Fixed the review changes

stats/opentelemetry/e2e_test.go

@@ -885,6 +885,14 @@ func (s) TestMetricsAndTracesOptionEnabled(t *testing.T) {
 					Key:   "FailFast",
 					Value: attribute.BoolValue(false),
 				},
+				{
+					Key:   "previous-rpc-attempts",
+					Value: attribute.IntValue(0),
+				},
+				{
+					Key:   "transparent-retry",
+					Value: attribute.BoolValue(false),
+				},
 			},
 			events: []trace.Event{
 				{
@@ -999,6 +1007,14 @@ func (s) TestMetricsAndTracesOptionEnabled(t *testing.T) {
 					Key:   "FailFast",
 					Value: attribute.BoolValue(false),
 				},
+				{
+					Key:   "previous-rpc-attempts",
+					Value: attribute.IntValue(0),
+				},
+				{
+					Key:   "transparent-retry",
+					Value: attribute.BoolValue(false),
+				},
 			},
 			events: nil,
 		},
@@ -1093,6 +1109,14 @@ func (s) TestSpan(t *testing.T) {
 					Key:   "FailFast",
 					Value: attribute.BoolValue(false),
 				},
+				{
+					Key:   "previous-rpc-attempts",
+					Value: attribute.IntValue(0),
+				},
+				{
+					Key:   "transparent-retry",
+					Value: attribute.BoolValue(false),
+				},
 			},
 			events: []trace.Event{
 				{
@@ -1191,6 +1215,14 @@ func (s) TestSpan(t *testing.T) {
 					Key:   "FailFast",
 					Value: attribute.BoolValue(false),
 				},
+				{
+					Key:   "previous-rpc-attempts",
+					Value: attribute.IntValue(0),
+				},
+				{
+					Key:   "transparent-retry",
+					Value: attribute.BoolValue(false),
+				},
 			},
 			events: nil,
 		},
@@ -1287,6 +1319,14 @@ func (s) TestSpan_WithW3CContextPropagator(t *testing.T) {
 					Key:   "FailFast",
 					Value: attribute.BoolValue(false),
 				},
+				{
+					Key:   "previous-rpc-attempts",
+					Value: attribute.IntValue(0),
+				},
+				{
+					Key:   "transparent-retry",
+					Value: attribute.BoolValue(false),
+				},
 			},
 			events: []trace.Event{
 				{
@@ -1385,6 +1425,14 @@ func (s) TestSpan_WithW3CContextPropagator(t *testing.T) {
 					Key:   "FailFast",
 					Value: attribute.BoolValue(false),
 				},
+				{
+					Key:   "previous-rpc-attempts",
+					Value: attribute.IntValue(0),
+				},
+				{
+					Key:   "transparent-retry",
+					Value: attribute.BoolValue(false),
+				},
 			},
 			events: nil,
 		},
@@ -1554,6 +1602,8 @@ func (s) TestTraceSpan_WithRetriesAndNameResolutionDelay(t *testing.T) {
 						attributes: []attribute.KeyValue{
 							attribute.Bool("Client", false),
 							attribute.Bool("FailFast", false),
+							attribute.Int("previous-rpc-attempts", 0),
+							attribute.Bool("transparent-retry", false),
 						},
 						events: []trace.Event{
 							{
@@ -1593,6 +1643,8 @@ func (s) TestTraceSpan_WithRetriesAndNameResolutionDelay(t *testing.T) {
 						attributes: []attribute.KeyValue{
 							attribute.Bool("Client", false),
 							attribute.Bool("FailFast", false),
+							attribute.Int("previous-rpc-attempts", 0),
+							attribute.Bool("transparent-retry", false),
 						},
 						events: []trace.Event{
 							{
@@ -1632,6 +1684,8 @@ func (s) TestTraceSpan_WithRetriesAndNameResolutionDelay(t *testing.T) {
 						attributes: []attribute.KeyValue{
 							attribute.Bool("Client", false),
 							attribute.Bool("FailFast", false),
+							attribute.Int("previous-rpc-attempts", 0),
+							attribute.Bool("transparent-retry", false),
 						},
 						events: []trace.Event{
 							{
@@ -1685,6 +1739,8 @@ func (s) TestTraceSpan_WithRetriesAndNameResolutionDelay(t *testing.T) {
 						attributes: []attribute.KeyValue{
 							attribute.Bool("Client", false),
 							attribute.Bool("FailFast", false),
+							attribute.Int("previous-rpc-attempts", 0),
+							attribute.Bool("transparent-retry", false),
 						},
 						events: []trace.Event{
 							{
@@ -1766,6 +1822,8 @@ func (s) TestTraceSpan_WithRetriesAndNameResolutionDelay(t *testing.T) {
 						attributes: []attribute.KeyValue{
 							attribute.Bool("Client", false),
 							attribute.Bool("FailFast", false),
+							attribute.Int("previous-rpc-attempts", 0),
+							attribute.Bool("transparent-retry", false),
 						},
 						events: nil,
 					},
@@ -1797,6 +1855,8 @@ func (s) TestTraceSpan_WithRetriesAndNameResolutionDelay(t *testing.T) {
 						attributes: []attribute.KeyValue{
 							attribute.Bool("Client", false),
 							attribute.Bool("FailFast", false),
+							attribute.Int("previous-rpc-attempts", 0),
+							attribute.Bool("transparent-retry", false),
 						},
 						events: nil,
 					},
@@ -1828,6 +1888,8 @@ func (s) TestTraceSpan_WithRetriesAndNameResolutionDelay(t *testing.T) {
 						attributes: []attribute.KeyValue{
 							attribute.Bool("Client", false),
 							attribute.Bool("FailFast", false),
+							attribute.Int("previous-rpc-attempts", 0),
+							attribute.Bool("transparent-retry", false),
 						},
 						events: []trace.Event{
 							{
@@ -1867,6 +1929,8 @@ func (s) TestTraceSpan_WithRetriesAndNameResolutionDelay(t *testing.T) {
 						attributes: []attribute.KeyValue{
 							attribute.Bool("Client", false),
 							attribute.Bool("FailFast", false),
+							attribute.Int("previous-rpc-attempts", 0),
+							attribute.Bool("transparent-retry", false),
 						},
 						events: []trace.Event{
 							{
@@ -2028,6 +2092,8 @@ func (s) TestStreamingRPC_TraceSequenceNumbers(t *testing.T) {
 			attributes: []attribute.KeyValue{
 				attribute.Bool("Client", false),
 				attribute.Bool("FailFast", false),
+				attribute.Int("previous-rpc-attempts", 0),
+				attribute.Bool("transparent-retry", false),
 			},
 		},
 		{

stats/opentelemetry/trace.go

@@ -42,20 +42,26 @@ func populateSpan(rs stats.RPCStats, ai *attemptInfo) {
 		// Note: Go always added Client and FailFast attributes even though they are not
 		// defined by the OpenCensus gRPC spec. Thus, they are unimportant for
 		// correctness.
-		attrs := []attribute.KeyValue{
+		// previousRPCAttempts tracks the number of previous RPC attempts.
+		// If ai.previousRPCAttempts is nil (which can occur on the server path),
+		// prevAttempts defaults to 0 to avoid a nil pointer dereference.
+		previousRPCAttempts := int64(0)
+		if ai.previousRPCAttempts != nil {
+			previousRPCAttempts = int64(ai.previousRPCAttempts.Load())
+		}
+		span.SetAttributes(
 			attribute.Bool("Client", rs.Client),
 			attribute.Bool("FailFast", rs.FailFast),
-		}
+			// TODO: Remove "previous-rpc-attempts" and "transparent-retry"
-		if rs.Client {
+			// attributes from server spans. These attributes are only relevant
-			attrs = append(attrs,
+			// to client spans.
-				attribute.Int64("previous-rpc-attempts", int64(ai.previousRPCAttempts.Load())),
+			attribute.Int64("previous-rpc-attempts", previousRPCAttempts),
 			attribute.Bool("transparent-retry", rs.IsTransparentRetryAttempt),
 		)
-		}
-		span.SetAttributes(attrs...)
 		// Increment retry count for the next attempt if not a transparent
-		// retry.
+		// retry. Added nil check to avoid panic on server path where
-		if !rs.IsTransparentRetryAttempt && rs.Client {
+		// previousRPCAttempts is not set.
+		if !rs.IsTransparentRetryAttempt && ai.previousRPCAttempts != nil {
 			ai.previousRPCAttempts.Add(1)
 		}
 	case *stats.PickerUpdated: