either IMO.

Therefore, the only solution I see that we could take in CheckUser is to never create cusi_case when running install.php and only then create it once update.php is run. That is hacky, but it unblocks this issue for creating more wikis because AFAIK update.php is never run in production

Change #1240923 had a related patch set uploaded (by Dreamy Jazz; author: Dreamy Jazz):

[mediawiki/extensions/CheckUser@master] SI: Don't run DB updates during install or when not enabled

https://gerrit.wikimedia.org/r/1240923

Change #1240923 abandoned by Dreamy Jazz:

[mediawiki/extensions/CheckUser@master] SI: Don't run DB updates during install or when not enabled

Reason:

Doesn't work. See task for why

https://gerrit.wikimedia.org/r/1240923

That doesn't work because InstallPreConfigured does not use install.php and instead runs the DB updates directly. It is plausible that config will exist when this is running and so we can't easily detect when we shouldn't be attempting to make schema updates.

Additionally, in CI the Suggested Investigations feature is disabled by default. Without adding something to DevelopmentSettings.php, this means we cannot skip creating SI tables.

Instead, I see no way to fix this in CheckUser and MediaWiki core will need to be updated to just skip all ALTER TABLE commands when using InstallPreConfigured

Change #1240964 had a related patch set uploaded (by Dreamy Jazz; author: Dreamy Jazz):

[mediawiki/core@master] ExtensionTablesTask: Skip schema ALTER updates

https://gerrit.wikimedia.org/r/1240964

The above patch will:

• Skip all schema updates for extensions during install.php, which prevents the errors about ALTER TABLE not being run
• Run the skipped updates when update.php is run, which should have no effect other than creating an updatelog for them (though if the initial CREATE TABLE command is out of sync to what the schema updates apply, then this is necessary to ensure the schema is fully up to date)

To recap why this is necessary:

• During install.php, config will not necessarily be available for extensions and so we cannot alter/create tables depending on the value of a configuration value
• On WMF wikis, any ALTER TABLE command that is run during install.php will fail as the user does not have permission to alter tables (only to create them)
  • Therefore, this isn't specific to CheckUser or extensions in general and the issue is best fixed by ensuring that no ALTER TABLE command could run on WMF wikis during a run of install.php

Change #1240976 had a related patch set uploaded (by Dreamy Jazz; author: Dreamy Jazz):

[mediawiki/extensions/WikimediaMaintenance@master] addWiki.php: Skip ALTER TABLE updates during install

https://gerrit.wikimedia.org/r/1240976

Change #1240964 merged by jenkins-bot:

[mediawiki/core@master] ExtensionTablesTask: Allow skipping schema ALTER updates

https://gerrit.wikimedia.org/r/1240964

Change #1240976 merged by jenkins-bot:

[mediawiki/extensions/WikimediaMaintenance@master] addWiki.php: Skip ALTER TABLE updates during install

https://gerrit.wikimedia.org/r/1240976