Fix gogit GetRefCommitID (#32705) (#32712)

Backport #32705 by @Zettat123

Fix #32335

When we call `GetRefCommitID` and the reference is already a commit ID,
the `GetRefCommitID` with go-git will return a `NotExist` error. This PR
improves the `GetRefCommitID` for go-git. If the input is already a
commit ID, it will be returned directly.

Co-authored-by: Zettat123 <zettat123@gmail.com>

modules/git/repo_commit_gogit.go

@@ -14,9 +14,16 @@ import (
 	"github.com/go-git/go-git/v5/plumbing/object"
 )
 
-// GetRefCommitID returns the last commit ID string of given reference (branch or tag).
+// GetRefCommitID returns the last commit ID string of given reference.
 func (repo *Repository) GetRefCommitID(name string) (string, error) {
-	ref, err := repo.gogitRepo.Reference(plumbing.ReferenceName(name), true)
+	if plumbing.IsHash(name) {
+		return name, nil
+	}
+	refName := plumbing.ReferenceName(name)
+	if err := refName.Validate(); err != nil {
+		return "", err
+	}
+	ref, err := repo.gogitRepo.Reference(refName, true)
 	if err != nil {
 		if err == plumbing.ErrReferenceNotFound {
 			return "", ErrNotExist{

modules/git/repo_commit_test.go

@@ -101,3 +101,28 @@ func TestRepository_CommitsBetweenIDs(t *testing.T) {
 		assert.Len(t, commits, c.ExpectedCommits, "case %d", i)
 	}
 }
+
+func TestGetRefCommitID(t *testing.T) {
+	bareRepo1Path := filepath.Join(testReposDir, "repo1_bare")
+	bareRepo1, err := openRepositoryWithDefaultContext(bareRepo1Path)
+	assert.NoError(t, err)
+	defer bareRepo1.Close()
+
+	// these test case are specific to the repo1_bare test repo
+	testCases := []struct {
+		Ref              string
+		ExpectedCommitID string
+	}{
+		{RefNameFromBranch("master").String(), "ce064814f4a0d337b333e646ece456cd39fab612"},
+		{RefNameFromBranch("branch1").String(), "2839944139e0de9737a044f78b0e4b40d989a9e3"},
+		{RefNameFromTag("test").String(), "3ad28a9149a2864384548f3d17ed7f38014c9e8a"},
+		{"ce064814f4a0d337b333e646ece456cd39fab612", "ce064814f4a0d337b333e646ece456cd39fab612"},
+	}
+
+	for _, testCase := range testCases {
+		commitID, err := bareRepo1.GetRefCommitID(testCase.Ref)
+		if assert.NoError(t, err) {
+			assert.Equal(t, testCase.ExpectedCommitID, commitID)
+		}
+	}
+}