Make TracerProvider not allow to register a SpanProcessor after shutdown

CHANGELOG.md

@@ -33,6 +33,10 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Rename `Float64ObserverOption` to `Float64ObservableOption` in `go.opentelemetry.io/otel/metric/instrument`. (#3895)
 - The internal logging changes the verbosity level of info to `V(4)`, the verbosity level of debug to `V(8)`. (#3900)
 
+### Fixed
+
+- `TracerProvider` consistently doesn't allow to register a `SpanProcessor` after shutdown. (#3845)
+
 ### Removed
 
 - The deprecated `go.opentelemetry.io/otel/metric/global` package is removed. (#3829)

sdk/trace/provider.go

@@ -237,14 +237,13 @@ func (p *TracerProvider) ForceFlush(ctx context.Context) error {
 // Shutdown shuts down TracerProvider. All registered span processors are shut down
 // in the order they were registered and any held computational resources are released.
 func (p *TracerProvider) Shutdown(ctx context.Context) error {
-	spss := p.spanProcessors.Load().(spanProcessorStates)
-	if len(spss) == 0 {
-		return nil
-	}
-
 	p.mu.Lock()
 	defer p.mu.Unlock()
+	if p.isShutdown {
+		return nil
+	}
 	p.isShutdown = true
+	spss := p.spanProcessors.Load().(spanProcessorStates)
 
 	var retErr error
 	for _, sps := range spss {

sdk/trace/provider_test.go

@@ -50,6 +50,7 @@ func TestForceFlushAndShutdownTraceProviderWithoutProcessor(t *testing.T) {
 	stp := NewTracerProvider()
 	assert.NoError(t, stp.ForceFlush(context.Background()))
 	assert.NoError(t, stp.Shutdown(context.Background()))
+	assert.True(t, stp.isShutdown)
 }
 
 func TestShutdownTraceProvider(t *testing.T) {
@@ -60,6 +61,7 @@ func TestShutdownTraceProvider(t *testing.T) {
 	assert.NoError(t, stp.ForceFlush(context.Background()))
 	assert.True(t, sp.flushed, "error ForceFlush basicSpanProcessor")
 	assert.NoError(t, stp.Shutdown(context.Background()))
+	assert.True(t, stp.isShutdown)
 	assert.True(t, sp.closed, "error Shutdown basicSpanProcessor")
 }
 
@@ -74,6 +76,7 @@ func TestFailedProcessorShutdown(t *testing.T) {
 	err := stp.Shutdown(context.Background())
 	assert.Error(t, err)
 	assert.Equal(t, err, spErr)
+	assert.True(t, stp.isShutdown)
 }
 
 func TestFailedProcessorsShutdown(t *testing.T) {
@@ -94,6 +97,7 @@ func TestFailedProcessorsShutdown(t *testing.T) {
 	assert.EqualError(t, err, "basic span processor shutdown failure1; basic span processor shutdown failure2")
 	assert.True(t, sp1.closed)
 	assert.True(t, sp2.closed)
+	assert.True(t, stp.isShutdown)
 }
 
 func TestFailedProcessorShutdownInUnregister(t *testing.T) {
@@ -110,6 +114,7 @@ func TestFailedProcessorShutdownInUnregister(t *testing.T) {
 
 	err := stp.Shutdown(context.Background())
 	assert.NoError(t, err)
+	assert.True(t, stp.isShutdown)
 }
 
 func TestSchemaURL(t *testing.T) {
@@ -122,6 +127,32 @@ func TestSchemaURL(t *testing.T) {
 	assert.EqualValues(t, schemaURL, tracerStruct.instrumentationScope.SchemaURL)
 }
 
+func TestRegisterAfterShutdownWithoutProcessors(t *testing.T) {
+	stp := NewTracerProvider()
+	err := stp.Shutdown(context.Background())
+	assert.NoError(t, err)
+	assert.True(t, stp.isShutdown)
+
+	sp := &basicSpanProcessor{}
+	stp.RegisterSpanProcessor(sp) // no-op
+	assert.Empty(t, stp.spanProcessors.Load().(spanProcessorStates))
+}
+
+func TestRegisterAfterShutdownWithProcessors(t *testing.T) {
+	stp := NewTracerProvider()
+	sp1 := &basicSpanProcessor{}
+
+	stp.RegisterSpanProcessor(sp1)
+	err := stp.Shutdown(context.Background())
+	assert.NoError(t, err)
+	assert.True(t, stp.isShutdown)
+	assert.Empty(t, stp.spanProcessors.Load().(spanProcessorStates))
+
+	sp2 := &basicSpanProcessor{}
+	stp.RegisterSpanProcessor(sp2) // no-op
+	assert.Empty(t, stp.spanProcessors.Load().(spanProcessorStates))
+}
+
 func TestTracerProviderSamplerConfigFromEnv(t *testing.T) {
 	type testCase struct {
 		sampler             string