Remove resampling on span.SetName

CHANGELOG.md

@@ -18,6 +18,10 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Added `resource.Default()` for use with meter and tracer providers. (#1507)
 - Added `Keys()` method to `propagation.TextMapCarrier` and `propagation.HeaderCarrier` to adapt `http.Header` to this interface. (#1544)
 
+### Removed
+
+- Removed attempt to resample spans upon changing the span name with `span.SetName()`. (#1545)
+
 ## [0.17.0] - 2020-02-12
 
 ### Changed

sdk/trace/span.go

@@ -302,35 +302,7 @@ func (s *span) SetName(name string) {
 
 	s.mu.Lock()
 	defer s.mu.Unlock()
-
 	s.name = name
-	// SAMPLING
-	noParent := !s.parent.SpanID.IsValid()
-	var ctx trace.SpanContext
-	if noParent {
-		ctx = trace.SpanContext{}
-	} else {
-		// FIXME: Where do we get the parent context from?
-		ctx = s.spanContext
-	}
-	data := samplingData{
-		noParent:     noParent,
-		remoteParent: s.hasRemoteParent,
-		parent:       ctx,
-		name:         name,
-		cfg:          s.tracer.provider.config.Load().(*Config),
-		span:         s,
-		attributes:   s.attributes.toKeyValue(),
-		links:        s.interfaceArrayToLinksArray(),
-		kind:         s.spanKind,
-	}
-	sampled := makeSamplingDecision(data)
-
-	// Adding attributes directly rather than using s.SetAttributes()
-	// as s.mu is already locked and attempting to do so would deadlock.
-	for _, a := range sampled.Attributes {
-		s.attributes.add(a)
-	}
 }
 
 // Name returns the name of this span.

sdk/trace/trace_test.go

@@ -158,58 +158,47 @@ func (ts testSampler) Description() string {
 }
 
 func TestSetName(t *testing.T) {
-	fooSampler := &testSampler{prefix: "foo", t: t}
-	tp := NewTracerProvider(WithConfig(Config{DefaultSampler: fooSampler}))
+	tp := NewTracerProvider()
 
 	type testCase struct {
-		name          string
-		newName       string
-		sampledBefore bool
-		sampledAfter  bool
+		name    string
+		newName string
 	}
 	for idx, tt := range []testCase{
 		{ // 0
-			name:          "foobar",
-			newName:       "foobaz",
-			sampledBefore: true,
-			sampledAfter:  true,
+			name:    "foobar",
+			newName: "foobaz",
 		},
 		{ // 1
-			name:          "foobar",
-			newName:       "barbaz",
-			sampledBefore: true,
-			sampledAfter:  false,
+			name:    "foobar",
+			newName: "barbaz",
 		},
 		{ // 2
-			name:          "barbar",
-			newName:       "barbaz",
-			sampledBefore: false,
-			sampledAfter:  false,
+			name:    "barbar",
+			newName: "barbaz",
 		},
 		{ // 3
-			name:          "barbar",
-			newName:       "foobar",
-			sampledBefore: false,
-			sampledAfter:  true,
+			name:    "barbar",
+			newName: "foobar",
 		},
 	} {
-		span := startNamedSpan(tp, "SetName", tt.name)
-		if fooSampler.callCount == 0 {
-			t.Errorf("%d: the sampler was not even called during span creation", idx)
-		}
-		fooSampler.callCount = 0
-		if gotSampledBefore := span.SpanContext().IsSampled(); tt.sampledBefore != gotSampledBefore {
-			t.Errorf("%d: invalid sampling decision before rename, expected %v, got %v", idx, tt.sampledBefore, gotSampledBefore)
-		}
-		span.SetName(tt.newName)
-		if fooSampler.callCount == 0 {
-			t.Errorf("%d: the sampler was not even called during span rename", idx)
+		sp := startNamedSpan(tp, "SetName", tt.name)
+		if sdkspan, ok := sp.(*span); ok {
+			if sdkspan.Name() != tt.name {
+				t.Errorf("%d: invalid name at span creation, expected %v, got %v", idx, tt.name, sdkspan.Name())
+			}
+		} else {
+			t.Errorf("%d: unable to coerce span to SDK span, is type %T", idx, sp)
 		}
-		fooSampler.callCount = 0
-		if gotSampledAfter := span.SpanContext().IsSampled(); tt.sampledAfter != gotSampledAfter {
-			t.Errorf("%d: invalid sampling decision after rename, expected %v, got %v", idx, tt.sampledAfter, gotSampledAfter)
+		sp.SetName(tt.newName)
+		if sdkspan, ok := sp.(*span); ok {
+			if sdkspan.Name() != tt.newName {
+				t.Errorf("%d: span name not changed, expected %v, got %v", idx, tt.newName, sdkspan.Name())
+			}
+		} else {
+			t.Errorf("%d: unable to coerce span to SDK span, is type %T", idx, sp)
 		}
-		span.End()
+		sp.End()
 	}
 }