enhance(api): add GitHub-compatible /repos/{owner}/{repo}/commits/{ref} endpoint (#38770)

Gitea currently exposes the endpoint:
 
`GET /repos/{owner}/{repo}/git/commits/{sha}`
 
to retrieve a single commit. However, GitHub provides the equivalent
endpoint as:
 
`GET /repos/{owner}/{repo}/commits/{ref}`
 
Applications integrating with both GitHub and Gitea must implement
platform-specific logic to use different endpoints, reducing API
compatibility.
 
Fixes #38225

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: Giteabot <teabot@gitea.io>

routers/api/v1/api.go

@@ -1484,7 +1484,11 @@ func Routes() *web.Router {
 						Post(reqToken(), reqRepoWriter(unit.TypeCode), bind(api.CreateStatusOption{}), repo.NewCommitStatus)
 				}, reqRepoReader(unit.TypeCode))
 				m.Group("/commits", func() {
-					m.Get("", context.ReferencesGitRepo(), repo.GetAllCommits)
+					m.Group("", func() {
+						m.Get("", repo.GetAllCommits)
+						m.Get("/{sha}", repo.GetSingleCommit) // GitHub-compatible endpoint
+						m.Get("/{sha}.{diffType:diff|patch}", repo.DownloadCommitDiffOrPatch)
+					}, context.ReferencesGitRepo(true))
 					m.PathGroup("/*", func(g *web.RouterPathGroup) {
 						// Mis-configured reverse proxy might decode the `%2F` to slash ahead, so we need to support both formats (escaped, unescaped) here.
 						// It also matches GitHub's behavior

routers/api/v1/repo/commits.go

@@ -24,7 +24,7 @@ import (
 func GetSingleCommit(ctx *context.APIContext) {
 	// swagger:operation GET /repos/{owner}/{repo}/git/commits/{sha} repository repoGetSingleCommit
 	// ---
-	// summary: Get a single commit from a repository
+	// summary: Get a single commit from a repository, it has a GitHub-compatible alias "/repos/{owner}/{repo}/commits/{ref}"
 	// produces:
 	// - application/json
 	// parameters:

templates/swagger/v1-openapi3.generated.json

@@ -20470,7 +20470,7 @@
             "$ref": "#/components/responses/validationError"
           }
         },
-        "summary": "Get a single commit from a repository",
+        "summary": "Get a single commit from a repository, it has a GitHub-compatible alias \"/repos/{owner}/{repo}/commits/{ref}\"",
         "tags": [
           "repository"
         ]

templates/swagger/v1-swagger.generated.json

@@ -9067,7 +9067,7 @@
         "tags": [
           "repository"
         ],
-        "summary": "Get a single commit from a repository",
+        "summary": "Get a single commit from a repository, it has a GitHub-compatible alias \"/repos/{owner}/{repo}/commits/{ref}\"",
         "operationId": "repoGetSingleCommit",
         "parameters": [
           {

tests/integration/api_repo_git_commits_test.go

@@ -26,22 +26,15 @@ func compareCommitFiles(t *testing.T, expect []string, files []*api.CommitAffect
 
 func TestAPIReposGitCommits(t *testing.T) {
 	defer tests.PrepareTestEnv(t)()
-	user := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
-	// Login as User2.
-	session := loginUser(t, user.Name)
+	user2 := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
+	session := loginUser(t, user2.Name)
 	token := getTokenForLoggedInUser(t, session, auth_model.AccessTokenScopeReadRepository)
 
 	// check invalid requests
-	req := NewRequestf(t, "GET", "/api/v1/repos/%s/repo1/git/commits/12345", user.Name).
-		AddTokenAuth(token)
-	MakeRequest(t, req, http.StatusNotFound)
-
-	req = NewRequestf(t, "GET", "/api/v1/repos/%s/repo1/git/commits/..", user.Name).
-		AddTokenAuth(token)
+	req := NewRequestf(t, "GET", "/api/v1/repos/%s/repo1/git/commits/..", user2.Name).AddTokenAuth(token)
 	MakeRequest(t, req, http.StatusUnprocessableEntity)
 
-	req = NewRequestf(t, "GET", "/api/v1/repos/%s/repo1/git/commits/branch-not-exist", user.Name).
-		AddTokenAuth(token)
+	req = NewRequestf(t, "GET", "/api/v1/repos/%s/repo1/git/commits/ref-not-exist", user2.Name).AddTokenAuth(token)
 	MakeRequest(t, req, http.StatusNotFound)
 
 	for _, ref := range [...]string{
@@ -50,8 +43,10 @@ func TestAPIReposGitCommits(t *testing.T) {
 		"65f1",   // short sha
 		"65f1bf27bc3bf70f64657658635e66094edbcb4d", // full sha
 	} {
-		req := NewRequestf(t, "GET", "/api/v1/repos/%s/repo1/git/commits/%s", user.Name, ref).
-			AddTokenAuth(token)
+		req = NewRequestf(t, "GET", "/api/v1/repos/%s/repo1/git/commits/%s", user2.Name, ref).AddTokenAuth(token)
+		MakeRequest(t, req, http.StatusOK)
+		// GitHub-compatible
+		req = NewRequestf(t, "GET", "/api/v1/repos/%s/repo1/commits/%s", user2.Name, ref).AddTokenAuth(token)
 		MakeRequest(t, req, http.StatusOK)
 	}
 }