tracing: remove (*Tracer).SetForceRealSpans

It was a testing crutch that is no longer necessary now that
we've moved off the opentracing interfaces.

Release note: None

pkg/util/log/ambient_context_test.go

@@ -16,6 +16,7 @@ import (
 
 	"github.com/cockroachdb/cockroach/pkg/util/tracing"
 	"github.com/cockroachdb/logtags"
+	"github.com/stretchr/testify/require"
 )
 
 func TestAnnotateCtxTags(t *testing.T) {
@@ -40,14 +41,13 @@ func TestAnnotateCtxTags(t *testing.T) {
 
 func TestAnnotateCtxSpan(t *testing.T) {
 	tracer := tracing.NewTracer()
-	tracer.SetForceRealSpans(true)
 
 	ac := AmbientContext{Tracer: tracer}
 	ac.AddLogTag("ambient", nil)
 
 	// Annotate a context that has an open span.
 
-	sp1 := tracer.StartSpan("root")
+	sp1 := tracer.StartRootSpan("root", nil /* logTags */, tracing.RecordableSpan)
 	sp1.StartRecording(tracing.SingleNodeRecording)
 	ctx1 := tracing.ContextWithSpan(context.Background(), sp1)
 	Event(ctx1, "a")
@@ -70,20 +70,15 @@ func TestAnnotateCtxSpan(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	// Annotate a context that has no span.
+	// Annotate a context that has no span. The tracer will create a non-recordable
+	// span. We just check here that AnnotateCtxWithSpan properly returns it to the
+	// caller.
 
 	ac.Tracer = tracer
 	ctx, sp := ac.AnnotateCtxWithSpan(context.Background(), "s")
-	sp.StartRecording(tracing.SingleNodeRecording)
-	Event(ctx, "a")
-	sp.Finish()
-	if err := tracing.TestingCheckRecordedSpans(sp.GetRecording(), `
-	  Span s:
-			tags: ambient=
-			event: [ambient] a
-	`); err != nil {
-		t.Fatal(err)
-	}
+	require.Equal(t, sp, tracing.SpanFromContext(ctx))
+	require.NotNil(t, sp)
+	require.True(t, sp.IsBlackHole())
 }
 
 func TestAnnotateCtxNodeStoreReplica(t *testing.T) {

pkg/util/log/trace_test.go

@@ -65,8 +65,7 @@ func TestTrace(t *testing.T) {
 	Event(ctx, "should-not-show-up")
 
 	tracer := tracing.NewTracer()
-	tracer.SetForceRealSpans(true)
-	sp := tracer.StartSpan("s")
+	sp := tracer.StartRootSpan("s", nil /* logTags */, tracing.RecordableSpan)
 	sp.StartRecording(tracing.SingleNodeRecording)
 	ctxWithSpan := tracing.ContextWithSpan(ctx, sp)
 	Event(ctxWithSpan, "test1")
@@ -95,8 +94,7 @@ func TestTraceWithTags(t *testing.T) {
 	ctx = logtags.AddTag(ctx, "tag", 1)
 
 	tracer := tracing.NewTracer()
-	tracer.SetForceRealSpans(true)
-	sp := tracer.StartSpan("s")
+	sp := tracer.StartRootSpan("s", nil /* logTags */, tracing.RecordableSpan)
 	ctxWithSpan := tracing.ContextWithSpan(ctx, sp)
 	sp.StartRecording(tracing.SingleNodeRecording)
 
@@ -182,8 +180,7 @@ func TestEventLogAndTrace(t *testing.T) {
 	VErrEvent(ctxWithEventLog, noLogV(), "testerr")
 
 	tracer := tracing.NewTracer()
-	tracer.SetForceRealSpans(true)
-	sp := tracer.StartSpan("s")
+	sp := tracer.StartRootSpan("s", nil /* logTags */, tracing.RecordableSpan)
 	sp.StartRecording(tracing.SingleNodeRecording)
 	ctxWithBoth := tracing.ContextWithSpan(ctxWithEventLog, sp)
 	// Events should only go to the trace.

pkg/util/tracing/tracer.go

@@ -88,12 +88,6 @@ type Tracer struct {
 	// x/net/trace or lightstep and we are not recording.
 	noopSpan *Span
 
-	// If forceRealSpans is set, this Tracer will always create real spans (never
-	// noopSpans), regardless of the recording or lightstep configuration. Used
-	// by tests for situations when they need to indirectly create spans and don't
-	// have the option of passing the Recordable option to their constructor.
-	forceRealSpans bool
-
 	// True if tracing to the debug/requests endpoint. Accessed via t.useNetTrace().
 	_useNetTrace int32 // updated atomically
 
@@ -145,14 +139,6 @@ func (t *Tracer) Close() {
 	t.setShadowTracer(nil, nil)
 }
 
-// SetForceRealSpans sets forceRealSpans option to v and returns the previous
-// value.
-func (t *Tracer) SetForceRealSpans(v bool) bool {
-	prevVal := t.forceRealSpans
-	t.forceRealSpans = v
-	return prevVal
-}
-
 func (t *Tracer) setShadowTracer(manager shadowTracerManager, tr opentracing.Tracer) {
 	var shadow *shadowTracer
 	if manager != nil {
@@ -270,7 +256,7 @@ const (
 // context.
 func (t *Tracer) AlwaysTrace() bool {
 	shadowTracer := t.getShadowTracer()
-	return t.useNetTrace() || shadowTracer != nil || t.forceRealSpans
+	return t.useNetTrace() || shadowTracer != nil
 }
 
 // StartRootSpan creates a root Span. This is functionally equivalent to: