fix(vector): re-sync a note's vectors by replacing them; roll back a failed insert (#68)

The vectors table is a vec0 virtual table, where INSERT OR REPLACE does not replace, so syncing a note that already had vectors failed with a UNIQUE constraint error and the edit never reached the index. AddDocuments also shadowed err inside its loop, so a failed insert left the write transaction open and later writes failed with 'database is locked'.

Add Client.ReplaceDocuments (delete and insert in one transaction) and use it from SyncObservation and SyncSummary. The shared write function has a named result, so every failed return rolls back. Fixes #66.

Co-authored-by: Claude Sonnet 5.5 <[email protected]>

internal/vector/sqlitevec/sync_test.go

@@ -346,3 +346,57 @@ func TestSync_FormatObservationDocs_EmptyScope(t *testing.T) {
 	assert.Len(t, docs, 1)
 	assert.Equal(t, "project", docs[0].Metadata["scope"])
 }
+
+func vectorCount(t *testing.T, c *Client, where string, args ...any) int {
+	t.Helper()
+	var n int
+	require.NoError(t, c.db.QueryRow("SELECT COUNT(*) FROM vectors WHERE "+where, args...).Scan(&n))
+	return n
+}
+
+func TestSync_SyncObservation_AgainReplacesTheDocumentsOfTheNote(t *testing.T) {
+	client, cleanup := testClient(t)
+	defer cleanup()
+	sync := NewSync(client)
+	ctx := context.Background()
+
+	obs := &models.Observation{
+		ID: 7, SDKSessionID: "s", Project: "alpha", Type: models.ObsTypeDiscovery, Scope: models.ScopeGlobal,
+		Narrative: sql.NullString{String: "The queue keeps one consumer per tenant.", Valid: true},
+		Facts:     []string{"one consumer per tenant", "retries are capped", "dead letters go to a second queue"},
+	}
+	other := &models.Observation{
+		ID: 8, SDKSessionID: "s", Project: "alpha", Type: models.ObsTypeDiscovery, Scope: models.ScopeProject,
+		Narrative: sql.NullString{String: "Releases are cut on Thursdays.", Valid: true},
+	}
+	require.NoError(t, sync.SyncObservation(ctx, obs))
+	require.NoError(t, sync.SyncObservation(ctx, other))
+	require.Equal(t, 4, vectorCount(t, client, "doc_type = 'observation' AND sqlite_id = ?", 7))
+
+	// The note was edited: one fact fewer, and it is a project note now.
+	obs.Facts = obs.Facts[:2]
+	obs.Scope = models.ScopeProject
+	require.NoError(t, sync.SyncObservation(ctx, obs), "syncing a note that already has documents is not an error")
+
+	assert.Equal(t, 3, vectorCount(t, client, "doc_type = 'observation' AND sqlite_id = ?", 7), "narrative and two facts; the dropped fact's document is gone")
+	assert.Equal(t, 0, vectorCount(t, client, "doc_id = ?", "obs_7_fact_2"))
+	assert.Equal(t, 3, vectorCount(t, client, "sqlite_id = ? AND scope = 'project'", 7), "the new scope is what the vectors carry")
+	assert.Equal(t, 1, vectorCount(t, client, "sqlite_id = ?", 8), "other notes are not touched")
+}
+
+func TestSync_SyncSummary_AgainReplacesTheDocumentsOfTheSummary(t *testing.T) {
+	client, cleanup := testClient(t)
+	defer cleanup()
+	sync := NewSync(client)
+	ctx := context.Background()
+
+	summary := &models.SessionSummary{
+		ID: 3, SDKSessionID: "s", Project: "alpha",
+		Request: sql.NullString{String: "Add the queue", Valid: true}, Learned: sql.NullString{String: "One consumer per tenant", Valid: true},
+	}
+	require.NoError(t, sync.SyncSummary(ctx, summary))
+	summary.Learned = sql.NullString{}
+	require.NoError(t, sync.SyncSummary(ctx, summary))
+
+	assert.Equal(t, 1, vectorCount(t, client, "doc_type = 'session_summary' AND sqlite_id = ?", 3), "the field that was emptied has no document any more")
+}