contrib/gin-gonic/gin: join errors instead of using Last()

Author: theo303

contrib/gin-gonic/gin/gintrace.go

@@ -7,6 +7,7 @@
 package gin // import "github.com/DataDog/dd-trace-go/contrib/gin-gonic/gin/v2"
 
 import (
+	"errors"
 	"fmt"
 	"math"
 
@@ -54,8 +55,11 @@ func Middleware(service string, opts ...Option) gin.HandlerFunc {
 		span, ctx, finishSpans := httptrace.StartRequestSpan(c.Request, opts...)
 		defer func() {
 			status := c.Writer.Status()
-			err := c.Errors.Last()
-			if err != nil && cfg.propagateError && cfg.isStatusError(status) {
+			if cfg.propagateError && cfg.isStatusError(status) {
+				var err error
+				for _, e := range c.Errors {
+					err = errors.Join(err, e.Err)
+				}
 				finishSpans(status, cfg.isStatusError, tracer.WithError(err))
 			}
 			finishSpans(status, cfg.isStatusError)

contrib/gin-gonic/gin/gintrace_test.go

@@ -216,6 +216,41 @@ func TestError(t *testing.T) {
 		assert.Equal(componentName, span.Integration())
 	})
 
+	t.Run("server error - with error propagation - nil Errors in gin context", func(*testing.T) {
+		defer mt.Reset()
+
+		router := gin.New()
+		router.Use(Middleware("foobar", WithErrorPropagation()))
+
+		// configure a handler that returns an error and 5xx status code
+		router.GET("/server_err", func(c *gin.Context) {
+			c.AbortWithStatus(500)
+		})
+		r := httptest.NewRequest("GET", "/server_err", nil)
+		w := httptest.NewRecorder()
+		router.ServeHTTP(w, r)
+		response := w.Result()
+		defer response.Body.Close()
+		assert.Equal(response.StatusCode, 500)
+
+		// verify the errors and status are correct
+		spans := mt.FinishedSpans()
+		assert.Len(spans, 1)
+		if len(spans) < 1 {
+			t.Fatalf("no spans")
+		}
+		span := spans[0]
+		assert.Equal("http.request", span.OperationName())
+		assert.Equal("foobar", span.Tag(ext.ServiceName))
+		assert.Equal("500", span.Tag(ext.HTTPCode))
+		assert.Empty(span.Tag("gin.errors"))
+		// server errors set the ext.ErrorMsg tag
+		assert.Equal("500: Internal Server Error", span.Tag(ext.ErrorMsg))
+		assert.Equal(ext.SpanKindServer, span.Tag(ext.SpanKind))
+		assert.Equal("gin-gonic/gin", span.Tag(ext.Component))
+		assert.Equal(componentName, span.Integration())
+	})
+
 	t.Run("server error - without error propagation", func(*testing.T) {
 		defer mt.Reset()
 

contrib/gin-gonic/gin/option.go

@@ -95,7 +95,8 @@ func isServerError(statusCode int) bool {
 	return statusCode >= 500 && statusCode < 600
 }
 
-// WithErrorPropagation enables the propagation of gin's error to the span.
+// WithErrorPropagation enables the propagation of gin's errors to the span.
+// If there are multiple errors in the gin context, they will be all added to the span.
 func WithErrorPropagation() OptionFn {
 	return func(cfg *config) {
 		cfg.propagateError = true