fix: correctly get stats for API commits (#8756)

- Instead of generating a patch and parsing its contents, use a faster and simple way to get it via `--shortstat`.
- Resolves forgejo/forgejo#8725
- Regression of forgejo/forgejo#7682
- Adds unit test.
- Adds integration test.

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/8756
Reviewed-by: Earl Warren <earl-warren@noreply.codeberg.org>
Co-authored-by: Gusted <postmaster@gusted.xyz>
Co-committed-by: Gusted <postmaster@gusted.xyz>

modules/git/repo_compare.go

@@ -183,6 +183,17 @@ func (repo *Repository) GetDiffShortStat(base, head string) (numFiles, totalAddi
 	return numFiles, totalAdditions, totalDeletions, err
 }
 
+// GetCommitStat 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)
+	stdout, _, err := cmd.RunStdString(&RunOpts{Dir: repo.Path})
+	if err != nil {
+		return 0, 0, 0, err
+	}
+
+	return parseDiffStat(stdout)
+}
+
 // GetDiffShortStat counts number of changed files, number of additions and deletions
 func GetDiffShortStat(ctx context.Context, repoPath string, trustedArgs TrustedCmdArgs, dynamicArgs ...string) (numFiles, totalAdditions, totalDeletions int, err error) {
 	// Now if we call:

modules/git/repo_compare_test.go

@@ -1,4 +1,5 @@
 // Copyright 2018 The Gitea Authors. All rights reserved.
+// Copyright 2025 The Forgejo Authors. All rights reserved.
 // SPDX-License-Identifier: MIT
 
 package git
@@ -162,3 +163,83 @@ func TestGetCommitFilesChanged(t *testing.T) {
 		assert.ElementsMatch(t, tc.files, changedFiles)
 	}
 }
+
+func TestGetCommitShortStat(t *testing.T) {
+	t.Run("repo1_bare", func(t *testing.T) {
+		repo, err := openRepositoryWithDefaultContext(filepath.Join(testReposDir, "repo1_bare"))
+		if err != nil {
+			require.NoError(t, err)
+			return
+		}
+		defer repo.Close()
+
+		numFiles, totalAddition, totalDeletions, err := repo.GetCommitShortStat("ce064814f4a0d337b333e646ece456cd39fab612")
+		require.NoError(t, err)
+		assert.Equal(t, 0, numFiles)
+		assert.Equal(t, 0, totalAddition)
+		assert.Equal(t, 0, totalDeletions)
+
+		numFiles, totalAddition, totalDeletions, err = repo.GetCommitShortStat("feaf4ba6bc635fec442f46ddd4512416ec43c2c2")
+		require.NoError(t, err)
+		assert.Equal(t, 0, numFiles)
+		assert.Equal(t, 0, totalAddition)
+		assert.Equal(t, 0, totalDeletions)
+
+		numFiles, totalAddition, totalDeletions, err = repo.GetCommitShortStat("37991dec2c8e592043f47155ce4808d4580f9123")
+		require.NoError(t, err)
+		assert.Equal(t, 1, numFiles)
+		assert.Equal(t, 1, totalAddition)
+		assert.Equal(t, 0, totalDeletions)
+
+		numFiles, totalAddition, totalDeletions, err = repo.GetCommitShortStat("6fbd69e9823458e6c4a2fc5c0f6bc022b2f2acd1")
+		require.NoError(t, err)
+		assert.Equal(t, 2, numFiles)
+		assert.Equal(t, 2, totalAddition)
+		assert.Equal(t, 0, totalDeletions)
+
+		numFiles, totalAddition, totalDeletions, err = repo.GetCommitShortStat("8006ff9adbf0cb94da7dad9e537e53817f9fa5c0")
+		require.NoError(t, err)
+		assert.Equal(t, 2, numFiles)
+		assert.Equal(t, 2, totalAddition)
+		assert.Equal(t, 0, totalDeletions)
+
+		numFiles, totalAddition, totalDeletions, err = repo.GetCommitShortStat("8d92fc957a4d7cfd98bc375f0b7bb189a0d6c9f2")
+		require.NoError(t, err)
+		assert.Equal(t, 1, numFiles)
+		assert.Equal(t, 1, totalAddition)
+		assert.Equal(t, 0, totalDeletions)
+
+		numFiles, totalAddition, totalDeletions, err = repo.GetCommitShortStat("95bb4d39648ee7e325106df01a621c530863a653")
+		require.NoError(t, err)
+		assert.Equal(t, 1, numFiles)
+		assert.Equal(t, 1, totalAddition)
+		assert.Equal(t, 0, totalDeletions)
+	})
+
+	t.Run("repo6_blame_sha256", func(t *testing.T) {
+		repo, err := openRepositoryWithDefaultContext(filepath.Join(testReposDir, "repo6_blame_sha256"))
+		if err != nil {
+			require.NoError(t, err)
+			return
+		}
+		defer repo.Close()
+
+		numFiles, totalAddition, totalDeletions, err := repo.GetCommitShortStat("e2f5660e15159082902960af0ed74fc144921d2b0c80e069361853b3ece29ba3")
+		require.NoError(t, err)
+		assert.Equal(t, 1, numFiles)
+		assert.Equal(t, 1, totalAddition)
+		assert.Equal(t, 0, totalDeletions)
+
+		numFiles, totalAddition, totalDeletions, err = repo.GetCommitShortStat("9347b0198cd1f25017579b79d0938fa89dba34ad2514f0dd92f6bc975ed1a2fe")
+		require.NoError(t, err)
+		assert.Equal(t, 1, numFiles)
+		assert.Equal(t, 1, totalAddition)
+		assert.Equal(t, 1, totalDeletions)
+
+		numFiles, totalAddition, totalDeletions, err = repo.GetCommitShortStat("ab2b57a4fa476fb2edb74dafa577caf918561abbaa8fba0c8dc63c412e17a7cc")
+		require.NoError(t, err)
+		assert.Equal(t, 1, numFiles)
+		assert.Equal(t, 6, totalAddition)
+		assert.Equal(t, 0, totalDeletions)
+	})
+}

services/convert/git_commit.go

@@ -15,7 +15,6 @@ import (
 	api "forgejo.org/modules/structs"
 	"forgejo.org/modules/util"
 	ctx "forgejo.org/services/context"
-	"forgejo.org/services/gitdiff"
 )
 
 // ToCommitUser convert a git.Signature to an api.CommitUser
@@ -210,17 +209,15 @@ func ToCommit(ctx context.Context, repo *repo_model.Repository, gitRepo *git.Rep
 
 	// Get diff stats for commit
 	if opts.Stat {
-		diff, _, err := gitdiff.GetDiffSimple(ctx, gitRepo, &gitdiff.DiffOptions{
+		_, totalAdditions, totalDeletions, err := gitRepo.GetCommitShortStat(commit.ID.String())
-			AfterCommitID: commit.ID.String(),
-		})
 		if err != nil {
 			return nil, err
 		}
 
 		res.Stats = &api.CommitStats{
-			Total:     diff.TotalAddition + diff.TotalDeletion,
+			Total:     totalAdditions + totalDeletions,
-			Additions: diff.TotalAddition,
+			Additions: totalAdditions,
-			Deletions: diff.TotalDeletion,
+			Deletions: totalDeletions,
 		}
 	}
 

tests/integration/api_repo_git_commits_test.go

@@ -231,3 +231,22 @@ func TestGetFileHistoryNotOnMaster(t *testing.T) {
 
 	assert.Equal(t, "1", resp.Header().Get("X-Total"))
 }
+
+func TestAPIReposGitCommit(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+
+	session := loginUser(t, "user2")
+	token := getTokenForLoggedInUser(t, session, auth_model.AccessTokenScopeReadRepository)
+
+	req := NewRequest(t, "GET", "/api/v1/repos/user2/repo16/git/commits/f27c2b2b03dcab38beaf89b0ab4ff61f6de63441").
+		AddTokenAuth(token)
+	resp := MakeRequest(t, req, http.StatusOK)
+
+	var apiData api.Commit
+	DecodeJSON(t, resp, &apiData)
+
+	assert.Equal(t, "f27c2b2b03dcab38beaf89b0ab4ff61f6de63441", apiData.CommitMeta.SHA)
+	assert.Equal(t, 1, apiData.Stats.Total)
+	assert.Equal(t, 1, apiData.Stats.Additions)
+	assert.Equal(t, 0, apiData.Stats.Deletions)
+}