Add agit flow support in gitea (#14295)

* feature: add agit flow support

ref: https://git-repo.info/en/2020/03/agit-flow-and-git-repo/

example:

```Bash
git checkout -b test
echo "test" >> README.md
git commit -m "test"
git push origin HEAD:refs/for/master -o topic=test
```

Signed-off-by: a1012112796 <1012112796@qq.com>

* fix lint

* simplify code add fix some nits

* update merge help message

* Apply suggestions from code review. Thanks @jiangxin

* add forced-update message

* fix lint

* splite writePktLine

* add refs/for/<target-branch>/<topic-branch> support also

* Add test code add fix api

* fix lint

* fix test

* skip test if git version < 2.29

* try test with git 2.30.1

* fix permission check bug

* fix some nit

* logic implify and test code update

* fix bug

* apply suggestions from code review

* prepare for merge

Signed-off-by: Andrew Thornton <art27@cantab.net>

* fix permission check bug

- test code update
- apply suggestions from code review @zeripath

Signed-off-by: a1012112796 <1012112796@qq.com>

* fix bug when target branch isn't exist

* prevent some special push and fix some nits

* fix lint

* try splite

* Apply suggestions from code review

- fix permission check
- handle user rename

* fix version negotiation

* remane

* fix template

* handle empty repo

* ui: fix  branch link under the title

* fix nits

Co-authored-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

services/agit/agit.go

@@ -0,0 +1,288 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package agit
+
+import (
+	"fmt"
+	"net/http"
+	"os"
+	"strings"
+
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/context"
+	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/notification"
+	"code.gitea.io/gitea/modules/private"
+	pull_service "code.gitea.io/gitea/services/pull"
+)
+
+// ProcRecive handle proc receive work
+func ProcRecive(ctx *context.PrivateContext, opts *private.HookOptions) []private.HockProcReceiveRefResult {
+	// TODO: Add more options?
+	var (
+		topicBranch string
+		title       string
+		description string
+		forcePush   bool
+	)
+
+	results := make([]private.HockProcReceiveRefResult, 0, len(opts.OldCommitIDs))
+	repo := ctx.Repo.Repository
+	gitRepo := ctx.Repo.GitRepo
+	ownerName := ctx.Repo.Repository.OwnerName
+	repoName := ctx.Repo.Repository.Name
+
+	topicBranch = opts.GitPushOptions["topic"]
+	_, forcePush = opts.GitPushOptions["force-push"]
+
+	for i := range opts.OldCommitIDs {
+		if opts.NewCommitIDs[i] == git.EmptySHA {
+			results = append(results, private.HockProcReceiveRefResult{
+				OriginalRef: opts.RefFullNames[i],
+				OldOID:      opts.OldCommitIDs[i],
+				NewOID:      opts.NewCommitIDs[i],
+				Err:         "Can't delete not exist branch",
+			})
+			continue
+		}
+
+		if !strings.HasPrefix(opts.RefFullNames[i], git.PullRequestPrefix) {
+			results = append(results, private.HockProcReceiveRefResult{
+				IsNotMatched: true,
+				OriginalRef:  opts.RefFullNames[i],
+			})
+			continue
+		}
+
+		baseBranchName := opts.RefFullNames[i][len(git.PullRequestPrefix):]
+		curentTopicBranch := ""
+		if !gitRepo.IsBranchExist(baseBranchName) {
+			// try match refs/for/<target-branch>/<topic-branch>
+			for p, v := range baseBranchName {
+				if v == '/' && gitRepo.IsBranchExist(baseBranchName[:p]) && p != len(baseBranchName)-1 {
+					curentTopicBranch = baseBranchName[p+1:]
+					baseBranchName = baseBranchName[:p]
+					break
+				}
+			}
+		}
+
+		if len(topicBranch) == 0 && len(curentTopicBranch) == 0 {
+			results = append(results, private.HockProcReceiveRefResult{
+				OriginalRef: opts.RefFullNames[i],
+				OldOID:      opts.OldCommitIDs[i],
+				NewOID:      opts.NewCommitIDs[i],
+				Err:         "topic-branch is not set",
+			})
+			continue
+		}
+
+		headBranch := ""
+		userName := strings.ToLower(opts.UserName)
+
+		if len(curentTopicBranch) == 0 {
+			curentTopicBranch = topicBranch
+		}
+
+		// because different user maybe want to use same topic,
+		// So it's better to make sure the topic branch name
+		// has user name prefix
+		if !strings.HasPrefix(curentTopicBranch, userName+"/") {
+			headBranch = userName + "/" + curentTopicBranch
+		} else {
+			headBranch = curentTopicBranch
+		}
+
+		pr, err := models.GetUnmergedPullRequest(repo.ID, repo.ID, headBranch, baseBranchName, models.PullRequestFlowAGit)
+		if err != nil {
+			if !models.IsErrPullRequestNotExist(err) {
+				log.Error("Failed to get unmerged agit flow pull request in repository: %s/%s Error: %v", ownerName, repoName, err)
+				ctx.JSON(http.StatusInternalServerError, map[string]interface{}{
+					"Err": fmt.Sprintf("Failed to get unmerged agit flow pull request in repository: %s/%s Error: %v", ownerName, repoName, err),
+				})
+				return nil
+			}
+
+			// create a new pull request
+			if len(title) == 0 {
+				has := false
+				title, has = opts.GitPushOptions["title"]
+				if !has || len(title) == 0 {
+					commit, err := gitRepo.GetCommit(opts.NewCommitIDs[i])
+					if err != nil {
+						log.Error("Failed to get commit %s in repository: %s/%s Error: %v", opts.NewCommitIDs[i], ownerName, repoName, err)
+						ctx.JSON(http.StatusInternalServerError, map[string]interface{}{
+							"Err": fmt.Sprintf("Failed to get commit %s in repository: %s/%s Error: %v", opts.NewCommitIDs[i], ownerName, repoName, err),
+						})
+						return nil
+					}
+					title = strings.Split(commit.CommitMessage, "\n")[0]
+				}
+				description = opts.GitPushOptions["description"]
+			}
+
+			pusher, err := models.GetUserByID(opts.UserID)
+			if err != nil {
+				log.Error("Failed to get user. Error: %v", err)
+				ctx.JSON(http.StatusInternalServerError, map[string]interface{}{
+					"Err": fmt.Sprintf("Failed to get user. Error: %v", err),
+				})
+				return nil
+			}
+
+			prIssue := &models.Issue{
+				RepoID:   repo.ID,
+				Title:    title,
+				PosterID: pusher.ID,
+				Poster:   pusher,
+				IsPull:   true,
+				Content:  description,
+			}
+
+			pr := &models.PullRequest{
+				HeadRepoID:   repo.ID,
+				BaseRepoID:   repo.ID,
+				HeadBranch:   headBranch,
+				HeadCommitID: opts.NewCommitIDs[i],
+				BaseBranch:   baseBranchName,
+				HeadRepo:     repo,
+				BaseRepo:     repo,
+				MergeBase:    "",
+				Type:         models.PullRequestGitea,
+				Flow:         models.PullRequestFlowAGit,
+			}
+
+			if err := pull_service.NewPullRequest(repo, prIssue, []int64{}, []string{}, pr, []int64{}); err != nil {
+				if models.IsErrUserDoesNotHaveAccessToRepo(err) {
+					ctx.Error(http.StatusBadRequest, "UserDoesNotHaveAccessToRepo", err.Error())
+					return nil
+				}
+				ctx.Error(http.StatusInternalServerError, "NewPullRequest", err.Error())
+				return nil
+			}
+
+			log.Trace("Pull request created: %d/%d", repo.ID, prIssue.ID)
+
+			results = append(results, private.HockProcReceiveRefResult{
+				Ref:         pr.GetGitRefName(),
+				OriginalRef: opts.RefFullNames[i],
+				OldOID:      git.EmptySHA,
+				NewOID:      opts.NewCommitIDs[i],
+			})
+			continue
+		}
+
+		// update exist pull request
+		if err := pr.LoadBaseRepo(); err != nil {
+			log.Error("Unable to load base repository for PR[%d] Error: %v", pr.ID, err)
+			ctx.JSON(http.StatusInternalServerError, map[string]interface{}{
+				"Err": fmt.Sprintf("Unable to load base repository for PR[%d] Error: %v", pr.ID, err),
+			})
+			return nil
+		}
+
+		oldCommitID, err := gitRepo.GetRefCommitID(pr.GetGitRefName())
+		if err != nil {
+			log.Error("Unable to get ref commit id in base repository for PR[%d] Error: %v", pr.ID, err)
+			ctx.JSON(http.StatusInternalServerError, map[string]interface{}{
+				"Err": fmt.Sprintf("Unable to get ref commit id in base repository for PR[%d] Error: %v", pr.ID, err),
+			})
+			return nil
+		}
+
+		if oldCommitID == opts.NewCommitIDs[i] {
+			results = append(results, private.HockProcReceiveRefResult{
+				OriginalRef: opts.RefFullNames[i],
+				OldOID:      opts.OldCommitIDs[i],
+				NewOID:      opts.NewCommitIDs[i],
+				Err:         "new commit is same with old commit",
+			})
+			continue
+		}
+
+		if !forcePush {
+			output, err := git.NewCommand("rev-list", "--max-count=1", oldCommitID, "^"+opts.NewCommitIDs[i]).RunInDirWithEnv(repo.RepoPath(), os.Environ())
+			if err != nil {
+				log.Error("Unable to detect force push between: %s and %s in %-v Error: %v", oldCommitID, opts.NewCommitIDs[i], repo, err)
+				ctx.JSON(http.StatusInternalServerError, private.Response{
+					Err: fmt.Sprintf("Fail to detect force push: %v", err),
+				})
+				return nil
+			} else if len(output) > 0 {
+				results = append(results, private.HockProcReceiveRefResult{
+					OriginalRef: oldCommitID,
+					OldOID:      opts.OldCommitIDs[i],
+					NewOID:      opts.NewCommitIDs[i],
+					Err:         "request `force-push` push option",
+				})
+				continue
+			}
+		}
+
+		pr.HeadCommitID = opts.NewCommitIDs[i]
+		if err = pull_service.UpdateRef(pr); err != nil {
+			log.Error("Failed to update pull ref. Error: %v", err)
+			ctx.JSON(http.StatusInternalServerError, map[string]interface{}{
+				"Err": fmt.Sprintf("Failed to update pull ref. Error: %v", err),
+			})
+			return nil
+		}
+
+		pull_service.AddToTaskQueue(pr)
+		pusher, err := models.GetUserByID(opts.UserID)
+		if err != nil {
+			log.Error("Failed to get user. Error: %v", err)
+			ctx.JSON(http.StatusInternalServerError, map[string]interface{}{
+				"Err": fmt.Sprintf("Failed to get user. Error: %v", err),
+			})
+			return nil
+		}
+		err = pr.LoadIssue()
+		if err != nil {
+			log.Error("Failed to load pull issue. Error: %v", err)
+			ctx.JSON(http.StatusInternalServerError, map[string]interface{}{
+				"Err": fmt.Sprintf("Failed to load pull issue. Error: %v", err),
+			})
+			return nil
+		}
+		comment, err := models.CreatePushPullComment(pusher, pr, oldCommitID, opts.NewCommitIDs[i])
+		if err == nil && comment != nil {
+			notification.NotifyPullRequestPushCommits(pusher, pr, comment)
+		}
+		notification.NotifyPullRequestSynchronized(pusher, pr)
+		isForcePush := comment != nil && comment.IsForcePush
+
+		results = append(results, private.HockProcReceiveRefResult{
+			OldOID:      oldCommitID,
+			NewOID:      opts.NewCommitIDs[i],
+			Ref:         pr.GetGitRefName(),
+			OriginalRef: opts.RefFullNames[i],
+			IsForcePush: isForcePush,
+		})
+	}
+
+	return results
+}
+
+// UserNameChanged hanle user name change for agit flow pull
+func UserNameChanged(user *models.User, newName string) error {
+	pulls, err := models.GetAllUnmergedAgitPullRequestByPoster(user.ID)
+	if err != nil {
+		return err
+	}
+
+	newName = strings.ToLower(newName)
+
+	for _, pull := range pulls {
+		pull.HeadBranch = strings.TrimPrefix(pull.HeadBranch, user.LowerName+"/")
+		pull.HeadBranch = newName + "/" + pull.HeadBranch
+		if err = pull.UpdateCols("head_branch"); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}

services/pull/commit_status.go

@@ -108,13 +108,21 @@ func GetPullRequestCommitStatusState(pr *models.PullRequest) (structs.CommitStat
 	}
 	defer headGitRepo.Close()
 
-	if !headGitRepo.IsBranchExist(pr.HeadBranch) {
+	if pr.Flow == models.PullRequestFlowGithub && !headGitRepo.IsBranchExist(pr.HeadBranch) {
+		return "", errors.New("Head branch does not exist, can not merge")
+	}
+	if pr.Flow == models.PullRequestFlowAGit && !git.IsReferenceExist(headGitRepo.Path, pr.GetGitRefName()) {
 		return "", errors.New("Head branch does not exist, can not merge")
 	}
 
-	sha, err := headGitRepo.GetBranchCommitID(pr.HeadBranch)
+	var sha string
+	if pr.Flow == models.PullRequestFlowGithub {
+		sha, err = headGitRepo.GetBranchCommitID(pr.HeadBranch)
+	} else {
+		sha, err = headGitRepo.GetRefCommitID(pr.GetGitRefName())
+	}
 	if err != nil {
-		return "", errors.Wrap(err, "GetBranchCommitID")
+		return "", err
 	}
 
 	if err := pr.LoadBaseRepo(); err != nil {

services/pull/pull.go

@@ -49,7 +49,12 @@ func NewPullRequest(repo *models.Repository, pull *models.Issue, labelIDs []int6
 	pr.Issue = pull
 	pull.PullRequest = pr
 
-	if err := PushToBaseRepo(pr); err != nil {
+	if pr.Flow == models.PullRequestFlowGithub {
+		err = PushToBaseRepo(pr)
+	} else {
+		err = UpdateRef(pr)
+	}
+	if err != nil {
 		return err
 	}
 
@@ -145,7 +150,7 @@ func ChangeTargetBranch(pr *models.PullRequest, doer *models.User, targetBranch
 	}
 
 	// Check if pull request for the new target branch already exists
-	existingPr, err := models.GetUnmergedPullRequest(pr.HeadRepoID, pr.BaseRepoID, pr.HeadBranch, targetBranch)
+	existingPr, err := models.GetUnmergedPullRequest(pr.HeadRepoID, pr.BaseRepoID, pr.HeadBranch, targetBranch, models.PullRequestFlowGithub)
 	if existingPr != nil {
 		return models.ErrPullRequestAlreadyExists{
 			ID:         existingPr.ID,
@@ -281,8 +286,12 @@ func AddTestPullRequestTask(doer *models.User, repoID int64, branch string, isSy
 
 		for _, pr := range prs {
 			log.Trace("Updating PR[%d]: composing new test task", pr.ID)
-			if err := PushToBaseRepo(pr); err != nil {
-				log.Error("PushToBaseRepo: %v", err)
+			if pr.Flow == models.PullRequestFlowGithub {
+				if err := PushToBaseRepo(pr); err != nil {
+					log.Error("PushToBaseRepo: %v", err)
+					continue
+				}
+			} else {
 				continue
 			}
 
@@ -451,6 +460,22 @@ func pushToBaseRepoHelper(pr *models.PullRequest, prefixHeadBranch string) (err
 	return nil
 }
 
+// UpdateRef update refs/pull/id/head directly for agit flow pull request
+func UpdateRef(pr *models.PullRequest) (err error) {
+	log.Trace("UpdateRef[%d]: upgate pull request ref in base repo '%s'", pr.ID, pr.GetGitRefName())
+	if err := pr.LoadBaseRepo(); err != nil {
+		log.Error("Unable to load base repository for PR[%d] Error: %v", pr.ID, err)
+		return err
+	}
+
+	_, err = git.NewCommand("update-ref", pr.GetGitRefName(), pr.HeadCommitID).RunInDir(pr.BaseRepo.RepoPath())
+	if err != nil {
+		log.Error("Unable to update ref in base repository for PR[%d] Error: %v", pr.ID, err)
+	}
+
+	return err
+}
+
 type errlist []error
 
 func (errs errlist) Error() string {
@@ -562,7 +587,17 @@ func GetSquashMergeCommitMessages(pr *models.PullRequest) string {
 	}
 	defer gitRepo.Close()
 
-	headCommit, err := gitRepo.GetBranchCommit(pr.HeadBranch)
+	var headCommit *git.Commit
+	if pr.Flow == models.PullRequestFlowGithub {
+		headCommit, err = gitRepo.GetBranchCommit(pr.HeadBranch)
+	} else {
+		pr.HeadCommitID, err = gitRepo.GetRefCommitID(pr.GetGitRefName())
+		if err != nil {
+			log.Error("Unable to get head commit: %s Error: %v", pr.GetGitRefName(), err)
+			return ""
+		}
+		headCommit, err = gitRepo.GetCommit(pr.HeadCommitID)
+	}
 	if err != nil {
 		log.Error("Unable to get head commit: %s Error: %v", pr.HeadBranch, err)
 		return ""
@@ -781,9 +816,20 @@ func IsHeadEqualWithBranch(pr *models.PullRequest, branchName string) (bool, err
 	}
 	defer headGitRepo.Close()
 
-	headCommit, err := headGitRepo.GetBranchCommit(pr.HeadBranch)
-	if err != nil {
-		return false, err
+	var headCommit *git.Commit
+	if pr.Flow == models.PullRequestFlowGithub {
+		headCommit, err = headGitRepo.GetBranchCommit(pr.HeadBranch)
+		if err != nil {
+			return false, err
+		}
+	} else {
+		pr.HeadCommitID, err = baseGitRepo.GetRefCommitID(pr.GetGitRefName())
+		if err != nil {
+			return false, err
+		}
+		if headCommit, err = baseGitRepo.GetCommit(pr.HeadCommitID); err != nil {
+			return false, err
+		}
 	}
 	return baseCommit.HasPreviousCommit(headCommit.ID)
 }

services/pull/temp_repo.go

@@ -140,7 +140,15 @@ func createTemporaryRepo(pr *models.PullRequest) (string, error) {
 
 	trackingBranch := "tracking"
 	// Fetch head branch
-	if err := git.NewCommand("fetch", "--no-tags", remoteRepoName, git.BranchPrefix+pr.HeadBranch+":"+trackingBranch).RunInDirPipeline(tmpBasePath, &outbuf, &errbuf); err != nil {
+	var headBranch string
+	if pr.Flow == models.PullRequestFlowGithub {
+		headBranch = git.BranchPrefix + pr.HeadBranch
+	} else if len(pr.HeadCommitID) == 40 { // for not created pull request
+		headBranch = pr.HeadCommitID
+	} else {
+		headBranch = pr.GetGitRefName()
+	}
+	if err := git.NewCommand("fetch", "--no-tags", remoteRepoName, headBranch+":"+trackingBranch).RunInDirPipeline(tmpBasePath, &outbuf, &errbuf); err != nil {
 		if err := models.RemoveTemporaryPath(tmpBasePath); err != nil {
 			log.Error("CreateTempRepo: RemoveTemporaryPath: %s", err)
 		}
@@ -150,7 +158,7 @@ func createTemporaryRepo(pr *models.PullRequest) (string, error) {
 			}
 		}
 		log.Error("Unable to fetch head_repo head branch [%s:%s -> tracking in %s]: %v:\n%s\n%s", pr.HeadRepo.FullName(), pr.HeadBranch, tmpBasePath, err, outbuf.String(), errbuf.String())
-		return "", fmt.Errorf("Unable to fetch head_repo head branch [%s:%s -> tracking in tmpBasePath]: %v\n%s\n%s", pr.HeadRepo.FullName(), pr.HeadBranch, err, outbuf.String(), errbuf.String())
+		return "", fmt.Errorf("Unable to fetch head_repo head branch [%s:%s -> tracking in tmpBasePath]: %v\n%s\n%s", pr.HeadRepo.FullName(), headBranch, err, outbuf.String(), errbuf.String())
 	}
 	outbuf.Reset()
 	errbuf.Reset()

services/pull/update.go

@@ -22,6 +22,11 @@ func Update(pull *models.PullRequest, doer *models.User, message string) error {
 		BaseBranch: pull.HeadBranch,
 	}
 
+	if pull.Flow == models.PullRequestFlowAGit {
+		// TODO: Not support update agit flow pull request's head branch
+		return fmt.Errorf("Not support update agit flow pull request's head branch")
+	}
+
 	if err := pr.LoadHeadRepo(); err != nil {
 		log.Error("LoadHeadRepo: %v", err)
 		return fmt.Errorf("LoadHeadRepo: %v", err)
@@ -48,6 +53,10 @@ func Update(pull *models.PullRequest, doer *models.User, message string) error {
 
 // IsUserAllowedToUpdate check if user is allowed to update PR with given permissions and branch protections
 func IsUserAllowedToUpdate(pull *models.PullRequest, user *models.User) (bool, error) {
+	if pull.Flow == models.PullRequestFlowAGit {
+		return false, nil
+	}
+
 	if user == nil {
 		return false, nil
 	}