agentdrain: remove duplicate NewClusterCreated field from AnomalyReport (#30938)

Author: Copilot

pkg/agentdrain/README.md

@@ -88,12 +88,11 @@ Describes anomalies detected for a log line.
 
 ```go
 type AnomalyReport struct {
-    IsNewTemplate     bool    // Line created a new cluster
-    LowSimilarity     bool    // Best match score was below SimThreshold
-    RareCluster       bool    // Matched cluster has been seen ≤ RareClusterThreshold times
-    NewClusterCreated bool    // This event produced a brand-new cluster
-    AnomalyScore      float64 // Weighted composite score in [0, 1]
-    Reason            string  // Human-readable anomaly description
+    IsNewTemplate bool    // Line produced a brand-new log cluster
+    LowSimilarity bool    // Best match score was below SimThreshold
+    RareCluster   bool    // Matched cluster has been seen ≤ RareClusterThreshold times
+    AnomalyScore  float64 // Weighted composite score in [0, 1]
+    Reason        string  // Human-readable anomaly description
 }
 ```
 

pkg/agentdrain/anomaly.go

@@ -36,8 +36,7 @@ func NewAnomalyDetector(simThreshold float64, rareClusterThreshold int) (*Anomal
 //   - cluster is the cluster that was matched or created.
 func (d *AnomalyDetector) Analyze(result *MatchResult, isNew bool, cluster *Cluster) *AnomalyReport {
 	report := &AnomalyReport{
-		IsNewTemplate:     isNew,
-		NewClusterCreated: isNew,
+		IsNewTemplate: isNew,
 		// LowSimilarity is mutually exclusive with IsNewTemplate: brand-new templates are
 		// already classified as anomalies, so we only evaluate similarity for existing ones.
 		LowSimilarity: !isNew && result.Similarity < d.threshold,

pkg/agentdrain/anomaly_test.go

@@ -18,14 +18,13 @@ func TestAnomalyDetector_Analyze(t *testing.T) {
 		isNew             bool
 		cluster           *Cluster
 		wantIsNewTemplate bool
-		wantNewCluster    bool
 		wantLowSimilarity bool
 		wantRareCluster   bool
 		wantScore         float64
 		wantReason        string
 	}{
 		{
-			// isNew=true → both IsNewTemplate and NewClusterCreated; size=1 ≤ rareThreshold=2 → RareCluster.
+			// isNew=true → IsNewTemplate; size=1 ≤ rareThreshold=2 → RareCluster.
 			// score = (1.0 + 0.3) / 2.0 = 0.65
 			name:              "new template creates cluster and is also rare",
 			simThreshold:      0.4,
@@ -34,7 +33,6 @@ func TestAnomalyDetector_Analyze(t *testing.T) {
 			isNew:             true,
 			cluster:           &Cluster{ID: 1, Template: []string{"stage=plan"}, Size: 1},
 			wantIsNewTemplate: true,
-			wantNewCluster:    true,
 			wantLowSimilarity: false,
 			wantRareCluster:   true,
 			wantScore:         0.65,
@@ -50,7 +48,6 @@ func TestAnomalyDetector_Analyze(t *testing.T) {
 			isNew:             false,
 			cluster:           &Cluster{ID: 1, Template: []string{"a", "b", "c"}, Size: 5},
 			wantIsNewTemplate: false,
-			wantNewCluster:    false,
 			wantLowSimilarity: true,
 			wantRareCluster:   false,
 			wantScore:         0.35,
@@ -66,7 +63,6 @@ func TestAnomalyDetector_Analyze(t *testing.T) {
 			isNew:             false,
 			cluster:           &Cluster{ID: 1, Template: []string{"a"}, Size: 1},
 			wantIsNewTemplate: false,
-			wantNewCluster:    false,
 			wantLowSimilarity: false,
 			wantRareCluster:   true,
 			wantScore:         0.15,
@@ -81,7 +77,6 @@ func TestAnomalyDetector_Analyze(t *testing.T) {
 			isNew:             false,
 			cluster:           &Cluster{ID: 1, Template: []string{"a", "b"}, Size: 100},
 			wantIsNewTemplate: false,
-			wantNewCluster:    false,
 			wantLowSimilarity: false,
 			wantRareCluster:   false,
 			wantScore:         0.0,
@@ -96,7 +91,6 @@ func TestAnomalyDetector_Analyze(t *testing.T) {
 			isNew:             false,
 			cluster:           &Cluster{ID: 1, Template: []string{"a"}, Size: 5},
 			wantIsNewTemplate: false,
-			wantNewCluster:    false,
 			wantLowSimilarity: false,
 			wantRareCluster:   false,
 			wantScore:         0.0,
@@ -112,7 +106,6 @@ func TestAnomalyDetector_Analyze(t *testing.T) {
 			isNew:             false,
 			cluster:           &Cluster{ID: 1, Template: []string{"a"}, Size: 5},
 			wantIsNewTemplate: false,
-			wantNewCluster:    false,
 			wantLowSimilarity: true,
 			wantRareCluster:   false,
 			wantScore:         0.35,
@@ -128,7 +121,6 @@ func TestAnomalyDetector_Analyze(t *testing.T) {
 			isNew:             false,
 			cluster:           &Cluster{ID: 1, Template: []string{"a"}, Size: 1},
 			wantIsNewTemplate: false,
-			wantNewCluster:    false,
 			wantLowSimilarity: true,
 			wantRareCluster:   true,
 			wantScore:         0.5,
@@ -143,7 +135,6 @@ func TestAnomalyDetector_Analyze(t *testing.T) {
 			isNew:             false,
 			cluster:           nil,
 			wantIsNewTemplate: false,
-			wantNewCluster:    false,
 			wantLowSimilarity: false,
 			wantRareCluster:   false,
 			wantScore:         0.0,
@@ -159,7 +150,6 @@ func TestAnomalyDetector_Analyze(t *testing.T) {
 			isNew:             true,
 			cluster:           &Cluster{ID: 1, Template: []string{"a"}, Size: 5},
 			wantIsNewTemplate: true,
-			wantNewCluster:    true,
 			wantLowSimilarity: false,
 			wantRareCluster:   true,
 			wantScore:         0.65,
@@ -177,7 +167,6 @@ func TestAnomalyDetector_Analyze(t *testing.T) {
 
 			require.NotNil(t, report, "Analyze should always return a non-nil report")
 			assert.Equal(t, tt.wantIsNewTemplate, report.IsNewTemplate, "IsNewTemplate mismatch")
-			assert.Equal(t, tt.wantNewCluster, report.NewClusterCreated, "NewClusterCreated mismatch")
 			assert.Equal(t, tt.wantLowSimilarity, report.LowSimilarity, "LowSimilarity mismatch")
 			assert.Equal(t, tt.wantRareCluster, report.RareCluster, "RareCluster mismatch")
 			assert.InDelta(t, tt.wantScore, report.AnomalyScore, 1e-9, "AnomalyScore mismatch")
@@ -342,28 +331,24 @@ func TestAnalyzeEvent(t *testing.T) {
 		name             string
 		event            AgentEvent
 		wantIsNew        bool
-		wantNewCluster   bool
 		errorDescription string
 	}{
 		{
 			name:             "first occurrence is flagged as new template",
 			event:            evtPlan,
 			wantIsNew:        true,
-			wantNewCluster:   true,
 			errorDescription: "first event",
 		},
 		{
 			name:             "second identical occurrence is not flagged as new",
 			event:            evtPlan,
 			wantIsNew:        false,
-			wantNewCluster:   false,
 			errorDescription: "second identical event",
 		},
 		{
 			name:             "distinct event creates its own new template",
 			event:            evtFinish,
 			wantIsNew:        true,
-			wantNewCluster:   true,
 			errorDescription: "distinct event",
 		},
 	}
@@ -375,7 +360,6 @@ func TestAnalyzeEvent(t *testing.T) {
 			require.NotNil(t, result, "AnalyzeEvent should return a non-nil result")
 			require.NotNil(t, report, "AnalyzeEvent should return a non-nil report")
 			assert.Equal(t, tt.wantIsNew, report.IsNewTemplate, "IsNewTemplate mismatch")
-			assert.Equal(t, tt.wantNewCluster, report.NewClusterCreated, "NewClusterCreated mismatch")
 		})
 	}
 }

pkg/agentdrain/spec_test.go

@@ -425,7 +425,7 @@ func TestSpec_Types_MatchResult(t *testing.T) {
 }
 
 // TestSpec_Types_AnomalyReport validates the documented AnomalyReport type structure.
-// Spec: IsNewTemplate, LowSimilarity, RareCluster, NewClusterCreated, AnomalyScore in [0,1], Reason.
+// Spec: IsNewTemplate, LowSimilarity, RareCluster, AnomalyScore in [0,1], Reason.
 func TestSpec_Types_AnomalyReport(t *testing.T) {
 	cfg := agentdrain.DefaultConfig()
 	miner, err := agentdrain.NewMiner(cfg)
@@ -439,7 +439,6 @@ func TestSpec_Types_AnomalyReport(t *testing.T) {
 	_ = report.IsNewTemplate
 	_ = report.LowSimilarity
 	_ = report.RareCluster
-	_ = report.NewClusterCreated
 	_ = report.Reason
 	assert.GreaterOrEqual(t, report.AnomalyScore, 0.0, "AnomalyReport.AnomalyScore should be in documented range [0, 1]")
 	assert.LessOrEqual(t, report.AnomalyScore, 1.0, "AnomalyReport.AnomalyScore should be in documented range [0, 1]")

pkg/agentdrain/types.go

@@ -56,14 +56,12 @@ type MatchResult struct {
 
 // AnomalyReport describes anomalies detected for a log line.
 type AnomalyReport struct {
-	// IsNewTemplate is true when the log line created a new cluster.
+	// IsNewTemplate is true when the log line produced a brand-new log cluster.
 	IsNewTemplate bool
 	// LowSimilarity is true when the best match score was below the configured threshold.
 	LowSimilarity bool
 	// RareCluster is true when the matched cluster has been seen fewer times than the rare threshold.
 	RareCluster bool
-	// NewClusterCreated is true when this event produced a brand-new cluster.
-	NewClusterCreated bool
 	// AnomalyScore is a weighted composite score in the range [0, 1].
 	AnomalyScore float64
 	// Reason is a human-readable description of all anomalies that were detected.