show patch error as string not byte slice

staging/src/k8s.io/apiserver/pkg/endpoints/handlers/rest.go

@@ -565,11 +565,12 @@ func patchResource(
 	namespace := request.NamespaceValue(ctx)
 
 	var (
-		originalObjJS        []byte
-		originalPatchedObjJS []byte
-		originalObjMap       map[string]interface{}
-		originalPatchMap     map[string]interface{}
-		lastConflictErr      error
+		originalObjJS           []byte
+		originalPatchedObjJS    []byte
+		originalObjMap          map[string]interface{}
+		originalPatchMap        map[string]interface{}
+		lastConflictErr         error
+		originalResourceVersion string
 	)
 
 	// applyPatch is called every time GuaranteedUpdate asks for the updated object,
@@ -582,12 +583,18 @@ func patchResource(
 			return nil, errors.NewNotFound(resource.GroupResource(), name)
 		}
 
+		currentResourceVersion := ""
+		if currentMetadata, err := meta.Accessor(currentObject); err == nil {
+			currentResourceVersion = currentMetadata.GetResourceVersion()
+		}
+
 		switch {
 		case originalObjJS == nil && originalObjMap == nil:
 			// first time through,
 			// 1. apply the patch
 			// 2. save the original and patched to detect whether there were conflicting changes on retries
 
+			originalResourceVersion = currentResourceVersion
 			objToUpdate := patcher.New()
 
 			// For performance reasons, in case of strategicpatch, we avoid json
@@ -690,11 +697,12 @@ func patchResource(
 			if err != nil {
 				return nil, err
 			}
+
 			if hasConflicts {
 				diff1, _ := json.Marshal(currentPatchMap)
 				diff2, _ := json.Marshal(originalPatchMap)
-				patchDiffErr := fmt.Errorf("there is a meaningful conflict:\n diff1=%v\n, diff2=%v\n", diff1, diff2)
-				glog.V(4).Infof("patchResource failed for resource %s, because there is a meaningful conflict.\n diff1=%v\n, diff2=%v\n", name, diff1, diff2)
+				patchDiffErr := fmt.Errorf("there is a meaningful conflict (firstResourceVersion: %q, currentResourceVersion: %q):\n diff1=%v\n, diff2=%v\n", originalResourceVersion, currentResourceVersion, string(diff1), string(diff2))
+				glog.V(4).Infof("patchResource failed for resource %s, because there is a meaningful conflict(firstResourceVersion: %q, currentResourceVersion: %q):\n diff1=%v\n, diff2=%v\n", name, originalResourceVersion, currentResourceVersion, string(diff1), string(diff2))
 
 				// Return the last conflict error we got if we have one
 				if lastConflictErr != nil {

test/integration/client/client_test.go

@@ -268,14 +268,26 @@ func TestPatch(t *testing.T) {
 	pb := patchBodies[c.Core().RESTClient().APIVersion()]
 
 	execPatch := func(pt types.PatchType, body []byte) error {
-		return c.Core().RESTClient().Patch(pt).
+		result := c.Core().RESTClient().Patch(pt).
 			Resource(resource).
 			Namespace(ns.Name).
 			Name(name).
 			Body(body).
-			Do().
-			Error()
+			Do()
+		if result.Error() != nil {
+			return result.Error()
+		}
+
+		// trying to chase flakes, this should give us resource versions of objects as we step through
+		jsonObj, err := result.Raw()
+		if err != nil {
+			t.Log(err)
+		} else {
+			t.Logf("%v", string(jsonObj))
+		}
+		return nil
 	}
+
 	for k, v := range pb {
 		// add label
 		err := execPatch(k, v.AddLabelBody)