Change target branch for pull request (#6488)

* Adds functionality to change target branch of created pull requests

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Use const instead of var in JavaScript additions

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Check if branches are equal and if PR already exists before changing target branch

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Make sure to check all commits

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Print error messages for user as error flash message

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Disallow changing target branch of closed or merged pull requests

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Resolve conflicts after merge of upstream/master

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Change order of branch select fields

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Removes duplicate check

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Use ctx.Tr for translations

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Recompile JS

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Use correct translation namespace

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Remove redundant if condition

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Moves most change branch logic into pull service

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Completes comment

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Add Ref to ChangesPayload for logging changed target branches
instead of creating a new struct

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Revert changes to go.mod

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Directly use createComment method

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Return 404 if pull request is not found. Move written check up

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Remove variable declaration

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Return client errors on change pull request target errors

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Return error in commit.HasPreviousCommit

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Adds blank line

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Test patch before persisting new target branch

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Update patch before testing (not working)

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Removes patch calls when changeing pull request target

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Removes unneeded check for base name

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Moves ChangeTargetBranch completely to pull service. Update patch status.

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Set webhook mode after errors were validated

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Update PR in one transaction

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Move logic for check if head is equal with branch to pull model

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Adds missing comment and simplify return

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Adjust CreateComment method call

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

models/error.go

@@ -953,6 +953,22 @@ func (err ErrBranchNameConflict) Error() string {
 	return fmt.Sprintf("branch conflicts with existing branch [name: %s]", err.BranchName)
 }
 
+// ErrBranchesEqual represents an error that branch name conflicts with other branch.
+type ErrBranchesEqual struct {
+	BaseBranchName string
+	HeadBranchName string
+}
+
+// IsErrBranchesEqual checks if an error is an ErrBranchesEqual.
+func IsErrBranchesEqual(err error) bool {
+	_, ok := err.(ErrBranchesEqual)
+	return ok
+}
+
+func (err ErrBranchesEqual) Error() string {
+	return fmt.Sprintf("branches are equal [head: %sm base: %s]", err.HeadBranchName, err.BaseBranchName)
+}
+
 // ErrNotAllowedToMerge represents an error that a branch is protected and the current user is not allowed to modify it.
 type ErrNotAllowedToMerge struct {
 	Reason string
@@ -1090,6 +1106,23 @@ func (err ErrIssueNotExist) Error() string {
 	return fmt.Sprintf("issue does not exist [id: %d, repo_id: %d, index: %d]", err.ID, err.RepoID, err.Index)
 }
 
+// ErrIssueIsClosed represents a "IssueIsClosed" kind of error.
+type ErrIssueIsClosed struct {
+	ID     int64
+	RepoID int64
+	Index  int64
+}
+
+// IsErrIssueIsClosed checks if an error is a ErrIssueNotExist.
+func IsErrIssueIsClosed(err error) bool {
+	_, ok := err.(ErrIssueIsClosed)
+	return ok
+}
+
+func (err ErrIssueIsClosed) Error() string {
+	return fmt.Sprintf("issue is closed [id: %d, repo_id: %d, index: %d]", err.ID, err.RepoID, err.Index)
+}
+
 // ErrIssueLabelTemplateLoad represents a "ErrIssueLabelTemplateLoad" kind of error.
 type ErrIssueLabelTemplateLoad struct {
 	TemplateFile  string
@@ -1326,6 +1359,28 @@ func (err ErrRebaseConflicts) Error() string {
 	return fmt.Sprintf("Rebase Error: %v: Whilst Rebasing: %s\n%s\n%s", err.Err, err.CommitSHA, err.StdErr, err.StdOut)
 }
 
+// ErrPullRequestHasMerged represents a "PullRequestHasMerged"-error
+type ErrPullRequestHasMerged struct {
+	ID         int64
+	IssueID    int64
+	HeadRepoID int64
+	BaseRepoID int64
+	HeadBranch string
+	BaseBranch string
+}
+
+// IsErrPullRequestHasMerged checks if an error is a ErrPullRequestHasMerged.
+func IsErrPullRequestHasMerged(err error) bool {
+	_, ok := err.(ErrPullRequestHasMerged)
+	return ok
+}
+
+// Error does pretty-printing :D
+func (err ErrPullRequestHasMerged) Error() string {
+	return fmt.Sprintf("pull request has merged [id: %d, issue_id: %d, head_repo_id: %d, base_repo_id: %d, head_branch: %s, base_branch: %s]",
+		err.ID, err.IssueID, err.HeadRepoID, err.BaseRepoID, err.HeadBranch, err.BaseBranch)
+}
+
 // _________                                       __
 // \_   ___ \  ____   _____   _____   ____   _____/  |_
 // /    \  \/ /  _ \ /     \ /     \_/ __ \ /    \   __\

models/issue_comment.go

@@ -82,6 +82,8 @@ const (
 	CommentTypeLock
 	// Unlocks a previously locked issue
 	CommentTypeUnlock
+	// Change pull request's target branch
+	CommentTypeChangeTargetBranch
 )
 
 // CommentTag defines comment tag type
@@ -116,6 +118,8 @@ type Comment struct {
 	Assignee         *User `xorm:"-"`
 	OldTitle         string
 	NewTitle         string
+	OldRef           string
+	NewRef           string
 	DependentIssueID int64
 	DependentIssue   *Issue `xorm:"-"`
 
@@ -517,6 +521,8 @@ func createComment(e *xorm.Session, opts *CreateCommentOptions) (_ *Comment, err
 		Content:          opts.Content,
 		OldTitle:         opts.OldTitle,
 		NewTitle:         opts.NewTitle,
+		OldRef:           opts.OldRef,
+		NewRef:           opts.NewRef,
 		DependentIssueID: opts.DependentIssueID,
 		TreePath:         opts.TreePath,
 		ReviewID:         opts.ReviewID,
@@ -673,6 +679,8 @@ type CreateCommentOptions struct {
 	RemovedAssignee  bool
 	OldTitle         string
 	NewTitle         string
+	OldRef           string
+	NewRef           string
 	CommitID         int64
 	CommitSHA        string
 	Patch            string

models/migrations/migrations.go

@@ -280,6 +280,8 @@ var migrations = []Migration{
 	NewMigration("update branch protection for can push and whitelist enable", addBranchProtectionCanPushAndEnableWhitelist),
 	// v112 -> v113
 	NewMigration("remove release attachments which repository deleted", removeAttachmentMissedRepo),
+	// v113 -> v114
+	NewMigration("new feature: change target branch of pull requests", featureChangeTargetBranch),
 }
 
 // Migrate database to current version

models/migrations/v113.go

@@ -0,0 +1,23 @@
+// Copyright 2019 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 (
+	"fmt"
+
+	"xorm.io/xorm"
+)
+
+func featureChangeTargetBranch(x *xorm.Engine) error {
+	type Comment struct {
+		OldRef string
+		NewRef string
+	}
+
+	if err := x.Sync2(new(Comment)); err != nil {
+		return fmt.Errorf("Sync2: %v", err)
+	}
+	return nil
+}

models/pull.go

@@ -664,3 +664,32 @@ func (pr *PullRequest) GetWorkInProgressPrefix() string {
 	}
 	return ""
 }
+
+// IsHeadEqualWithBranch returns if the commits of branchName are available in pull request head
+func (pr *PullRequest) IsHeadEqualWithBranch(branchName string) (bool, error) {
+	var err error
+	if err = pr.GetBaseRepo(); err != nil {
+		return false, err
+	}
+	baseGitRepo, err := git.OpenRepository(pr.BaseRepo.RepoPath())
+	if err != nil {
+		return false, err
+	}
+	baseCommit, err := baseGitRepo.GetBranchCommit(branchName)
+	if err != nil {
+		return false, err
+	}
+
+	if err = pr.GetHeadRepo(); err != nil {
+		return false, err
+	}
+	headGitRepo, err := git.OpenRepository(pr.HeadRepo.RepoPath())
+	if err != nil {
+		return false, err
+	}
+	headCommit, err := headGitRepo.GetBranchCommit(pr.HeadBranch)
+	if err != nil {
+		return false, err
+	}
+	return baseCommit.HasPreviousCommit(headCommit.ID)
+}

modules/git/commit.go

@@ -306,6 +306,27 @@ func (c *Commit) CommitsBefore() (*list.List, error) {
 	return c.repo.getCommitsBefore(c.ID)
 }
 
+// HasPreviousCommit returns true if a given commitHash is contained in commit's parents
+func (c *Commit) HasPreviousCommit(commitHash SHA1) (bool, error) {
+	for i := 0; i < c.ParentCount(); i++ {
+		commit, err := c.Parent(i)
+		if err != nil {
+			return false, err
+		}
+		if commit.ID == commitHash {
+			return true, nil
+		}
+		commitInParentCommit, err := commit.HasPreviousCommit(commitHash)
+		if err != nil {
+			return false, err
+		}
+		if commitInParentCommit {
+			return true, nil
+		}
+	}
+	return false, nil
+}
+
 // CommitsBeforeLimit returns num commits before current revision
 func (c *Commit) CommitsBeforeLimit(num int) (*list.List, error) {
 	return c.repo.getCommitsBeforeLimit(c.ID, num)

modules/notification/base/notifier.go

@@ -34,6 +34,7 @@ type Notifier interface {
 	NotifyMergePullRequest(*models.PullRequest, *models.User, *git.Repository)
 	NotifyPullRequestSynchronized(doer *models.User, pr *models.PullRequest)
 	NotifyPullRequestReview(*models.PullRequest, *models.Review, *models.Comment)
+	NotifyPullRequestChangeTargetBranch(doer *models.User, pr *models.PullRequest, oldBranch string)
 
 	NotifyCreateIssueComment(*models.User, *models.Repository,
 		*models.Issue, *models.Comment)

modules/notification/base/null.go

@@ -50,6 +50,10 @@ func (*NullNotifier) NotifyMergePullRequest(pr *models.PullRequest, doer *models
 func (*NullNotifier) NotifyPullRequestSynchronized(doer *models.User, pr *models.PullRequest) {
 }
 
+// NotifyPullRequestChangeTargetBranch places a place holder function
+func (*NullNotifier) NotifyPullRequestChangeTargetBranch(doer *models.User, pr *models.PullRequest, oldBranch string) {
+}
+
 // NotifyUpdateComment places a place holder function
 func (*NullNotifier) NotifyUpdateComment(doer *models.User, c *models.Comment, oldContent string) {
 }

modules/notification/notification.go

@@ -87,6 +87,13 @@ func NotifyPullRequestReview(pr *models.PullRequest, review *models.Review, comm
 	}
 }
 
+// NotifyPullRequestChangeTargetBranch notifies when a pull request's target branch was changed
+func NotifyPullRequestChangeTargetBranch(doer *models.User, pr *models.PullRequest, oldBranch string) {
+	for _, notifier := range notifiers {
+		notifier.NotifyPullRequestChangeTargetBranch(doer, pr, oldBranch)
+	}
+}
+
 // NotifyUpdateComment notifies update comment to notifiers
 func NotifyUpdateComment(doer *models.User, c *models.Comment, oldContent string) {
 	for _, notifier := range notifiers {

modules/notification/webhook/webhook.go

@@ -559,6 +559,37 @@ func (*webhookNotifier) NotifyMergePullRequest(pr *models.PullRequest, doer *mod
 	}
 }
 
+func (m *webhookNotifier) NotifyPullRequestChangeTargetBranch(doer *models.User, pr *models.PullRequest, oldBranch string) {
+	issue := pr.Issue
+	if !issue.IsPull {
+		return
+	}
+	var err error
+
+	if err = issue.LoadPullRequest(); err != nil {
+		log.Error("LoadPullRequest failed: %v", err)
+		return
+	}
+	issue.PullRequest.Issue = issue
+	mode, _ := models.AccessLevel(issue.Poster, issue.Repo)
+	err = webhook_module.PrepareWebhooks(issue.Repo, models.HookEventPullRequest, &api.PullRequestPayload{
+		Action: api.HookIssueEdited,
+		Index:  issue.Index,
+		Changes: &api.ChangesPayload{
+			Ref: &api.ChangesFromPayload{
+				From: oldBranch,
+			},
+		},
+		PullRequest: issue.PullRequest.APIFormat(),
+		Repository:  issue.Repo.APIFormat(mode),
+		Sender:      doer.APIFormat(),
+	})
+
+	if err != nil {
+		log.Error("PrepareWebhooks [is_pull: %v]: %v", issue.IsPull, err)
+	}
+}
+
 func (m *webhookNotifier) NotifyPullRequestReview(pr *models.PullRequest, review *models.Review, comment *models.Comment) {
 	var reviewHookType models.HookEventType
 

modules/structs/hook.go

@@ -398,10 +398,11 @@ type ChangesFromPayload struct {
 	From string `json:"from"`
 }
 
-// ChangesPayload FIXME
+// ChangesPayload represents the payload information of issue change
 type ChangesPayload struct {
 	Title *ChangesFromPayload `json:"title,omitempty"`
 	Body  *ChangesFromPayload `json:"body,omitempty"`
+	Ref   *ChangesFromPayload `json:"ref,omitempty"`
 }
 
 // __________      .__  .__    __________                                     __

options/locale/locale_en-US.ini

@@ -1033,15 +1033,17 @@ pulls.no_results = No results found.
 pulls.nothing_to_compare = These branches are equal. There is no need to create a pull request.
 pulls.has_pull_request = `A pull request between these branches already exists: <a href="%[1]s/pulls/%[3]d">%[2]s#%[3]d</a>`
 pulls.create = Create Pull Request
-pulls.title_desc = wants to merge %[1]d commits from <code>%[2]s</code> into <code>%[3]s</code>
+pulls.title_desc = wants to merge %[1]d commits from <code>%[2]s</code> into <code id="branch_target">%[3]s</code>
 pulls.merged_title_desc = merged %[1]d commits from <code>%[2]s</code> into <code>%[3]s</code> %[4]s
+pulls.change_target_branch_at = `changed target branch from <b>%s</b> to <b>%s</b> %s`
 pulls.tab_conversation = Conversation
 pulls.tab_commits = Commits
 pulls.tab_files = Files Changed
 pulls.reopen_to_merge = Please reopen this pull request to perform a merge.
 pulls.cant_reopen_deleted_branch = This pull request cannot be reopened because the branch was deleted.
 pulls.merged = Merged
 pulls.merged_as = The pull request has been merged as <a rel="nofollow" class="ui sha" href="%[1]s"><code>%[2]s</code></a>.
+pulls.is_closed = The pull request has been closed.
 pulls.has_merged = The pull request has been merged.
 pulls.title_wip_desc = `<a href="#">Start the title with <strong>%s</strong></a> to prevent the pull request from being merged accidentally.`
 pulls.cannot_merge_work_in_progress = This pull request is marked as a work in progress. Remove the <strong>%s</strong> prefix from the title when it's ready

routers/repo/issue.go

@@ -605,6 +605,19 @@ func commentTag(repo *models.Repository, poster *models.User, issue *models.Issu
 	return models.CommentTagNone, nil
 }
 
+func getBranchData(ctx *context.Context, issue *models.Issue) {
+	ctx.Data["BaseBranch"] = nil
+	ctx.Data["HeadBranch"] = nil
+	ctx.Data["HeadUserName"] = nil
+	ctx.Data["BaseName"] = ctx.Repo.Repository.OwnerName
+	if issue.IsPull {
+		pull := issue.PullRequest
+		ctx.Data["BaseBranch"] = pull.BaseBranch
+		ctx.Data["HeadBranch"] = pull.HeadBranch
+		ctx.Data["HeadUserName"] = pull.MustHeadUserName()
+	}
+}
+
 // ViewIssue render issue view page
 func ViewIssue(ctx *context.Context) {
 	if ctx.Params(":type") == "issues" {
@@ -885,6 +898,7 @@ func ViewIssue(ctx *context.Context) {
 		}
 	}
 
+	getBranchData(ctx, issue)
 	if issue.IsPull {
 		pull := issue.PullRequest
 		pull.Issue = issue