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, 161 insertions, 0 deletions

diff --git a/integrations/git_test.go b/integrations/git_test.go
index a9848eaa4c..38d7b29b2b 100644
--- a/integrations/git_test.go
+++ b/integrations/git_test.go
@@ -70,6 +70,7 @@ func testGit(t *testing.T, u *url.URL) {
 		rawTest(t, &httpContext, little, big, littleLFS, bigLFS)
 		mediaTest(t, &httpContext, little, big, littleLFS, bigLFS)
 
+		t.Run("CreateAgitFlowPull", doCreateAgitFlowPull(dstPath, &httpContext, "master", "test/head"))
 		t.Run("BranchProtectMerge", doBranchProtectPRMerge(&httpContext, dstPath))
 		t.Run("CreatePRAndSetManuallyMerged", doCreatePRAndSetManuallyMerged(httpContext, httpContext, dstPath, "master", "test-manually-merge"))
 		t.Run("MergeFork", func(t *testing.T) {
@@ -111,6 +112,7 @@ func testGit(t *testing.T, u *url.URL) {
 			rawTest(t, &sshContext, little, big, littleLFS, bigLFS)
 			mediaTest(t, &sshContext, little, big, littleLFS, bigLFS)
 
+			t.Run("CreateAgitFlowPull", doCreateAgitFlowPull(dstPath, &sshContext, "master", "test/head2"))
 			t.Run("BranchProtectMerge", doBranchProtectPRMerge(&sshContext, dstPath))
 			t.Run("MergeFork", func(t *testing.T) {
 				defer PrintCurrentTest(t)()
@@ -593,3 +595,162 @@ func doBranchDelete(ctx APITestContext, owner, repo, branch string) func(*testin
 		ctx.Session.MakeRequest(t, req, http.StatusOK)
 	}
 }
+
+func doCreateAgitFlowPull(dstPath string, ctx *APITestContext, baseBranch, headBranch string) func(t *testing.T) {
+	return func(t *testing.T) {
+		defer PrintCurrentTest(t)()
+
+		// skip this test if git version is low
+		if git.CheckGitVersionAtLeast("2.29") != nil {
+			return
+		}
+
+		gitRepo, err := git.OpenRepository(dstPath)
+		if !assert.NoError(t, err) {
+			return
+		}
+		defer gitRepo.Close()
+
+		var (
+			pr1, pr2 *models.PullRequest
+			commit   string
+		)
+		repo, err := models.GetRepositoryByOwnerAndName(ctx.Username, ctx.Reponame)
+		if !assert.NoError(t, err) {
+			return
+		}
+
+		pullNum := models.GetCount(t, &models.PullRequest{})
+
+		t.Run("CreateHeadBranch", doGitCreateBranch(dstPath, headBranch))
+
+		t.Run("AddCommit", func(t *testing.T) {
+			err := ioutil.WriteFile(path.Join(dstPath, "test_file"), []byte("## test content"), 0666)
+			if !assert.NoError(t, err) {
+				return
+			}
+
+			err = git.AddChanges(dstPath, true)
+			assert.NoError(t, err)
+
+			err = git.CommitChanges(dstPath, git.CommitChangesOptions{
+				Committer: &git.Signature{
+					Email: "user2@example.com",
+					Name:  "user2",
+					When:  time.Now(),
+				},
+				Author: &git.Signature{
+					Email: "user2@example.com",
+					Name:  "user2",
+					When:  time.Now(),
+				},
+				Message: "Testing commit 1",
+			})
+			assert.NoError(t, err)
+			commit, err = gitRepo.GetRefCommitID("HEAD")
+			assert.NoError(t, err)
+		})
+
+		t.Run("Push", func(t *testing.T) {
+			_, err := git.NewCommand("push", "origin", "HEAD:refs/for/master", "-o", "topic="+headBranch).RunInDir(dstPath)
+			if !assert.NoError(t, err) {
+				return
+			}
+			models.AssertCount(t, &models.PullRequest{}, pullNum+1)
+			pr1 = models.AssertExistsAndLoadBean(t, &models.PullRequest{
+				HeadRepoID: repo.ID,
+				Flow:       models.PullRequestFlowAGit,
+			}).(*models.PullRequest)
+			if !assert.NotEmpty(t, pr1) {
+				return
+			}
+			prMsg, err := doAPIGetPullRequest(*ctx, ctx.Username, ctx.Reponame, pr1.Index)(t)
+			if !assert.NoError(t, err) {
+				return
+			}
+			assert.Equal(t, "user2/"+headBranch, pr1.HeadBranch)
+			assert.Equal(t, false, prMsg.HasMerged)
+			assert.Contains(t, "Testing commit 1", prMsg.Body)
+			assert.Equal(t, commit, prMsg.Head.Sha)
+
+			_, err = git.NewCommand("push", "origin", "HEAD:refs/for/master/test/"+headBranch).RunInDir(dstPath)
+			if !assert.NoError(t, err) {
+				return
+			}
+			models.AssertCount(t, &models.PullRequest{}, pullNum+2)
+			pr2 = models.AssertExistsAndLoadBean(t, &models.PullRequest{
+				HeadRepoID: repo.ID,
+				Index:      pr1.Index + 1,
+				Flow:       models.PullRequestFlowAGit,
+			}).(*models.PullRequest)
+			if !assert.NotEmpty(t, pr2) {
+				return
+			}
+			prMsg, err = doAPIGetPullRequest(*ctx, ctx.Username, ctx.Reponame, pr2.Index)(t)
+			if !assert.NoError(t, err) {
+				return
+			}
+			assert.Equal(t, "user2/test/"+headBranch, pr2.HeadBranch)
+			assert.Equal(t, false, prMsg.HasMerged)
+		})
+
+		if pr1 == nil || pr2 == nil {
+			return
+		}
+
+		t.Run("AddCommit2", func(t *testing.T) {
+			err := ioutil.WriteFile(path.Join(dstPath, "test_file"), []byte("## test content \n ## test content 2"), 0666)
+			if !assert.NoError(t, err) {
+				return
+			}
+
+			err = git.AddChanges(dstPath, true)
+			assert.NoError(t, err)
+
+			err = git.CommitChanges(dstPath, git.CommitChangesOptions{
+				Committer: &git.Signature{
+					Email: "user2@example.com",
+					Name:  "user2",
+					When:  time.Now(),
+				},
+				Author: &git.Signature{
+					Email: "user2@example.com",
+					Name:  "user2",
+					When:  time.Now(),
+				},
+				Message: "Testing commit 2",
+			})
+			assert.NoError(t, err)
+			commit, err = gitRepo.GetRefCommitID("HEAD")
+			assert.NoError(t, err)
+		})
+
+		t.Run("Push2", func(t *testing.T) {
+			_, err := git.NewCommand("push", "origin", "HEAD:refs/for/master", "-o", "topic="+headBranch).RunInDir(dstPath)
+			if !assert.NoError(t, err) {
+				return
+			}
+			models.AssertCount(t, &models.PullRequest{}, pullNum+2)
+			prMsg, err := doAPIGetPullRequest(*ctx, ctx.Username, ctx.Reponame, pr1.Index)(t)
+			if !assert.NoError(t, err) {
+				return
+			}
+			assert.Equal(t, false, prMsg.HasMerged)
+			assert.Equal(t, commit, prMsg.Head.Sha)
+
+			_, err = git.NewCommand("push", "origin", "HEAD:refs/for/master/test/"+headBranch).RunInDir(dstPath)
+			if !assert.NoError(t, err) {
+				return
+			}
+			models.AssertCount(t, &models.PullRequest{}, pullNum+2)
+			prMsg, err = doAPIGetPullRequest(*ctx, ctx.Username, ctx.Reponame, pr2.Index)(t)
+			if !assert.NoError(t, err) {
+				return
+			}
+			assert.Equal(t, false, prMsg.HasMerged)
+			assert.Equal(t, commit, prMsg.Head.Sha)
+		})
+		t.Run("Merge", doAPIMergePullRequest(*ctx, ctx.Username, ctx.Reponame, pr1.Index))
+		t.Run("CheckoutMasterAgain", doGitCheckoutBranch(dstPath, "master"))
+	}
+}