fix(repository): git push to an adopted repository fails

Fix adopt repository has empty object name in database (#31333)

Fix #31330
Fix #31311

A workaround to fix the old database is to update object_format_name to
`sha1` if it's empty or null.

(cherry picked from commit 1968c2222dcf47ebd1697afb4e79a81e74702d31)

With tests services/repository/adopt_test.go

(cherry picked from commit 8efef06fb1)

modules/repository/branch.go

@@ -45,6 +45,7 @@ func SyncRepoBranchesWithRepo(ctx context.Context, repo *repo_model.Repository,
 	if err != nil {
 		return 0, fmt.Errorf("UpdateRepository: %w", err)
 	}
+	repo.ObjectFormatName = objFmt.Name() // keep consistent with db
 
 	allBranches := container.Set[string]{}
 	{

release-notes/8.0.0/fix/4149.md

@@ -0,0 +1 @@
+git push to an adopted repository fails

services/repository/adopt_test.go

@@ -10,9 +10,12 @@ import (
 
 	"code.gitea.io/gitea/models/db"
 	"code.gitea.io/gitea/models/unittest"
+	user_model "code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/setting"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestCheckUnadoptedRepositories_Add(t *testing.T) {
@@ -83,3 +86,30 @@ func TestListUnadoptedRepositories_ListOptions(t *testing.T) {
 	assert.Equal(t, 2, count)
 	assert.Equal(t, unadoptedList[1], repoNames[0])
 }
+
+func TestAdoptRepository(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+	username := "user2"
+
+	unadopted := "unadopted"
+	assert.NoError(t, unittest.CopyDir(
+		"../../modules/git/tests/repos/repo1_bare",
+		path.Join(setting.RepoRootPath, username, unadopted+".git"),
+	))
+
+	opts := db.ListOptions{Page: 1, PageSize: 1}
+	repoNames, _, err := ListUnadoptedRepositories(db.DefaultContext, "", &opts)
+	require.NoError(t, err)
+	require.Contains(t, repoNames, path.Join(username, unadopted))
+
+	doer := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 1})
+	owner := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
+	repo, err := AdoptRepository(db.DefaultContext, doer, owner, CreateRepoOptions{
+		Name:        unadopted,
+		Description: "description",
+		IsPrivate:   false,
+		AutoInit:    true,
+	})
+	assert.NoError(t, err)
+	assert.Equal(t, git.Sha1ObjectFormat.Name(), repo.ObjectFormatName)
+}