add comments

Author: wxiaoguang

modules/gtprof/trace_test.go

@@ -55,17 +55,17 @@ func TestTraceStarter(t *testing.T) {
 		ctx, span := GetTracer().Start(ctx, "span1")
 		defer span.End()
 		func(ctx context.Context) {
-			ctx, span := GetTracer().Start(ctx, "spanA")
+			_, span := GetTracer().Start(ctx, "spanA")
 			defer span.End()
 		}(ctx)
 		func(ctx context.Context) {
-			ctx, span := GetTracer().Start(ctx, "spanB")
+			_, span := GetTracer().Start(ctx, "spanB")
 			defer span.End()
 		}(ctx)
 	}(ctx)
 
 	func(ctx context.Context) {
-		ctx, span := GetTracer().Start(ctx, "span2")
+		_, span := GetTracer().Start(ctx, "span2")
 		defer span.End()
 	}(ctx)
 
@@ -79,11 +79,11 @@ func TestTraceStarter(t *testing.T) {
 		}
 	}
 	collectSpanNames("", span.internalSpans[0].(*testTraceSpan).vendorSpan)
-	assert.Equal(t, []string([]string{
+	assert.Equal(t, []string{
 		"/root",
 		"/root/span1",
 		"/root/span1/spanA",
 		"/root/span1/spanB",
 		"/root/span2",
-	}), spanFullNames)
+	}, spanFullNames)
 }

modules/web/routing/context.go

@@ -15,6 +15,9 @@ type contextKeyType struct{}
 
 var contextKey contextKeyType
 
+// StartContextSpan starts a trace span in Gitea's web request context
+// Due to the design limitation of Gitea's web framework, it can't use `context.WithValue` to bind a new span into a new context.
+// So here we use our "reqctx" framework to achieve the same result: web request context could always see the latest "span".
 func StartContextSpan(ctx reqctx.RequestContext, spanName string) (*gtprof.TraceSpan, func()) {
 	curTraceSpan := gtprof.GetContextSpan(ctx)
 	_, newTraceSpan := gtprof.GetTracer().Start(ctx, spanName)