Collections synced their names and arrived empty on every device. The names are
keyed on a uuid and worked; the membership union was keyed on
`images.content_hash`, and the schema says plainly what that column is:
"computed only when something needs it (import dedup, reconnect-by-hash), never
in a scan". A library that has only ever been scanned has one for no image at
all, so the join matched nothing and `WHERE ri.content_hash IS NOT NULL`
discarded whatever survived. The union could never have moved a single row.
Measured on a real catalog: 23,174 images, content hashes for 0 of them,
`oc:fileid` for all 23,174, twelve collections, zero members.
So membership now resolves through the file id first, exactly as keyword
assignment already did — `ASSIGN_BY_FILE_ID` was added for this same reason and
its doc comment even notes that membership was still on the hash. It is
recorded for every image the moment a remote scan sees it, survives server-side
rename and move (FR-NC-5), is the same integer on every device pointed at one
Nextcloud, and is already what the thumbnail shards are keyed by.
The content-hash union is kept rather than replaced: a local-only library has no
`remote` rows, and where a hash has been computed it is a true identity that
survives a library moving between servers. Both statements run; `INSERT OR
IGNORE` against the primary key makes the overlap free.
This repairs the merge. It cannot invent membership that no device recorded —
where the rows were never written, collections stay empty until they are filled
in again.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
dtourolleandClaude Opus 5
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