fix(lidarr): send artistId (singular) so ArtistSearch actually runs

[Germwalker]

Problem

Lidarr's missing-mode artist never triggers a real search. Every ArtistSearch command is silently rejected by Lidarr, while Newtarr logs it as a success.

In src/primary/apps/lidarr/api.py, the command payload is built with a plural key:

payload = {
    "name": "ArtistSearch",
    "artistIds": [artist_id]
}

Lidarr's ArtistSearchCommand exposes a single integer field, ArtistId — there is no ArtistIds. Lidarr's JSON deserializer ignores the unknown key, ArtistId keeps its default value of 0, and the command fails at execution time:

NzbDrone.Core.Datastore.ModelNotFoundException: Artist with ID 0 does not exist
   at NzbDrone.Core.IndexerSearch.ReleaseSearchService.ArtistSearch(Int32 artistId, ...)

Newtarr never sees this: POST /api/v1/command returns 201 with a command id, so it logs Triggered Lidarr ArtistSearch for artist ID: 1261 and moves on. The failure happens later, when Lidarr executes the queued command. The artist id is computed correctly — it is only lost when the payload is built.

The same file already uses the singular form correctly elsewhere (params['artistId'] = artist_id, line 195), which suggests a typo rather than a deliberate choice. search_albums() is unaffected: it sends albumIds, which does match AlbumSearchCommand.AlbumIds (a List<int>).

Fix

Send the field Lidarr actually declares.

Verification

Applied on a live instance (Lidarr, 3546 artists, ~57k missing albums).

Before — 30 of 30 searches per cycle failed, none reached an indexer:

10:33:11 |Error|CommandExecutor|Error occurred while executing task ArtistSearch
          ModelNotFoundException: Artist with ID 0 does not exist   (x30)

After — searches reach the indexers:

10:49:29 |Info|ReleaseSearchService|Searching indexers for [Nathaniel Rateliff]. 14 active indexers

No further Artist with ID 0 entries after the restart.

Impact

Anyone running Newtarr against Lidarr with hunt_missing_mode: "artist" gets zero results while the logs report normal operation. The bug predates this fork — the same line is present in the upstream Huntarr code.

🤖 Generated with Claude Code

https://claude.ai/code/session_01LMKFGWjW2FQSQPCcQ4mWLC