Fix IDGenerator may generate zero TraceId / SpanId

CHANGELOG.md

@@ -30,6 +30,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ### Fixed
 
+- Retry trace and span ID generation if it generated an invalid one in `go.opentelemetry.io/otel/sdk/trace`. (#5514)
 - Log a warning to the OpenTelemetry internal logger when a `Record` in `go.opentelemetry.io/otel/sdk/log` drops an attribute due to a limit being reached. (#5376)
 - Identify the `Tracer` returned from the global `TracerProvider` in `go.opentelemetry.io/otel/global` with its schema URL. (#5426)
 - Identify the `Meter` returned from the global `MeterProvider` in `go.opentelemetry.io/otel/global` with its schema URL. (#5426)

sdk/trace/id_generator.go

@@ -41,8 +41,12 @@ func (gen *randomIDGenerator) NewSpanID(ctx context.Context, traceID trace.Trace
 	gen.Lock()
 	defer gen.Unlock()
 	sid := trace.SpanID{}
-	_, _ = gen.randSource.Read(sid[:])
-	return sid
+	for {
+		_, _ = gen.randSource.Read(sid[:])
+		if sid.IsValid() {
+			return sid
+		}
+	}
 }
 
 // NewIDs returns a non-zero trace ID and a non-zero span ID from a
@@ -51,9 +55,19 @@ func (gen *randomIDGenerator) NewIDs(ctx context.Context) (trace.TraceID, trace.
 	gen.Lock()
 	defer gen.Unlock()
 	tid := trace.TraceID{}
-	_, _ = gen.randSource.Read(tid[:])
 	sid := trace.SpanID{}
-	_, _ = gen.randSource.Read(sid[:])
+	for {
+		_, _ = gen.randSource.Read(tid[:])
+		if tid.IsValid() {
+			break
+		}
+	}
+	for {
+		_, _ = gen.randSource.Read(sid[:])
+		if sid.IsValid() {
+			break
+		}
+	}
 	return tid, sid
 }