Auto merge pull requests when all checks succeeded

Signed-off-by: kolaente <k@knt.li>

models/migrations/migrations.go

@@ -210,6 +210,8 @@ var migrations = []Migration{
 	NewMigration("Add Branch Protection Block Outdated Branch", addBlockOnOutdatedBranch),
 	// v138 -> v139
 	NewMigration("Add ResolveDoerID to Comment table", addResolveDoerIDCommentColumn),
+	// v139 -> v140
+	NewMigration("Add auto merge table", addAutoMergeTable),
 }
 
 // GetCurrentDBVersion returns the current db version

models/migrations/v139.go

@@ -0,0 +1,20 @@
+// Copyright 2020 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 migrations
+
+import "xorm.io/xorm"
+
+func addAutoMergeTable(x *xorm.Engine) error {
+	type MergeStyle string
+	type ScheduledPullRequestMerge struct {
+		ID         int64      `xorm:"pk autoincr"`
+		PullID     int64      `xorm:"BIGINT"`
+		UserID     int64      `xorm:"BIGINT"`
+		MergeStyle MergeStyle `xorm:"varchar(50)"`
+		Message    string     `xorm:"TEXT"`
+	}
+
+	return x.Sync2(&ScheduledPullRequestMerge{})
+}

models/pull.go

@@ -636,3 +636,16 @@ func (pr *PullRequest) updateCommitDivergence(e Engine, ahead, behind int) error
 func (pr *PullRequest) IsSameRepo() bool {
 	return pr.BaseRepoID == pr.HeadRepoID
 }
+
+// GetPullRequestByHeadBranch returns a pr by head branch
+func GetPullRequestByHeadBranch(headBranch string, repo *Repository) (pr *PullRequest, err error) {
+	pr = &PullRequest{}
+	exists, err := x.Where("head_branch = ? AND head_repo_id = ?", headBranch, repo.ID).Get(pr)
+	if !exists {
+		return nil, ErrPullRequestNotExist{
+			HeadBranch: headBranch,
+			HeadRepoID: repo.ID,
+		}
+	}
+	return
+}

models/scheduled_pull_request_merge.go

@@ -0,0 +1,55 @@
+// Copyright 2019 Gitea. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package models
+
+import "code.gitea.io/gitea/modules/timeutil"
+
+// ScheduledPullRequestMerge represents a pull request scheduled for merging when checks succeed
+type ScheduledPullRequestMerge struct {
+	ID          int64              `xorm:"pk autoincr"`
+	PullID      int64              `xorm:"BIGINT"`
+	UserID      int64              `xorm:"BIGINT"`
+	User        *User              `xorm:"-"`
+	MergeStyle  MergeStyle         `xorm:"varchar(50)"`
+	Message     string             `xorm:"TEXT"`
+	CreatedUnix timeutil.TimeStamp `xorm:"created"`
+}
+
+// ScheduleAutoMerge schedules a pull request to be merged when all checks succeed
+func ScheduleAutoMerge(opts *ScheduledPullRequestMerge) (err error) {
+	// Check if we already have a merge scheduled for that pull request
+	exists, err := x.Exist(&ScheduledPullRequestMerge{PullID: opts.PullID})
+	if err != nil {
+		return
+	}
+	if exists {
+		// Maybe FIXME: Should we return a custom error here?
+		return nil
+	}
+
+	_, err = x.Insert(opts)
+	return err
+}
+
+// GetScheduledMergeRequestByPullID gets a scheduled pull request merge by pull request id
+func GetScheduledMergeRequestByPullID(pullID int64) (exists bool, scheduledPRM *ScheduledPullRequestMerge, err error) {
+	scheduledPRM = &ScheduledPullRequestMerge{}
+	exists, err = x.Where("pull_id = ?", pullID).Get(scheduledPRM)
+	if err != nil || !exists {
+		return
+	}
+	scheduledPRM.User, err = getUserByID(x, scheduledPRM.UserID)
+	return
+}
+
+// RemoveScheduledMergeRequest cancels a previously scheduled pull request
+func RemoveScheduledMergeRequest(scheduledPR *ScheduledPullRequestMerge) (err error) {
+	if scheduledPR.ID == 0 && scheduledPR.PullID != 0 {
+		_, err = x.Where("pull_id = ?", scheduledPR.PullID).Delete(&ScheduledPullRequestMerge{})
+		return
+	}
+	_, err = x.Where("id = ? AND pull_id = ?", scheduledPR.ID, scheduledPR.PullID).Delete(&ScheduledPullRequestMerge{})
+	return
+}

modules/auth/repo_form.go

@@ -483,10 +483,11 @@ func (f *InitializeLabelsForm) Validate(ctx *macaron.Context, errs binding.Error
 type MergePullRequestForm struct {
 	// required: true
 	// enum: merge,rebase,rebase-merge,squash
-	Do                string `binding:"Required;In(merge,rebase,rebase-merge,squash)"`
-	MergeTitleField   string
-	MergeMessageField string
-	ForceMerge        *bool `json:"force_merge,omitempty"`
+	Do                     string `binding:"Required;In(merge,rebase,rebase-merge,squash)"`
+	MergeTitleField        string
+	MergeMessageField      string
+	ForceMerge             *bool `json:"force_merge,omitempty"`
+	MergeWhenChecksSucceed bool
 }
 
 // Validate validates the fields

modules/git/commit.go

@@ -467,6 +467,7 @@ func (c *Commit) GetSubModule(entryname string) (*SubModule, error) {
 }
 
 // GetBranchName gets the closes branch name (as returned by 'git name-rev')
+// FIXME: This get only one branch, but one commit can be part of multiple branches
 func (c *Commit) GetBranchName() (string, error) {
 	data, err := NewCommand("name-rev", c.ID.String()).RunInDirBytes(c.repo.Path)
 	if err != nil {
@@ -477,6 +478,25 @@ func (c *Commit) GetBranchName() (string, error) {
 	return strings.Split(strings.Split(string(data), " ")[1], "~")[0], nil
 }
 
+// GetBranchNames returns all branches a commit is part of
+func (c *Commit) GetBranchNames() (branchNames []string, err error) {
+	data, err := NewCommand("name-rev", c.ID.String()).RunInDirBytes(c.repo.Path)
+	if err != nil {
+		return
+	}
+
+	namesRaw := strings.Split(string(data), "\n")
+	for _, s := range namesRaw {
+		s = strings.TrimSpace(s)
+		if s == "" {
+			continue
+		}
+		branchNames = append(branchNames, strings.Split(strings.Split(s, " ")[1], "~")[0])
+	}
+
+	return
+}
+
 // CommitFileStatus represents status of files in a commit.
 type CommitFileStatus struct {
 	Added    []string

modules/repofiles/commit_status.go

@@ -9,6 +9,7 @@ import (
 
 	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/services/automerge"
 )
 
 // CreateCommitStatus creates a new CommitStatus given a bunch of parameters
@@ -37,5 +38,12 @@ func CreateCommitStatus(repo *models.Repository, creator *models.User, sha strin
 		return fmt.Errorf("NewCommitStatus[repo_id: %d, user_id: %d, sha: %s]: %v", repo.ID, creator.ID, sha, err)
 	}
 
+	if status.State.IsSuccess() {
+		err = automerge.MergeScheduledPullRequest(sha, repo)
+		if err != nil {
+			return fmt.Errorf("MergeScheduledPullRequest[repo_id: %d, user_id: %d, sha: %s]: %v", repo.ID, creator.ID, sha, err)
+		}
+	}
+
 	return nil
 }

options/locale/locale_en-US.ini

@@ -1135,6 +1135,14 @@ pulls.rebase_merge_pull_request = Rebase and Merge
 pulls.rebase_merge_commit_pull_request = Rebase and Merge (--no-ff)
 pulls.squash_merge_pull_request = Squash and Merge
 pulls.require_signed_wont_sign = The branch requires signed commits but this merge will not be signed
+pulls.merge_pull_request_now = Merge Pull Request Now
+pulls.rebase_merge_pull_request_now = Rebase and Merge Now
+pulls.rebase_merge_commit_pull_request_now = Rebase and Merge Now (--no-ff)
+pulls.squash_merge_pull_request_now = Squash and Merge Now
+pulls.merge_pull_request_on_status_success = Merge Pull Request When All Checks Succeed
+pulls.rebase_merge_pull_request_on_status_success = Rebase and Merge When All Checks Succeed
+pulls.rebase_merge_commit_pull_request_on_status_success = Rebase and Merge (--no-ff) When All Checks Succeed
+pulls.squash_merge_pull_request_on_status_success = Squash and Merge When All Checks Succeed
 pulls.invalid_merge_option = You cannot use this merge option for this pull request.
 pulls.merge_conflict = Merge Failed: There was a conflict whilst merging: %[1]s<br>%[2]s<br>Hint: Try a different strategy
 pulls.rebase_conflict = Merge Failed: There was a conflict whilst rebasing commit: %[1]s<br>%[2]s<br>%[3]s<br>Hint:Try a different strategy
@@ -1154,6 +1162,11 @@ pulls.update_not_allowed = You are not allowed to update branch
 pulls.outdated_with_base_branch = This branch is out-of-date with the base branch
 pulls.closed_at = `closed this pull request <a id="%[1]s" href="#%[1]s">%[2]s</a>`
 pulls.reopened_at = `reopened this pull request <a id="%[1]s" href="#%[1]s">%[2]s</a>`
+pulls.merge_on_status_success_success = The pull request was successfully scheduled to merge when all checks succeed.
+pulls.pr_has_pending_merge_on_success = This pull request has been set to auto merge when all checks succeed by %[1]s %[2]s.
+pulls.merge_pull_on_success_cancel = Cancel automatic merge
+pulls.pull_request_not_scheduled = This pull request is not scheduled to auto merge.
+pulls.pull_request_schedule_canceled = This pull request was successfully canceled for auto merge.
 
 milestones.new = New Milestone
 milestones.open_tab = %d Open

routers/repo/issue.go

@@ -1104,6 +1104,13 @@ func ViewIssue(ctx *context.Context) {
 			ctx.ServerError("GetReviewersByIssueID", err)
 			return
 		}
+
+		// Check if there is a pending pr merge
+		ctx.Data["HasPendingPullRequestMerge"], ctx.Data["PendingPullRequestMerge"], err = models.GetScheduledMergeRequestByPullID(pull.ID)
+		if err != nil {
+			ctx.ServerError("GetReviewersByIssueID", err)
+			return
+		}
 	}
 
 	// Get Dependencies

routers/repo/pull.go

@@ -810,6 +810,34 @@ func MergePullRequest(ctx *context.Context, form auth.MergePullRequestForm) {
 		return
 	}
 
+	lastCommitStatus, err := pr.GetLastCommitStatus()
+	if err != nil {
+		return
+	}
+	if form.MergeWhenChecksSucceed && !lastCommitStatus.State.IsSuccess() {
+		err = models.ScheduleAutoMerge(&models.ScheduledPullRequestMerge{
+			PullID:     pr.ID,
+			UserID:     ctx.User.ID,
+			MergeStyle: models.MergeStyle(form.Do),
+			Message:    message,
+		})
+		if err != nil {
+			ctx.Flash.Error(ctx.Tr("repo.issues.dependency.pr_close_blocked"))
+			ctx.Redirect(ctx.Repo.RepoLink + "/pulls/" + com.ToStr(pr.Index))
+			return
+		}
+		ctx.Flash.Success(ctx.Tr("repo.pulls.merge_on_status_success_success"))
+		ctx.Redirect(ctx.Repo.RepoLink + "/pulls/" + com.ToStr(pr.Index))
+		return
+	}
+	// Removing an auto merge pull request is something we can execute whether or not a pull request auto merge was
+	// scheduled before, hece we can remove it without checking for its existence.
+	err = models.RemoveScheduledMergeRequest(&models.ScheduledPullRequestMerge{PullID: pr.ID})
+	if err != nil {
+		ctx.ServerError("RemoveScheduledMergeRequest", err)
+		return
+	}
+
 	if err = pull_service.Merge(pr, ctx.User, ctx.Repo.GitRepo, models.MergeStyle(form.Do), message); err != nil {
 		if models.IsErrInvalidMergeStyle(err) {
 			ctx.Flash.Error(ctx.Tr("repo.pulls.invalid_merge_option"))
@@ -860,6 +888,33 @@ func MergePullRequest(ctx *context.Context, form auth.MergePullRequestForm) {
 	ctx.Redirect(ctx.Repo.RepoLink + "/pulls/" + com.ToStr(pr.Index))
 }
 
+// CancelAutoMergePullRequest cancels a scheduled pr
+func CancelAutoMergePullRequest(ctx *context.Context) {
+	issue := checkPullInfo(ctx)
+	if ctx.Written() {
+		return
+	}
+	pr := issue.PullRequest
+	exists, scheduledInfo, err := models.GetScheduledMergeRequestByPullID(pr.ID)
+	if err != nil {
+		ctx.ServerError("GetScheduledMergeRequestByPullID", err)
+		return
+	}
+	if !exists {
+		ctx.Flash.Error(ctx.Tr("repo.pulls.pull_request_not_scheduled"))
+		ctx.Redirect(ctx.Repo.RepoLink + "/pulls/" + com.ToStr(pr.Index))
+		return
+	}
+	err = models.RemoveScheduledMergeRequest(scheduledInfo)
+	if err != nil {
+		ctx.ServerError("RemoveScheduledMergeRequest", err)
+		return
+	}
+
+	ctx.Flash.Success(ctx.Tr("repo.pulls.pull_request_schedule_canceled"))
+	ctx.Redirect(ctx.Repo.RepoLink + "/pulls/" + com.ToStr(issue.Index))
+}
+
 func stopTimerIfAvailable(user *models.User, issue *models.Issue) error {
 
 	if models.StopwatchExists(user.ID, issue.ID) {

routers/routes/routes.go

@@ -895,6 +895,7 @@ func RegisterRoutes(m *macaron.Macaron) {
 			m.Get(".patch", repo.DownloadPullPatch)
 			m.Get("/commits", context.RepoRef(), repo.ViewPullCommits)
 			m.Post("/merge", context.RepoMustNotBeArchived(), bindIgnErr(auth.MergePullRequestForm{}), repo.MergePullRequest)
+			m.Post("/cancel_auto_merge", context.RepoMustNotBeArchived(), repo.CancelAutoMergePullRequest)
 			m.Post("/update", repo.UpdatePullRequest)
 			m.Post("/cleanup", context.RepoMustNotBeArchived(), context.RepoRef(), repo.CleanUpPullRequest)
 			m.Group("/files", func() {