Make manual merge autodetection optional and add manual merge as merge method (#12543)

* Make auto check manual merge as a chooseable mod and add manual merge way on ui

as title, Before this pr, we use same way with GH to check manually merge.
It good, but in some special cases, misjudgments can occur. and it's hard
to fix this bug. So I add option to allow repo manager block "auto check manual merge"
function, Then it will have same style like gitlab(allow empty pr). and to compensate for
not being able to detect THE PR merge automatically, I added a manual approach.

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

* make swager

* api support

* ping ci

* fix TestPullCreate_EmptyChangesWithCommits

* Apply suggestions from code review

Co-authored-by: zeripath <art27@cantab.net>

* Apply review suggestions and add test

* Apply suggestions from code review

Co-authored-by: zeripath <art27@cantab.net>

* fix build

* test error message

* make fmt

* Fix indentation issues identified by @silverwind

Co-authored-by: silverwind <me@silverwind.io>

* Fix tests and make manually merged disabled error on API the same

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

* a small nit

* fix wrong commit id error

* fix bug

* simple test

* fix test

Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>

4 files changed, 34 insertions, 3 deletions

diff --git a/modules/forms/repo_form.go b/modules/forms/repo_form.go
index 2793acdd5b..ab88aef571 100644
--- a/modules/forms/repo_form.go
+++ b/modules/forms/repo_form.go
@@ -156,6 +156,8 @@ type RepoSettingForm struct {
 	PullsAllowRebase                 bool
 	PullsAllowRebaseMerge            bool
 	PullsAllowSquash                 bool
+	PullsAllowManualMerge            bool
+	EnableAutodetectManualMerge      bool
 	EnableTimetracker                bool
 	AllowOnlyContributorsToTrackTime bool
 	EnableIssueDependencies          bool
@@ -556,11 +558,12 @@ func (f *InitializeLabelsForm) Validate(req *http.Request, errs binding.Errors)
 // swagger:model MergePullRequestOption
 type MergePullRequestForm struct {
 	// required: true
-	// enum: merge,rebase,rebase-merge,squash
-	Do                string `binding:"Required;In(merge,rebase,rebase-merge,squash)"`
+	// enum: merge,rebase,rebase-merge,squash,manually-merged
+	Do                string `binding:"Required;In(merge,rebase,rebase-merge,squash,manually-merged)"`
 	MergeTitleField   string
 	MergeMessageField string
-	ForceMerge        *bool `json:"force_merge,omitempty"`
+	MergeCommitID     string // only used for manually-merged
+	ForceMerge        *bool  `json:"force_merge,omitempty"`
 }
 
 // Validate validates the fields
diff --git a/modules/git/repo_commit.go b/modules/git/repo_commit.go
index 5bf113ba49..ea0aeeb35d 100644
--- a/modules/git/repo_commit.go
+++ b/modules/git/repo_commit.go
@@ -456,3 +456,12 @@ func (repo *Repository) GetCommitsFromIDs(commitIDs []string) (commits *list.Lis
 
 	return commits
 }
+
+// IsCommitInBranch check if the commit is on the branch
+func (repo *Repository) IsCommitInBranch(commitID, branch string) (r bool, err error) {
+	stdout, err := NewCommand("branch", "--contains", commitID, branch).RunInDir(repo.Path)
+	if err != nil {
+		return false, err
+	}
+	return len(stdout) > 0, err
+}
diff --git a/modules/git/repo_commit_test.go b/modules/git/repo_commit_test.go
index 87dd6763b3..3eedaa6b6e 100644
--- a/modules/git/repo_commit_test.go
+++ b/modules/git/repo_commit_test.go
@@ -63,3 +63,18 @@ func TestGetCommitWithBadCommitID(t *testing.T) {
 	assert.Error(t, err)
 	assert.True(t, IsErrNotExist(err))
 }
+
+func TestIsCommitInBranch(t *testing.T) {
+	bareRepo1Path := filepath.Join(testReposDir, "repo1_bare")
+	bareRepo1, err := OpenRepository(bareRepo1Path)
+	assert.NoError(t, err)
+	defer bareRepo1.Close()
+
+	result, err := bareRepo1.IsCommitInBranch("2839944139e0de9737a044f78b0e4b40d989a9e3", "branch1")
+	assert.NoError(t, err)
+	assert.Equal(t, true, result)
+
+	result, err = bareRepo1.IsCommitInBranch("2839944139e0de9737a044f78b0e4b40d989a9e3", "branch2")
+	assert.NoError(t, err)
+	assert.Equal(t, false, result)
+}
diff --git a/modules/structs/repo.go b/modules/structs/repo.go
index d588813b21..c47700cd00 100644
--- a/modules/structs/repo.go
+++ b/modules/structs/repo.go
@@ -167,6 +167,10 @@ type EditRepoOption struct {
 	AllowRebaseMerge *bool `json:"allow_rebase_explicit,omitempty"`
 	// either `true` to allow squash-merging pull requests, or `false` to prevent squash-merging. `has_pull_requests` must be `true`.
 	AllowSquash *bool `json:"allow_squash_merge,omitempty"`
+	// either `true` to allow mark pr as merged manually, or `false` to prevent it. `has_pull_requests` must be `true`.
+	AllowManualMerge *bool `json:"allow_manual_merge,omitempty"`
+	// either `true` to enable AutodetectManualMerge, or `false` to prevent it. `has_pull_requests` must be `true`, Note: In some special cases, misjudgments can occur.
+	AutodetectManualMerge *bool `json:"autodetect_manual_merge,omitempty"`
 	// set to `true` to archive this repository.
 	Archived *bool `json:"archived,omitempty"`
 	// set to a string like `8h30m0s` to set the mirror interval time