fix(migration): stop using the removed IIndex::hasColumnAtPosition()

[solracsf]

Nextcloud 35 reduced the schema API surface and dropped hasColumnAtPosition() from OCP\DB\Schema\IIndex, which fails the static-psalm-analysis dev-master job with four UndefinedInterfaceMethod errors in this migration.

Use getColumns() instead, which exists both on the new IIndex and on the Doctrine index objects still returned by Nextcloud 29 to 34, and compare the first column the way Doctrine did, unquoted and case insensitively, so the behaviour is unchanged on every supported server version.

[CarlSchwan]

We can add hasColumnAtPosition back

[solracsf]

Happy either way, though I don't think it needs to come back just for this.

There's also an argument for leaving it out. Index::hasColumnAtPosition() is deprecated in doctrine/dbal 4.4 in favour of getIndexedColumns(), and it's built on top of getUnquotedColumns() and getColumns(), which are deprecated in the same release.

Putting it back on IIndex would tie a public @since API to something DBAL is already retiring.

Your call here.

[CarlSchwan]

Done in nextcloud/server#63152 this would obsolete your PR

[solracsf]

Feel free to close it once merged :)

[CarlSchwan]

Merged