Fix duplicate attachment sync upserts

internal/store/attachments_test.go

@@ -90,6 +90,39 @@ func TestAttachmentMediaUpdatesAndFilters(t *testing.T) {
 	require.Empty(t, rows)
 }
 
+func TestAttachmentUpsertMovesDuplicateIDAndKeepsMedia(t *testing.T) {
+	ctx := context.Background()
+	s, err := Open(ctx, filepath.Join(t.TempDir(), "discrawl.db"))
+	require.NoError(t, err)
+	defer func() { _ = s.Close() }()
+
+	require.NoError(t, seedAttachmentForGuild(ctx, s, "g1", "c1", "m1", "a1"))
+	require.NoError(t, s.UpdateAttachmentMedia(ctx, AttachmentMediaUpdate{
+		AttachmentID:  "a1",
+		MediaPath:     "attachments/aa/hash-file.png",
+		ContentSHA256: "hash",
+		ContentSize:   4,
+		FetchedAt:     "2026-05-15T12:05:00Z",
+		FetchStatus:   "fetched",
+	}))
+	require.NoError(t, seedAttachmentForGuild(ctx, s, "g1", "c2", "m2", "a1"))
+
+	rows, err := s.ListAttachments(ctx, AttachmentListOptions{MessageID: "m1"})
+	require.NoError(t, err)
+	require.Empty(t, rows)
+
+	rows, err = s.ListAttachments(ctx, AttachmentListOptions{MessageID: "m2"})
+	require.NoError(t, err)
+	require.Len(t, rows, 1)
+	require.Equal(t, "a1", rows[0].AttachmentID)
+	require.Equal(t, "m2", rows[0].MessageID)
+	require.Equal(t, "c2", rows[0].ChannelID)
+	require.Equal(t, "attachments/aa/hash-file.png", rows[0].MediaPath)
+	require.Equal(t, "hash", rows[0].ContentSHA256)
+	require.Equal(t, int64(4), rows[0].ContentSize)
+	require.Equal(t, "fetched", rows[0].FetchStatus)
+}
+
 func seedAttachmentForGuild(ctx context.Context, s *Store, guildID, channelID, messageID, attachmentID string) error {
 	if err := s.UpsertGuild(ctx, GuildRecord{ID: guildID, Name: guildID, RawJSON: `{}`}); err != nil {
 		return err

internal/store/sqlc/queries.sql

@@ -382,7 +382,34 @@ insert into message_attachments(
 	attachment_id, message_id, guild_id, channel_id, author_id, filename,
 	content_type, size, url, proxy_url, text_content, media_path, content_sha256,
 	content_size, fetched_at, fetch_status, fetch_error, updated_at
-) values(?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?);
+) values(?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+on conflict(attachment_id) do update set
+	message_id = excluded.message_id,
+	guild_id = excluded.guild_id,
+	channel_id = excluded.channel_id,
+	author_id = excluded.author_id,
+	filename = excluded.filename,
+	content_type = excluded.content_type,
+	size = excluded.size,
+	url = excluded.url,
+	proxy_url = excluded.proxy_url,
+	text_content = excluded.text_content,
+	media_path = coalesce(excluded.media_path, message_attachments.media_path),
+	content_sha256 = coalesce(excluded.content_sha256, message_attachments.content_sha256),
+	content_size = case
+		when excluded.content_size > 0 then excluded.content_size
+		else message_attachments.content_size
+	end,
+	fetched_at = coalesce(excluded.fetched_at, message_attachments.fetched_at),
+	fetch_status = case
+		when excluded.fetch_status <> '' then excluded.fetch_status
+		else message_attachments.fetch_status
+	end,
+	fetch_error = case
+		when excluded.fetch_error <> '' then excluded.fetch_error
+		else message_attachments.fetch_error
+	end,
+	updated_at = excluded.updated_at;
 
 -- name: DeleteMentionEventsByMessage :exec
 delete from mention_events