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>

1 files changed, 288 insertions, 0 deletions

diff --git a/services/agit/agit.go b/services/agit/agit.go
new file mode 100644
index 0000000000..a89c255fe7
--- /dev/null
+++ b/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
+}