Fix fastforward git user configuration

pkg/fastforward/fastforward.go

@@ -203,6 +203,11 @@ func (f *FastForward) Run() (err error) {
 	}
 	logrus.Infof("Latest release branch revision is %s", releaseRev)
 
+	logrus.Info("Configuring git user and email")
+	if err := f.ConfigureGlobalDefaultUserAndEmail(); err != nil {
+		return errors.Wrap(err, "configure git user and email")
+	}
+
 	logrus.Info("Merging main branch changes into release branch")
 	if err := f.RepoMerge(repo, f.options.MainRef); err != nil {
 		return errors.Wrap(err, "merge main ref")

pkg/fastforward/fastforward_test.go

@@ -275,6 +275,17 @@ func TestRun(t *testing.T) {
 				require.NotNil(t, err)
 			},
 		},
+		{ // failure on ConfigureGlobalDefaultUserAndEmail
+			prepare: func(mock *fastforwardfakes.FakeImpl) *Options {
+				mock.IsReleaseBranchReturns(true)
+				mock.RepoHasRemoteBranchReturns(true, nil)
+				mock.ConfigureGlobalDefaultUserAndEmailReturns(errTest)
+				return &Options{Branch: branch}
+			},
+			assert: func(err error) {
+				require.NotNil(t, err)
+			},
+		},
 		{ // failure on RepoMergeBase
 			prepare: func(mock *fastforwardfakes.FakeImpl) *Options {
 				mock.IsReleaseBranchReturns(true)

pkg/fastforward/impl.go

@@ -57,6 +57,7 @@ type impl interface {
 	RemoveAll(string) error
 	MkdirTemp(string, string) (string, error)
 	Exists(string) bool
+	ConfigureGlobalDefaultUserAndEmail() error
 }
 
 func (*defaultImpl) CloneOrOpenDefaultGitHubRepoSSH(repo string) (*git.Repo, error) {
@@ -158,3 +159,7 @@ func (*defaultImpl) MkdirTemp(dir, pattern string) (string, error) {
 func (*defaultImpl) Exists(path string) bool {
 	return util.Exists(path)
 }
+
+func (*defaultImpl) ConfigureGlobalDefaultUserAndEmail() error {
+	return git.ConfigureGlobalDefaultUserAndEmail()
+}