return as no-op if repo name/url is identical

Signed-off-by: Matthew Fisher <matt.fisher@microsoft.com>

cmd/helm/repo_add.go

@@ -116,6 +116,15 @@ func (o *repoAddOptions) run(out io.Writer) error {
 		return err
 	}
 
+	// If the same name and url already exists, return as a no-op.
+	// fixes https://github.com/helm/helm/issues/8771
+	if f.Has(o.name) {
+		e := f.Get(o.name)
+		if e.URL == o.url {
+			return nil
+		}
+	}
+
 	// If the repo exists and --force-update was not specified, error out.
 	if !o.forceUpdate && f.Has(o.name) {
 		return errors.Errorf("repository name (%s) already exists, please specify a different name", o.name)

cmd/helm/repo_add_test.go

@@ -77,6 +77,12 @@ func TestRepoAdd(t *testing.T) {
 		t.Error(err)
 	}
 
+	// try adding the same name and url again; should be a no-op and return
+	// successful.
+	if err := o.run(ioutil.Discard); err != nil {
+		t.Error(err)
+	}
+
 	f, err := repo.LoadFile(repoFile)
 	if err != nil {
 		t.Fatal(err)