sdk/trace: Fix goroutine leak in simpleSpanProcessor.Shutdown (#6368)

Side-effect when working towards
https://github.com/open-telemetry/opentelemetry-go/issues/6360

- Fix goroutine leaks from tests in places where batch processor was not
shut down
- Fix goroutine leak in simpleSpanProcessor.Shutdown

sdk/go.mod

@@ -11,6 +11,7 @@ require (
 	github.com/stretchr/testify v1.10.0
 	go.opentelemetry.io/otel v1.34.0
 	go.opentelemetry.io/otel/trace v1.34.0
+	go.uber.org/goleak v1.3.0
 	golang.org/x/sys v0.30.0
 )
 

sdk/go.sum

@@ -21,6 +21,8 @@ github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOf
 github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 go.opentelemetry.io/auto/sdk v1.1.0 h1:cH53jehLUN6UFLY71z+NDOiNJqDdPRaXzTel0sJySYA=
 go.opentelemetry.io/auto/sdk v1.1.0/go.mod h1:3wSPjt5PWp2RhlCcmmOial7AvC4DQqZb7a7wCow3W8A=
+go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
+go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
 golang.org/x/sys v0.30.0 h1:QjkSwP/36a20jFYWkSue1YwXzLmsV5Gfq7Eiy72C1uc=
 golang.org/x/sys v0.30.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=

sdk/trace/batch_span_processor_test.go

@@ -12,8 +12,6 @@ import (
 	"testing"
 	"time"
 
-	ottest "go.opentelemetry.io/otel/sdk/internal/internaltest"
-
 	"github.com/go-logr/logr"
 	"github.com/go-logr/logr/funcr"
 	"github.com/stretchr/testify/assert"
@@ -21,6 +19,7 @@ import (
 
 	"go.opentelemetry.io/otel/internal/global"
 	"go.opentelemetry.io/otel/sdk/internal/env"
+	ottest "go.opentelemetry.io/otel/sdk/internal/internaltest"
 	sdktrace "go.opentelemetry.io/otel/sdk/trace"
 	"go.opentelemetry.io/otel/sdk/trace/tracetest"
 	"go.opentelemetry.io/otel/trace"
@@ -544,6 +543,9 @@ func TestBatchSpanProcessorForceFlushCancellation(t *testing.T) {
 	cancel()
 
 	bsp := sdktrace.NewBatchSpanProcessor(indefiniteExporter{})
+	t.Cleanup(func() {
+		assert.NoError(t, bsp.Shutdown(context.Background()))
+	})
 	if got, want := bsp.ForceFlush(ctx), context.Canceled; !errors.Is(got, want) {
 		t.Errorf("expected %q error, got %v", want, got)
 	}
@@ -556,6 +558,9 @@ func TestBatchSpanProcessorForceFlushTimeout(t *testing.T) {
 	<-ctx.Done()
 
 	bsp := sdktrace.NewBatchSpanProcessor(indefiniteExporter{})
+	t.Cleanup(func() {
+		assert.NoError(t, bsp.Shutdown(context.Background()))
+	})
 	if got, want := bsp.ForceFlush(ctx), context.DeadlineExceeded; !errors.Is(got, want) {
 		t.Errorf("expected %q error, got %v", want, got)
 	}
@@ -569,6 +574,9 @@ func TestBatchSpanProcessorForceFlushQueuedSpans(t *testing.T) {
 	tp := sdktrace.NewTracerProvider(
 		sdktrace.WithBatcher(exp),
 	)
+	t.Cleanup(func() {
+		assert.NoError(t, tp.Shutdown(context.Background()))
+	})
 
 	tracer := tp.Tracer("tracer")
 
@@ -641,6 +649,9 @@ func BenchmarkSpanProcessorOnEnd(b *testing.B) {
 				tracetest.NewNoopExporter(),
 				sdktrace.WithMaxExportBatchSize(bb.batchSize),
 			)
+			b.Cleanup(func() {
+				_ = bsp.Shutdown(context.Background())
+			})
 			snap := tracetest.SpanStub{}.Snapshot()
 
 			b.ResetTimer()
@@ -665,6 +676,9 @@ func BenchmarkSpanProcessorVerboseLogging(b *testing.B) {
 			tracetest.NewNoopExporter(),
 			sdktrace.WithMaxExportBatchSize(10),
 		))
+	b.Cleanup(func() {
+		_ = tp.Shutdown(context.Background())
+	})
 	tracer := tp.Tracer("bench")
 	ctx := context.Background()
 

sdk/trace/main_test.go

@@ -0,0 +1,14 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package trace
+
+import (
+	"testing"
+
+	"go.uber.org/goleak"
+)
+
+func TestMain(m *testing.M) {
+	goleak.VerifyTestMain(m)
+}

sdk/trace/simple_span_processor.go

@@ -58,7 +58,7 @@ func (ssp *simpleSpanProcessor) Shutdown(ctx context.Context) error {
 	var err error
 	ssp.stopOnce.Do(func() {
 		stopFunc := func(exp SpanExporter) (<-chan error, func()) {
-			done := make(chan error)
+			done := make(chan error, 1)
 			return done, func() { done <- exp.Shutdown(ctx) }
 		}
 

sdk/trace/util_test.go

@@ -4,12 +4,18 @@
 package trace_test
 
 import (
+	"context"
 	"testing"
 
+	"github.com/stretchr/testify/assert"
+
 	sdktrace "go.opentelemetry.io/otel/sdk/trace"
 )
 
-func basicTracerProvider(_ *testing.T) *sdktrace.TracerProvider {
+func basicTracerProvider(t *testing.T) *sdktrace.TracerProvider {
 	tp := sdktrace.NewTracerProvider(sdktrace.WithSampler(sdktrace.AlwaysSample()))
+	t.Cleanup(func() {
+		assert.NoError(t, tp.Shutdown(context.Background()))
+	})
 	return tp
 }