fix: detect renames when using diff-tree (#11038)

Regression of forgejo/forgejo!9587

`git-diff` will always find renames because it is implied by the `diff.renames` configuration option. Specify `--find-renames` to detect renames again.

Resolves forgejo/forgejo#11032

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/11038
Reviewed-by: Beowulf <beowulf@beocode.eu>
Co-authored-by: Gusted <postmaster@gusted.xyz>
Co-committed-by: Gusted <postmaster@gusted.xyz>

modules/git/repo_compare.go

@@ -189,7 +189,7 @@ var (
 // `useMergebase` is specified then the merge base between `base` and `head` is
 // used to compare against `head`.
 func (repo *Repository) GetShortStat(base, head string, useMergebase bool) (numFiles, totalAdditions, totalDeletions int, err error) {
-	cmd := NewCommand(repo.Ctx, "diff-tree", "--shortstat")
+	cmd := NewCommand(repo.Ctx, "diff-tree", "--shortstat", "--find-renames")
 	if useMergebase {
 		cmd = cmd.AddArguments("--merge-base")
 	}
@@ -211,7 +211,7 @@ func (repo *Repository) GetShortStat(base, head string, useMergebase bool) (numF
 
 // GetCommitShortStat returns the number of files, total additions and total deletions the commit has.
 func (repo *Repository) GetCommitShortStat(commitID string) (numFiles, totalAdditions, totalDeletions int, err error) {
-	cmd := NewCommand(repo.Ctx, "diff-tree", "--shortstat", "--no-commit-id", "--root").AddDynamicArguments(commitID)
+	cmd := NewCommand(repo.Ctx, "diff-tree", "--shortstat", "--no-commit-id", "--root", "--find-renames").AddDynamicArguments(commitID)
 	stdout, _, err := cmd.RunStdString(&RunOpts{Dir: repo.Path})
 	if err != nil {
 		return 0, 0, 0, err

modules/git/repo_compare_test.go

@@ -242,6 +242,18 @@ func TestGetCommitShortStat(t *testing.T) {
 		assert.Equal(t, 6, totalAddition)
 		assert.Equal(t, 0, totalDeletions)
 	})
+
+	t.Run("Renames", func(t *testing.T) {
+		repo, err := OpenRepository(t.Context(), filepath.Join(testReposDir, "renames"))
+		require.NoError(t, err)
+		defer repo.Close()
+
+		numFiles, totalAddition, totalDeletions, err := repo.GetCommitShortStat("f667f3a24223414e3bfbe01ab6e445c703ab8e25")
+		require.NoError(t, err)
+		assert.Equal(t, 1, numFiles)
+		assert.Zero(t, totalAddition)
+		assert.Zero(t, totalDeletions)
+	})
 }
 
 func TestGetShortStat(t *testing.T) {
@@ -301,6 +313,28 @@ func TestGetShortStat(t *testing.T) {
 		assert.Zero(t, totalAdditions)
 		assert.Zero(t, totalDeletions)
 	})
+
+	t.Run("Renames", func(t *testing.T) {
+		repo, err := OpenRepository(t.Context(), filepath.Join(testReposDir, "renames"))
+		require.NoError(t, err)
+		defer repo.Close()
+
+		t.Run("Only rename", func(t *testing.T) {
+			numFiles, totalAdditions, totalDeletions, err := repo.GetShortStat("bc40f00489096a7d4090a609a6572f528e1acb76", "f667f3a24223414e3bfbe01ab6e445c703ab8e25", true)
+			require.NoError(t, err)
+			assert.Equal(t, 1, numFiles)
+			assert.Zero(t, totalAdditions)
+			assert.Zero(t, totalDeletions)
+		})
+
+		t.Run("Too much diverged", func(t *testing.T) {
+			numFiles, totalAdditions, totalDeletions, err := repo.GetShortStat("bc40f00489096a7d4090a609a6572f528e1acb76", "acdee217ada3fea6e503acfb969724cc799fc516", true)
+			require.NoError(t, err)
+			assert.Equal(t, 2, numFiles)
+			assert.Equal(t, 3, totalAdditions)
+			assert.Equal(t, 1, totalDeletions)
+		})
+	})
 }
 
 func TestGetMergeBaseSimple(t *testing.T) {

modules/git/tests/repos/renames/HEAD

@@ -0,0 +1 @@
+ref: refs/heads/main

modules/git/tests/repos/renames/config

@@ -0,0 +1,6 @@
+[core]
+	repositoryformatversion = 0
+	filemode = true
+	bare = true
+[remote "origin"]
+	url = /home/gusted/Desktop/renames

modules/git/tests/repos/renames/objects/info/packs

@@ -0,0 +1,3 @@
+P pack-3c04d9ebf3e2c4620d7142f736b92d739834e2d4.pack
+P pack-d1cbea94fcad36c556cd5921e8df7feff7cbbbb2.pack
+

modules/git/tests/repos/renames/packed-refs

@@ -0,0 +1,2 @@
+# pack-refs with: peeled fully-peeled sorted 
+acdee217ada3fea6e503acfb969724cc799fc516 refs/heads/main