Add apply-patch, basic revert and cherry-pick functionality (#17902)

This code adds a simple endpoint to apply patches to repositories and
branches on gitea. This is then used along with the conflicting checking
code in #18004 to provide a basic implementation of cherry-pick revert.

Now because the buttons necessary for cherry-pick and revert have 
required us to create a dropdown next to the Browse Source button
I've also implemented Create Branch and Create Tag operations.

Fix #3880 
Fix #17986 

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

modules/git/diff.go

@@ -32,6 +32,21 @@ func GetRawDiff(ctx context.Context, repoPath, commitID string, diffType RawDiff
 	return GetRawDiffForFile(ctx, repoPath, "", commitID, diffType, "", writer)
 }
 
+// GetReverseRawDiff dumps the reverse diff results of repository in given commit ID to io.Writer.
+func GetReverseRawDiff(ctx context.Context, repoPath, commitID string, writer io.Writer) error {
+	stderr := new(bytes.Buffer)
+	cmd := NewCommand(ctx, "show", "--pretty=format:revert %H%n", "-R", commitID)
+	if err := cmd.RunWithContext(&RunContext{
+		Timeout: -1,
+		Dir:     repoPath,
+		Stdout:  writer,
+		Stderr:  stderr,
+	}); err != nil {
+		return fmt.Errorf("Run: %v - %s", err, stderr)
+	}
+	return nil
+}
+
 // GetRawDiffForFile dumps diff results of file in given commit ID to io.Writer.
 func GetRawDiffForFile(ctx context.Context, repoPath, startCommit, endCommit string, diffType RawDiffType, file string, writer io.Writer) error {
 	repo, closer, err := RepositoryFromContextOrOpen(ctx, repoPath)
@@ -221,8 +236,7 @@ func CutDiffAroundLine(originalDiff io.Reader, line int64, old bool, numbersOfLi
 			}
 		}
 	}
-	err := scanner.Err()
+	if err := scanner.Err(); err != nil {
-	if err != nil {
 		return "", err
 	}
 

modules/structs/repo_file.go

@@ -50,6 +50,14 @@ type UpdateFileOptions struct {
 	FromPath string `json:"from_path" binding:"MaxSize(500)"`
 }
 
+// ApplyDiffPatchFileOptions options for applying a diff patch
+// Note: `author` and `committer` are optional (if only one is given, it will be used for the other, otherwise the authenticated user will be used)
+type ApplyDiffPatchFileOptions struct {
+	DeleteFileOptions
+	// required: true
+	Content string `json:"content"`
+}
+
 // FileLinksResponse contains the links for a repo's file
 type FileLinksResponse struct {
 	Self    *string `json:"self"`

options/locale/locale_en-US.ini

@@ -1075,6 +1075,10 @@ editor.add_tmpl = Add '<filename>'
 editor.add = Add '%s'
 editor.update = Update '%s'
 editor.delete = Delete '%s'
+editor.patch = Apply Patch
+editor.patching = Patching:
+editor.fail_to_apply_patch = Unable to apply patch '%s'
+editor.new_patch = New Patch
 editor.commit_message_desc = Add an optional extended description…
 editor.signoff_desc = Add a Signed-off-by trailer by the committer at the end of the commit log message.
 editor.commit_directly_to_this_branch = Commit directly to the <strong class="branch-name">%s</strong> branch.
@@ -1110,6 +1114,8 @@ editor.cannot_commit_to_protected_branch = Cannot commit to protected branch '%s
 editor.no_commit_to_branch = Unable to commit directly to branch because:
 editor.user_no_push_to_branch = User cannot push to branch
 editor.require_signed_commit = Branch requires a signed commit
+editor.cherry_pick = Cherry-pick %s onto:
+editor.revert = Revert %s onto:
 
 commits.desc = Browse source code change history.
 commits.commits = Commits
@@ -1130,6 +1136,14 @@ commits.signed_by_untrusted_user_unmatched = Signed by untrusted user who does n
 commits.gpg_key_id = GPG Key ID
 commits.ssh_key_fingerprint = SSH Key Fingerprint
 
+commit.actions = Actions
+commit.revert = Revert
+commit.revert-header = Revert: %s
+commit.revert-content = Select branch to revert onto:
+commit.cherry-pick = Cherry-pick
+commit.cherry-pick-header = Cherry-pick: %s
+commit.cherry-pick-content = Select branch to cherry-pick onto:
+
 ext_issues = Access to External Issues
 ext_issues.desc = Link to an external issue tracker.
 
@@ -2215,11 +2229,16 @@ branch.included_desc = This branch is part of the default branch
 branch.included = Included
 branch.create_new_branch = Create branch from branch:
 branch.confirm_create_branch = Create branch
+branch.create_branch_operation = Create branch
 branch.new_branch = Create new branch
 branch.new_branch_from = Create new branch from '%s'
 branch.renamed = Branch %s was renamed to %s.
 
 tag.create_tag = Create tag <strong>%s</strong>
+tag.create_tag_operation = Create tag
+tag.confirm_create_tag = Create tag
+tag.create_tag_from = Create new tag from '%s'
+
 tag.create_success = Tag '%s' has been created.
 
 topic.manage_topics = Manage Topics

routers/api/v1/api.go

@@ -975,6 +975,7 @@ func Routes(sessioner func(http.Handler) http.Handler) *web.Route {
 					m.Get("/tags/{sha}", context.RepoRefForAPI, repo.GetAnnotatedTag)
 					m.Get("/notes/{sha}", repo.GetNote)
 				}, reqRepoReader(unit.TypeCode))
+				m.Post("/diffpatch", reqRepoWriter(unit.TypeCode), reqToken(), bind(api.ApplyDiffPatchFileOptions{}), repo.ApplyDiffPatch)
 				m.Group("/contents", func() {
 					m.Get("", repo.GetContentsList)
 					m.Get("/*", repo.GetContents)

routers/api/v1/repo/patch.go

@@ -0,0 +1,107 @@
+// 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 repo
+
+import (
+	"net/http"
+	"time"
+
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/context"
+	"code.gitea.io/gitea/modules/git"
+	api "code.gitea.io/gitea/modules/structs"
+	"code.gitea.io/gitea/modules/web"
+	"code.gitea.io/gitea/services/repository/files"
+)
+
+// ApplyDiffPatch handles API call for applying a patch
+func ApplyDiffPatch(ctx *context.APIContext) {
+	// swagger:operation POST /repos/{owner}/{repo}/diffpatch repository repoApplyDiffPatch
+	// ---
+	// summary: Apply diff patch to repository
+	// consumes:
+	// - application/json
+	// produces:
+	// - application/json
+	// parameters:
+	// - name: owner
+	//   in: path
+	//   description: owner of the repo
+	//   type: string
+	//   required: true
+	// - name: repo
+	//   in: path
+	//   description: name of the repo
+	//   type: string
+	//   required: true
+	// - name: body
+	//   in: body
+	//   required: true
+	//   schema:
+	//     "$ref": "#/definitions/UpdateFileOptions"
+	// responses:
+	//   "200":
+	//     "$ref": "#/responses/FileResponse"
+	apiOpts := web.GetForm(ctx).(*api.ApplyDiffPatchFileOptions)
+
+	opts := &files.ApplyDiffPatchOptions{
+		Content:   apiOpts.Content,
+		SHA:       apiOpts.SHA,
+		Message:   apiOpts.Message,
+		OldBranch: apiOpts.BranchName,
+		NewBranch: apiOpts.NewBranchName,
+		Committer: &files.IdentityOptions{
+			Name:  apiOpts.Committer.Name,
+			Email: apiOpts.Committer.Email,
+		},
+		Author: &files.IdentityOptions{
+			Name:  apiOpts.Author.Name,
+			Email: apiOpts.Author.Email,
+		},
+		Dates: &files.CommitDateOptions{
+			Author:    apiOpts.Dates.Author,
+			Committer: apiOpts.Dates.Committer,
+		},
+		Signoff: apiOpts.Signoff,
+	}
+	if opts.Dates.Author.IsZero() {
+		opts.Dates.Author = time.Now()
+	}
+	if opts.Dates.Committer.IsZero() {
+		opts.Dates.Committer = time.Now()
+	}
+
+	if opts.Message == "" {
+		opts.Message = "apply-patch"
+	}
+
+	if !canWriteFiles(ctx.Repo) {
+		ctx.Error(http.StatusInternalServerError, "ApplyPatch", models.ErrUserDoesNotHaveAccessToRepo{
+			UserID:   ctx.User.ID,
+			RepoName: ctx.Repo.Repository.LowerName,
+		})
+		return
+	}
+
+	fileResponse, err := files.ApplyDiffPatch(ctx, ctx.Repo.Repository, ctx.User, opts)
+	if err != nil {
+		if models.IsErrUserCannotCommit(err) || models.IsErrFilePathProtected(err) {
+			ctx.Error(http.StatusForbidden, "Access", err)
+			return
+		}
+		if models.IsErrBranchAlreadyExists(err) || models.IsErrFilenameInvalid(err) || models.IsErrSHADoesNotMatch(err) ||
+			models.IsErrFilePathInvalid(err) || models.IsErrRepoFileAlreadyExists(err) {
+			ctx.Error(http.StatusUnprocessableEntity, "Invalid", err)
+			return
+		}
+		if models.IsErrBranchDoesNotExist(err) || git.IsErrBranchNotExist(err) {
+			ctx.Error(http.StatusNotFound, "BranchDoesNotExist", err)
+			return
+		}
+		ctx.Error(http.StatusInternalServerError, "ApplyPatch", err)
+	} else {
+		ctx.JSON(http.StatusCreated, fileResponse)
+	}
+}

routers/web/repo/cherry_pick.go

@@ -0,0 +1,189 @@
+// 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 repo
+
+import (
+	"bytes"
+	"errors"
+	"strings"
+
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/models/unit"
+	"code.gitea.io/gitea/modules/base"
+	"code.gitea.io/gitea/modules/context"
+	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/util"
+	"code.gitea.io/gitea/modules/web"
+	"code.gitea.io/gitea/services/forms"
+	"code.gitea.io/gitea/services/repository/files"
+)
+
+var tplCherryPick base.TplName = "repo/editor/cherry_pick"
+
+// CherryPick handles cherrypick GETs
+func CherryPick(ctx *context.Context) {
+	ctx.Data["SHA"] = ctx.Params(":sha")
+	cherryPickCommit, err := ctx.Repo.GitRepo.GetCommit(ctx.Params(":sha"))
+	if err != nil {
+		if git.IsErrNotExist(err) {
+			ctx.NotFound("Missing Commit", err)
+			return
+		}
+		ctx.ServerError("GetCommit", err)
+		return
+	}
+
+	if ctx.FormString("cherry-pick-type") == "revert" {
+		ctx.Data["CherryPickType"] = "revert"
+		ctx.Data["commit_summary"] = "revert " + ctx.Params(":sha")
+		ctx.Data["commit_message"] = "revert " + cherryPickCommit.Message()
+	} else {
+		ctx.Data["CherryPickType"] = "cherry-pick"
+		splits := strings.SplitN(cherryPickCommit.Message(), "\n", 2)
+		ctx.Data["commit_summary"] = splits[0]
+		ctx.Data["commit_message"] = splits[1]
+	}
+
+	ctx.Data["RequireHighlightJS"] = true
+
+	canCommit := renderCommitRights(ctx)
+	ctx.Data["TreePath"] = "patch"
+
+	if canCommit {
+		ctx.Data["commit_choice"] = frmCommitChoiceDirect
+	} else {
+		ctx.Data["commit_choice"] = frmCommitChoiceNewBranch
+	}
+	ctx.Data["new_branch_name"] = GetUniquePatchBranchName(ctx)
+	ctx.Data["last_commit"] = ctx.Repo.CommitID
+	ctx.Data["LineWrapExtensions"] = strings.Join(setting.Repository.Editor.LineWrapExtensions, ",")
+	ctx.Data["BranchLink"] = ctx.Repo.RepoLink + "/src/" + ctx.Repo.BranchNameSubURL()
+
+	ctx.HTML(200, tplCherryPick)
+}
+
+// CherryPickPost handles cherrypick POSTs
+func CherryPickPost(ctx *context.Context) {
+	form := web.GetForm(ctx).(*forms.CherryPickForm)
+
+	sha := ctx.Params(":sha")
+	ctx.Data["SHA"] = sha
+	if form.Revert {
+		ctx.Data["CherryPickType"] = "revert"
+	} else {
+		ctx.Data["CherryPickType"] = "cherry-pick"
+	}
+
+	ctx.Data["RequireHighlightJS"] = true
+	canCommit := renderCommitRights(ctx)
+	branchName := ctx.Repo.BranchName
+	if form.CommitChoice == frmCommitChoiceNewBranch {
+		branchName = form.NewBranchName
+	}
+	ctx.Data["commit_summary"] = form.CommitSummary
+	ctx.Data["commit_message"] = form.CommitMessage
+	ctx.Data["commit_choice"] = form.CommitChoice
+	ctx.Data["new_branch_name"] = form.NewBranchName
+	ctx.Data["last_commit"] = ctx.Repo.CommitID
+	ctx.Data["LineWrapExtensions"] = strings.Join(setting.Repository.Editor.LineWrapExtensions, ",")
+	ctx.Data["BranchLink"] = ctx.Repo.RepoLink + "/src/" + ctx.Repo.BranchNameSubURL()
+
+	if ctx.HasError() {
+		ctx.HTML(200, tplCherryPick)
+		return
+	}
+
+	// Cannot commit to a an existing branch if user doesn't have rights
+	if branchName == ctx.Repo.BranchName && !canCommit {
+		ctx.Data["Err_NewBranchName"] = true
+		ctx.Data["commit_choice"] = frmCommitChoiceNewBranch
+		ctx.RenderWithErr(ctx.Tr("repo.editor.cannot_commit_to_protected_branch", branchName), tplCherryPick, &form)
+		return
+	}
+
+	message := strings.TrimSpace(form.CommitSummary)
+	if message == "" {
+		if form.Revert {
+			message = ctx.Tr("repo.commit.revert-header", sha)
+		} else {
+			message = ctx.Tr("repo.commit.cherry-pick-header", sha)
+		}
+	}
+
+	form.CommitMessage = strings.TrimSpace(form.CommitMessage)
+	if len(form.CommitMessage) > 0 {
+		message += "\n\n" + form.CommitMessage
+	}
+
+	opts := &files.ApplyDiffPatchOptions{
+		LastCommitID: form.LastCommit,
+		OldBranch:    ctx.Repo.BranchName,
+		NewBranch:    branchName,
+		Message:      message,
+	}
+
+	// First lets try the simple plain read-tree -m approach
+	opts.Content = sha
+	if _, err := files.CherryPick(ctx, ctx.Repo.Repository, ctx.User, form.Revert, opts); err != nil {
+		if models.IsErrBranchAlreadyExists(err) {
+			// User has specified a branch that already exists
+			branchErr := err.(models.ErrBranchAlreadyExists)
+			ctx.Data["Err_NewBranchName"] = true
+			ctx.RenderWithErr(ctx.Tr("repo.editor.branch_already_exists", branchErr.BranchName), tplCherryPick, &form)
+			return
+		} else if models.IsErrCommitIDDoesNotMatch(err) {
+			ctx.RenderWithErr(ctx.Tr("repo.editor.file_changed_while_editing", ctx.Repo.RepoLink+"/compare/"+form.LastCommit+"..."+ctx.Repo.CommitID), tplPatchFile, &form)
+			return
+		}
+		// Drop through to the apply technique
+
+		buf := &bytes.Buffer{}
+		if form.Revert {
+			if err := git.GetReverseRawDiff(ctx, ctx.Repo.Repository.RepoPath(), sha, buf); err != nil {
+				if git.IsErrNotExist(err) {
+					ctx.NotFound("GetRawDiff", errors.New("commit "+ctx.Params(":sha")+" does not exist."))
+					return
+				}
+				ctx.ServerError("GetRawDiff", err)
+				return
+			}
+		} else {
+			if err := git.GetRawDiff(ctx, ctx.Repo.Repository.RepoPath(), sha, git.RawDiffType("patch"), buf); err != nil {
+				if git.IsErrNotExist(err) {
+					ctx.NotFound("GetRawDiff", errors.New("commit "+ctx.Params(":sha")+" does not exist."))
+					return
+				}
+				ctx.ServerError("GetRawDiff", err)
+				return
+			}
+		}
+
+		opts.Content = buf.String()
+		ctx.Data["FileContent"] = opts.Content
+
+		if _, err := files.ApplyDiffPatch(ctx, ctx.Repo.Repository, ctx.User, opts); err != nil {
+			if models.IsErrBranchAlreadyExists(err) {
+				// User has specified a branch that already exists
+				branchErr := err.(models.ErrBranchAlreadyExists)
+				ctx.Data["Err_NewBranchName"] = true
+				ctx.RenderWithErr(ctx.Tr("repo.editor.branch_already_exists", branchErr.BranchName), tplCherryPick, &form)
+				return
+			} else if models.IsErrCommitIDDoesNotMatch(err) {
+				ctx.RenderWithErr(ctx.Tr("repo.editor.file_changed_while_editing", ctx.Repo.RepoLink+"/compare/"+form.LastCommit+"..."+ctx.Repo.CommitID), tplPatchFile, &form)
+				return
+			} else {
+				ctx.RenderWithErr(ctx.Tr("repo.editor.fail_to_apply_patch", err), tplPatchFile, &form)
+				return
+			}
+		}
+	}
+
+	if form.CommitChoice == frmCommitChoiceNewBranch && ctx.Repo.Repository.UnitEnabled(unit.TypePullRequests) {
+		ctx.Redirect(ctx.Repo.RepoLink + "/compare/" + util.PathEscapeSegments(ctx.Repo.BranchName) + "..." + util.PathEscapeSegments(form.NewBranchName))
+	} else {
+		ctx.Redirect(ctx.Repo.RepoLink + "/src/branch/" + util.PathEscapeSegments(branchName))
+	}
+}

routers/web/repo/patch.go

@@ -0,0 +1,120 @@
+// 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 repo
+
+import (
+	"strings"
+
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/models/unit"
+	"code.gitea.io/gitea/modules/base"
+	"code.gitea.io/gitea/modules/context"
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/util"
+	"code.gitea.io/gitea/modules/web"
+	"code.gitea.io/gitea/services/forms"
+	"code.gitea.io/gitea/services/repository/files"
+)
+
+const (
+	tplPatchFile base.TplName = "repo/editor/patch"
+)
+
+// NewDiffPatch render create patch page
+func NewDiffPatch(ctx *context.Context) {
+	ctx.Data["RequireHighlightJS"] = true
+
+	canCommit := renderCommitRights(ctx)
+
+	ctx.Data["TreePath"] = "patch"
+
+	ctx.Data["commit_summary"] = ""
+	ctx.Data["commit_message"] = ""
+	if canCommit {
+		ctx.Data["commit_choice"] = frmCommitChoiceDirect
+	} else {
+		ctx.Data["commit_choice"] = frmCommitChoiceNewBranch
+	}
+	ctx.Data["new_branch_name"] = GetUniquePatchBranchName(ctx)
+	ctx.Data["last_commit"] = ctx.Repo.CommitID
+	ctx.Data["LineWrapExtensions"] = strings.Join(setting.Repository.Editor.LineWrapExtensions, ",")
+	ctx.Data["BranchLink"] = ctx.Repo.RepoLink + "/src/" + ctx.Repo.BranchNameSubURL()
+
+	ctx.HTML(200, tplPatchFile)
+}
+
+// NewDiffPatchPost response for sending patch page
+func NewDiffPatchPost(ctx *context.Context) {
+	form := web.GetForm(ctx).(*forms.EditRepoFileForm)
+
+	canCommit := renderCommitRights(ctx)
+	branchName := ctx.Repo.BranchName
+	if form.CommitChoice == frmCommitChoiceNewBranch {
+		branchName = form.NewBranchName
+	}
+	ctx.Data["RequireHighlightJS"] = true
+	ctx.Data["TreePath"] = "patch"
+	ctx.Data["BranchLink"] = ctx.Repo.RepoLink + "/src/" + ctx.Repo.BranchNameSubURL()
+	ctx.Data["FileContent"] = form.Content
+	ctx.Data["commit_summary"] = form.CommitSummary
+	ctx.Data["commit_message"] = form.CommitMessage
+	ctx.Data["commit_choice"] = form.CommitChoice
+	ctx.Data["new_branch_name"] = form.NewBranchName
+	ctx.Data["last_commit"] = ctx.Repo.CommitID
+	ctx.Data["LineWrapExtensions"] = strings.Join(setting.Repository.Editor.LineWrapExtensions, ",")
+
+	if ctx.HasError() {
+		ctx.HTML(200, tplPatchFile)
+		return
+	}
+
+	// Cannot commit to a an existing branch if user doesn't have rights
+	if branchName == ctx.Repo.BranchName && !canCommit {
+		ctx.Data["Err_NewBranchName"] = true
+		ctx.Data["commit_choice"] = frmCommitChoiceNewBranch
+		ctx.RenderWithErr(ctx.Tr("repo.editor.cannot_commit_to_protected_branch", branchName), tplEditFile, &form)
+		return
+	}
+
+	// CommitSummary is optional in the web form, if empty, give it a default message based on add or update
+	// `message` will be both the summary and message combined
+	message := strings.TrimSpace(form.CommitSummary)
+	if len(message) == 0 {
+		message = ctx.Tr("repo.editor.patch")
+	}
+
+	form.CommitMessage = strings.TrimSpace(form.CommitMessage)
+	if len(form.CommitMessage) > 0 {
+		message += "\n\n" + form.CommitMessage
+	}
+
+	if _, err := files.ApplyDiffPatch(ctx, ctx.Repo.Repository, ctx.User, &files.ApplyDiffPatchOptions{
+		LastCommitID: form.LastCommit,
+		OldBranch:    ctx.Repo.BranchName,
+		NewBranch:    branchName,
+		Message:      message,
+		Content:      strings.ReplaceAll(form.Content, "\r", ""),
+	}); err != nil {
+		if models.IsErrBranchAlreadyExists(err) {
+			// User has specified a branch that already exists
+			branchErr := err.(models.ErrBranchAlreadyExists)
+			ctx.Data["Err_NewBranchName"] = true
+			ctx.RenderWithErr(ctx.Tr("repo.editor.branch_already_exists", branchErr.BranchName), tplEditFile, &form)
+			return
+		} else if models.IsErrCommitIDDoesNotMatch(err) {
+			ctx.RenderWithErr(ctx.Tr("repo.editor.file_changed_while_editing", ctx.Repo.RepoLink+"/compare/"+form.LastCommit+"..."+ctx.Repo.CommitID), tplPatchFile, &form)
+			return
+		} else {
+			ctx.RenderWithErr(ctx.Tr("repo.editor.fail_to_apply_patch", err), tplPatchFile, &form)
+			return
+		}
+	}
+
+	if form.CommitChoice == frmCommitChoiceNewBranch && ctx.Repo.Repository.UnitEnabled(unit.TypePullRequests) {
+		ctx.Redirect(ctx.Repo.RepoLink + "/compare/" + util.PathEscapeSegments(ctx.Repo.BranchName) + "..." + util.PathEscapeSegments(form.NewBranchName))
+	} else {
+		ctx.Redirect(ctx.Repo.RepoLink + "/src/branch/" + util.PathEscapeSegments(branchName) + "/" + util.PathEscapeSegments(form.TreePath))
+	}
+}

routers/web/web.go

@@ -808,6 +808,10 @@ func RegisterRoutes(m *web.Route) {
 				m.Combo("/_upload/*", repo.MustBeAbleToUpload).
 					Get(repo.UploadFile).
 					Post(bindIgnErr(forms.UploadRepoFileForm{}), repo.UploadFilePost)
+				m.Combo("/_diffpatch/*").Get(repo.NewDiffPatch).
+					Post(bindIgnErr(forms.EditRepoFileForm{}), repo.NewDiffPatchPost)
+				m.Combo("/_cherrypick/{sha:([a-f0-9]{7,40})}/*").Get(repo.CherryPick).
+					Post(bindIgnErr(forms.CherryPickForm{}), repo.CherryPickPost)
 			}, context.RepoRefByType(context.RepoRefBranch), repo.MustBeEditable)
 			m.Group("", func() {
 				m.Post("/upload-file", repo.UploadFileToServer)
@@ -1029,6 +1033,7 @@ func RegisterRoutes(m *web.Route) {
 		m.Group("", func() {
 			m.Get("/graph", repo.Graph)
 			m.Get("/commit/{sha:([a-f0-9]{7,40})$}", repo.SetEditorconfigIfExists, repo.SetDiffViewStyle, repo.SetWhitespaceBehavior, repo.Diff)
+			m.Get("/cherry-pick/{sha:([a-f0-9]{7,40})$}", repo.SetEditorconfigIfExists, repo.CherryPick)
 		}, repo.MustBeNotEmpty, context.RepoRef(), reqRepoCodeReader)
 
 		m.Group("/src", func() {

services/forms/repo_form.go

@@ -754,6 +754,30 @@ func (f *EditPreviewDiffForm) Validate(req *http.Request, errs binding.Errors) b
 	return middleware.Validate(errs, ctx.Data, f, ctx.Locale)
 }
 
+// _________ .__                                 __________.__        __
+// \_   ___ \|  |__   __________________ ___.__. \______   \__| ____ |  | __
+// /    \  \/|  |  \_/ __ \_  __ \_  __ <   |  |  |     ___/  |/ ___\|  |/ /
+// \     \___|   Y  \  ___/|  | \/|  | \/\___  |  |    |   |  \  \___|    <
+//  \______  /___|  /\___  >__|   |__|   / ____|  |____|   |__|\___  >__|_ \
+//         \/     \/     \/              \/                        \/     \/
+
+// CherryPickForm form for changing repository file
+type CherryPickForm struct {
+	CommitSummary string `binding:"MaxSize(100)"`
+	CommitMessage string
+	CommitChoice  string `binding:"Required;MaxSize(50)"`
+	NewBranchName string `binding:"GitRefName;MaxSize(100)"`
+	LastCommit    string
+	Revert        bool
+	Signoff       bool
+}
+
+// Validate validates the fields
+func (f *CherryPickForm) Validate(req *http.Request, errs binding.Errors) binding.Errors {
+	ctx := context.GetContext(req)
+	return middleware.Validate(errs, ctx.Data, f, ctx.Locale)
+}
+
 //  ____ ___        .__                    .___
 // |    |   \______ |  |   _________     __| _/
 // |    |   /\____ \|  |  /  _ \__  \   / __ |

services/pull/patch.go

@@ -87,7 +87,7 @@ func TestPatch(pr *models.PullRequest) error {
 	pr.MergeBase = strings.TrimSpace(pr.MergeBase)
 
 	// 2. Check for conflicts
-	if conflicts, err := checkConflicts(pr, gitRepo, tmpBasePath); err != nil || conflicts || pr.Status == models.PullRequestStatusEmpty {
+	if conflicts, err := checkConflicts(ctx, pr, gitRepo, tmpBasePath); err != nil || conflicts || pr.Status == models.PullRequestStatusEmpty {
 		return err
 	}
 
@@ -217,19 +217,20 @@ func attemptMerge(ctx context.Context, file *unmergedFile, tmpBasePath string, g
 	return nil
 }
 
-func checkConflicts(pr *models.PullRequest, gitRepo *git.Repository, tmpBasePath string) (bool, error) {
+// AttemptThreeWayMerge will attempt to three way merge using git read-tree and then follow the git merge-one-file algorithm to attempt to resolve basic conflicts
-	ctx, cancel, finished := process.GetManager().AddContext(graceful.GetManager().HammerContext(), fmt.Sprintf("checkConflicts: pr[%d] %s/%s#%d", pr.ID, pr.BaseRepo.OwnerName, pr.BaseRepo.Name, pr.Index))
+func AttemptThreeWayMerge(ctx context.Context, gitPath string, gitRepo *git.Repository, base, ours, theirs, description string) (bool, []string, error) {
-	defer finished()
+	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
 
 	// First we use read-tree to do a simple three-way merge
-	if _, err := git.NewCommand(ctx, "read-tree", "-m", pr.MergeBase, "base", "tracking").RunInDir(tmpBasePath); err != nil {
+	if _, err := git.NewCommand(ctx, "read-tree", "-m", base, ours, theirs).RunInDir(gitPath); err != nil {
 		log.Error("Unable to run read-tree -m! Error: %v", err)
-		return false, fmt.Errorf("unable to run read-tree -m! Error: %v", err)
+		return false, nil, fmt.Errorf("unable to run read-tree -m! Error: %v", err)
 	}
 
 	// Then we use git ls-files -u to list the unmerged files and collate the triples in unmergedfiles
 	unmerged := make(chan *unmergedFile)
-	go unmergedFiles(ctx, tmpBasePath, unmerged)
+	go unmergedFiles(ctx, gitPath, unmerged)
 
 	defer func() {
 		cancel()
@@ -239,8 +240,8 @@ func checkConflicts(pr *models.PullRequest, gitRepo *git.Repository, tmpBasePath
 	}()
 
 	numberOfConflicts := 0
-	pr.ConflictedFiles = make([]string, 0, 5)
 	conflict := false
+	conflictedFiles := make([]string, 0, 5)
 
 	for file := range unmerged {
 		if file == nil {
@@ -248,23 +249,33 @@ func checkConflicts(pr *models.PullRequest, gitRepo *git.Repository, tmpBasePath
 		}
 		if file.err != nil {
 			cancel()
-			return false, file.err
+			return false, nil, file.err
 		}
 
 		// OK now we have the unmerged file triplet attempt to merge it
-		if err := attemptMerge(ctx, file, tmpBasePath, gitRepo); err != nil {
+		if err := attemptMerge(ctx, file, gitPath, gitRepo); err != nil {
 			if conflictErr, ok := err.(*errMergeConflict); ok {
-				log.Trace("Conflict: %s in PR[%d] %s/%s#%d", conflictErr.filename, pr.ID, pr.BaseRepo.OwnerName, pr.BaseRepo.Name, pr.Index)
+				log.Trace("Conflict: %s in %s", conflictErr.filename, description)
 				conflict = true
 				if numberOfConflicts < 10 {
-					pr.ConflictedFiles = append(pr.ConflictedFiles, conflictErr.filename)
+					conflictedFiles = append(conflictedFiles, conflictErr.filename)
 				}
 				numberOfConflicts++
 				continue
 			}
-			return false, err
+			return false, nil, err
 		}
 	}
+	return conflict, conflictedFiles, nil
+}
+
+func checkConflicts(ctx context.Context, pr *models.PullRequest, gitRepo *git.Repository, tmpBasePath string) (bool, error) {
+	description := fmt.Sprintf("PR[%d] %s/%s#%d", pr.ID, pr.BaseRepo.OwnerName, pr.BaseRepo.Name, pr.Index)
+	conflict, _, err := AttemptThreeWayMerge(ctx,
+		tmpBasePath, gitRepo, pr.MergeBase, "base", "tracking", description)
+	if err != nil {
+		return false, err
+	}
 
 	if !conflict {
 		treeHash, err := git.NewCommand(ctx, "write-tree").RunInDir(tmpBasePath)

services/repository/files/cherry_pick.go

@@ -0,0 +1,126 @@
+// 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 files
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	"code.gitea.io/gitea/models"
+	repo_model "code.gitea.io/gitea/models/repo"
+	user_model "code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/structs"
+	"code.gitea.io/gitea/services/pull"
+)
+
+// CherryPick cherrypicks or reverts a commit to the given repository
+func CherryPick(ctx context.Context, repo *repo_model.Repository, doer *user_model.User, revert bool, opts *ApplyDiffPatchOptions) (*structs.FileResponse, error) {
+	if err := opts.Validate(ctx, repo, doer); err != nil {
+		return nil, err
+	}
+	message := strings.TrimSpace(opts.Message)
+
+	author, committer := GetAuthorAndCommitterUsers(opts.Author, opts.Committer, doer)
+
+	t, err := NewTemporaryUploadRepository(ctx, repo)
+	if err != nil {
+		log.Error("%v", err)
+	}
+	defer t.Close()
+	if err := t.Clone(opts.OldBranch); err != nil {
+		return nil, err
+	}
+	if err := t.SetDefaultIndex(); err != nil {
+		return nil, err
+	}
+
+	// Get the commit of the original branch
+	commit, err := t.GetBranchCommit(opts.OldBranch)
+	if err != nil {
+		return nil, err // Couldn't get a commit for the branch
+	}
+
+	// Assigned LastCommitID in opts if it hasn't been set
+	if opts.LastCommitID == "" {
+		opts.LastCommitID = commit.ID.String()
+	} else {
+		lastCommitID, err := t.gitRepo.ConvertToSHA1(opts.LastCommitID)
+		if err != nil {
+			return nil, fmt.Errorf("CherryPick: Invalid last commit ID: %v", err)
+		}
+		opts.LastCommitID = lastCommitID.String()
+		if commit.ID.String() != opts.LastCommitID {
+			return nil, models.ErrCommitIDDoesNotMatch{
+				GivenCommitID:   opts.LastCommitID,
+				CurrentCommitID: opts.LastCommitID,
+			}
+		}
+	}
+
+	commit, err = t.GetCommit(strings.TrimSpace(opts.Content))
+	if err != nil {
+		return nil, err
+	}
+	parent, err := commit.ParentID(0)
+	if err != nil {
+		parent = git.MustIDFromString(git.EmptyTreeSHA)
+	}
+
+	base, right := parent.String(), commit.ID.String()
+
+	if revert {
+		right, base = base, right
+	}
+
+	description := fmt.Sprintf("CherryPick %s onto %s", right, opts.OldBranch)
+	conflict, _, err := pull.AttemptThreeWayMerge(ctx,
+		t.basePath, t.gitRepo, base, opts.LastCommitID, right, description)
+	if err != nil {
+		return nil, fmt.Errorf("failed to three-way merge %s onto %s: %v", right, opts.OldBranch, err)
+	}
+
+	if conflict {
+		return nil, fmt.Errorf("failed to merge due to conflicts")
+	}
+
+	treeHash, err := t.WriteTree()
+	if err != nil {
+		// likely non-sensical tree due to merge conflicts...
+		return nil, err
+	}
+
+	// Now commit the tree
+	var commitHash string
+	if opts.Dates != nil {
+		commitHash, err = t.CommitTreeWithDate(author, committer, treeHash, message, opts.Signoff, opts.Dates.Author, opts.Dates.Committer)
+	} else {
+		commitHash, err = t.CommitTree(author, committer, treeHash, message, opts.Signoff)
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	// Then push this tree to NewBranch
+	if err := t.Push(doer, commitHash, opts.NewBranch); err != nil {
+		return nil, err
+	}
+
+	commit, err = t.GetCommit(commitHash)
+	if err != nil {
+		return nil, err
+	}
+
+	fileCommitResponse, _ := GetFileCommitResponse(repo, commit) // ok if fails, then will be nil
+	verification := GetPayloadCommitVerification(commit)
+	fileResponse := &structs.FileResponse{
+		Commit:       fileCommitResponse,
+		Verification: verification,
+	}
+
+	return fileResponse, nil
+}

services/repository/files/patch.go

@@ -0,0 +1,193 @@
+// 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 files
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	"code.gitea.io/gitea/models"
+	repo_model "code.gitea.io/gitea/models/repo"
+	user_model "code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/structs"
+	asymkey_service "code.gitea.io/gitea/services/asymkey"
+)
+
+// ApplyDiffPatchOptions holds the repository diff patch update options
+type ApplyDiffPatchOptions struct {
+	LastCommitID string
+	OldBranch    string
+	NewBranch    string
+	Message      string
+	Content      string
+	SHA          string
+	Author       *IdentityOptions
+	Committer    *IdentityOptions
+	Dates        *CommitDateOptions
+	Signoff      bool
+}
+
+// Validate validates the provided options
+func (opts *ApplyDiffPatchOptions) Validate(ctx context.Context, repo *repo_model.Repository, doer *user_model.User) error {
+	// If no branch name is set, assume master
+	if opts.OldBranch == "" {
+		opts.OldBranch = repo.DefaultBranch
+	}
+	if opts.NewBranch == "" {
+		opts.NewBranch = opts.OldBranch
+	}
+
+	gitRepo, closer, err := git.RepositoryFromContextOrOpen(ctx, repo.RepoPath())
+	if err != nil {
+		return err
+	}
+	defer closer.Close()
+
+	// oldBranch must exist for this operation
+	if _, err := gitRepo.GetBranch(opts.OldBranch); err != nil {
+		return err
+	}
+	// A NewBranch can be specified for the patch to be applied to.
+	// Check to make sure the branch does not already exist, otherwise we can't proceed.
+	// If we aren't branching to a new branch, make sure user can commit to the given branch
+	if opts.NewBranch != opts.OldBranch {
+		existingBranch, err := gitRepo.GetBranch(opts.NewBranch)
+		if existingBranch != nil {
+			return models.ErrBranchAlreadyExists{
+				BranchName: opts.NewBranch,
+			}
+		}
+		if err != nil && !git.IsErrBranchNotExist(err) {
+			return err
+		}
+	} else {
+		protectedBranch, err := models.GetProtectedBranchBy(repo.ID, opts.OldBranch)
+		if err != nil {
+			return err
+		}
+		if protectedBranch != nil && !protectedBranch.CanUserPush(doer.ID) {
+			return models.ErrUserCannotCommit{
+				UserName: doer.LowerName,
+			}
+		}
+		if protectedBranch != nil && protectedBranch.RequireSignedCommits {
+			_, _, _, err := asymkey_service.SignCRUDAction(ctx, repo.RepoPath(), doer, repo.RepoPath(), opts.OldBranch)
+			if err != nil {
+				if !asymkey_service.IsErrWontSign(err) {
+					return err
+				}
+				return models.ErrUserCannotCommit{
+					UserName: doer.LowerName,
+				}
+			}
+		}
+	}
+	return nil
+}
+
+// ApplyDiffPatch applies a patch to the given repository
+func ApplyDiffPatch(ctx context.Context, repo *repo_model.Repository, doer *user_model.User, opts *ApplyDiffPatchOptions) (*structs.FileResponse, error) {
+	if err := opts.Validate(ctx, repo, doer); err != nil {
+		return nil, err
+	}
+
+	message := strings.TrimSpace(opts.Message)
+
+	author, committer := GetAuthorAndCommitterUsers(opts.Author, opts.Committer, doer)
+
+	t, err := NewTemporaryUploadRepository(ctx, repo)
+	if err != nil {
+		log.Error("%v", err)
+	}
+	defer t.Close()
+	if err := t.Clone(opts.OldBranch); err != nil {
+		return nil, err
+	}
+	if err := t.SetDefaultIndex(); err != nil {
+		return nil, err
+	}
+
+	// Get the commit of the original branch
+	commit, err := t.GetBranchCommit(opts.OldBranch)
+	if err != nil {
+		return nil, err // Couldn't get a commit for the branch
+	}
+
+	// Assigned LastCommitID in opts if it hasn't been set
+	if opts.LastCommitID == "" {
+		opts.LastCommitID = commit.ID.String()
+	} else {
+		lastCommitID, err := t.gitRepo.ConvertToSHA1(opts.LastCommitID)
+		if err != nil {
+			return nil, fmt.Errorf("ApplyPatch: Invalid last commit ID: %v", err)
+		}
+		opts.LastCommitID = lastCommitID.String()
+		if commit.ID.String() != opts.LastCommitID {
+			return nil, models.ErrCommitIDDoesNotMatch{
+				GivenCommitID:   opts.LastCommitID,
+				CurrentCommitID: opts.LastCommitID,
+			}
+		}
+	}
+
+	stdout := &strings.Builder{}
+	stderr := &strings.Builder{}
+
+	args := []string{"apply", "--index", "--recount", "--cached", "--ignore-whitespace", "--whitespace=fix", "--binary"}
+
+	if git.CheckGitVersionAtLeast("2.32") == nil {
+		args = append(args, "-3")
+	}
+
+	cmd := git.NewCommand(ctx, args...)
+	if err := cmd.RunWithContext(&git.RunContext{
+		Timeout: -1,
+		Dir:     t.basePath,
+		Stdout:  stdout,
+		Stderr:  stderr,
+		Stdin:   strings.NewReader(opts.Content),
+	}); err != nil {
+		return nil, fmt.Errorf("Error: Stdout: %s\nStderr: %s\nErr: %v", stdout.String(), stderr.String(), err)
+	}
+
+	// Now write the tree
+	treeHash, err := t.WriteTree()
+	if err != nil {
+		return nil, err
+	}
+
+	// Now commit the tree
+	var commitHash string
+	if opts.Dates != nil {
+		commitHash, err = t.CommitTreeWithDate(author, committer, treeHash, message, opts.Signoff, opts.Dates.Author, opts.Dates.Committer)
+	} else {
+		commitHash, err = t.CommitTree(author, committer, treeHash, message, opts.Signoff)
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	// Then push this tree to NewBranch
+	if err := t.Push(doer, commitHash, opts.NewBranch); err != nil {
+		return nil, err
+	}
+
+	commit, err = t.GetCommit(commitHash)
+	if err != nil {
+		return nil, err
+	}
+
+	fileCommitResponse, _ := GetFileCommitResponse(repo, commit) // ok if fails, then will be nil
+	verification := GetPayloadCommitVerification(commit)
+	fileResponse := &structs.FileResponse{
+		Commit:       fileCommitResponse,
+		Verification: verification,
+	}
+
+	return fileResponse, nil
+}

templates/repo/branch_dropdown.tmpl

@@ -1,37 +1,51 @@
 {{$release := .release}}
+{{$defaultBranch := $.root.BranchName}}{{if and .root.IsViewTag (not .noTag)}}{{$defaultBranch = .root.TagName}}{{end}}{{if eq $defaultBranch ""}}{{$defaultBranch = $.root.Repository.DefaultBranch}}{{end}}
 {{$showBranchesInDropdown := not .root.HideBranchesInDropdown}}
 <div class="fitted item choose reference{{if not $release}} mr-1{{end}}">
-	<div class="ui floating filter dropdown custom" data-can-create-branch="{{.root.CanCreateBranch}}" data-no-results="{{.root.i18n.Tr "repo.pulls.no_results"}}">
+	<div class="ui floating filter dropdown custom"
+		data-branch-form="{{if $.branchForm}}{{$.branchForm}}{{end}}"
+		data-can-create-branch="{{if .canCreateBranch}}{{.canCreateBranch}}{{else}}{{.root.CanCreateBranch}}{{end}}"
+		data-no-results="{{.root.i18n.Tr "repo.pulls.no_results"}}"
+		data-set-action="{{.setAction}}" data-submit-form="{{.submitForm}}"
+		data-view-type="{{if and .root.IsViewTag (not .noTag)}}tag{{else if .root.IsViewBranch}}branch{{else}}tree{{end}}"
+		data-ref-name="{{if and .root.IsViewTag (not .noTag)}}{{.root.TagName}}{{else if .root.IsViewBranch}}{{.root.BranchName}}{{else}}{{ShortSha .root.CommitID}}{{end}}"
+		data-branch-url-prefix="{{if .branchURLPrefix}}{{.branchURLPrefix}}{{else}}{{$.root.RepoLink}}/{{if $.root.PageIsCommits}}commits{{else}}src{{end}}/branch/{{end}}"
+		data-branch-url-suffix="{{if .branchURLSuffix}}{{.branchURLSuffix}}{{else}}{{if $.root.TreePath}}/{{PathEscapeSegments $.root.TreePath}}{{end}}{{end}}"
+		data-tag-url-prefix="{{if .tagURLPrefix}}{{.tagURLPrefix}}{{else if $release}}{{$.root.RepoLink}}/compare/{{else}}{{$.root.RepoLink}}/{{if $.root.PageIsCommits}}commits{{else}}src{{end}}/tag/{{end}}"
+		data-tag-url-suffix="{{if .tagURLSuffix}}{{.tagURLSuffix}}{{else if $release}}...{{if $release.IsDraft}}{{PathEscapeSegments $release.Target}}{{else}}{{if $release.TagName}}{{PathEscapeSegments $release.TagName}}{{else}}{{PathEscapeSegments $release.Sha1}}{{end}}{{end}}{{else}}{{if $.root.TreePath}}/{{PathEscapeSegments $.root.TreePath}}{{end}}{{end}}">
 		<div class="ui basic small compact button" @click="menuVisible = !menuVisible" @keyup.enter="menuVisible = !menuVisible">
 			<span class="text">
 				{{if $release}}
 					{{.root.i18n.Tr "repo.release.compare"}}
 				{{else}}
-					{{if .root.IsViewTag}}{{svg "octicon-tag"}}{{else}}{{svg "octicon-git-branch"}}{{end}}
+					<span :class="{visible: isViewTag}" v-if="isViewTag" v-cloak>{{svg "octicon-tag"}} {{.root.i18n.Tr "repo.tag"}}:</span>
-					{{if .root.IsViewBranch}}{{.root.i18n.Tr "repo.branch"}}{{else if .root.IsViewTag}}{{.root.i18n.Tr "repo.tag"}}{{else}}{{.root.i18n.Tr "repo.tree"}}{{end}}:
+					<span :class="{visible: isViewBranch}" v-if="isViewBranch" v-cloak>{{svg "octicon-git-branch"}} {{.root.i18n.Tr "repo.branch"}}:</span>
-					<strong>{{if .root.IsViewBranch}}{{.root.BranchName}}{{else if .root.IsViewTag}}{{.root.TagName}}{{else}}{{ShortSha .root.CommitID}}{{end}}</strong>
+					<span :class="{visible: isViewTree}" v-if="isViewTree" v-cloak>{{svg "octicon-git-branch"}} {{.root.i18n.Tr "repo.tree"}}:</span>
+					<strong ref="dropdownRefName">{{if and .root.IsViewTag (not .noTag)}}{{.root.TagName}}{{else if .root.IsViewBranch}}{{.root.BranchName}}{{else}}{{ShortSha .root.CommitID}}{{end}}</strong>
 				{{end}}
 			</span>
 			{{svg "octicon-triangle-down" 14 "dropdown icon"}}
 		</div>
-		<div class="data" style="display: none" data-mode="{{if .root.IsViewTag}}tags{{else}}branches{{end}}">
+		<div class="data" style="display: none" data-mode="{{if or .root.IsViewTag .isTag}}tags{{else}}branches{{end}}">
 			{{if $showBranchesInDropdown}}
 				{{range .root.Branches}}
-					<div class="item branch {{if eq $.root.BranchName .}}selected{{end}}" data-url="{{$.root.RepoLink}}/{{if $.root.PageIsCommits}}commits{{else}}src{{end}}/branch/{{PathEscapeSegments .}}{{if $.root.TreePath}}/{{PathEscapeSegments $.root.TreePath}}{{end}}">{{.}}</div>
+					<div class="item branch {{if eq $defaultBranch .}}selected{{end}}" data-url="{{PathEscapeSegments .}}">{{.}}</div>
 				{{end}}
 			{{end}}
+			{{if (not .noTag)}}
 				{{range .root.Tags}}
 					{{if $release}}
-					<div class="item tag {{if eq $release.TagName .}}selected{{end}}" data-url="{{$.root.RepoLink}}/compare/{{PathEscapeSegments .}}...{{if $release.IsDraft}}{{PathEscapeSegments $release.Target}}{{else}}{{if $release.TagName}}{{PathEscapeSegments $release.TagName}}{{else}}{{PathEscapeSegments $release.Sha1}}{{end}}{{end}}">{{.}}</div>
+						<div class="item tag {{if eq $release.TagName .}}selected{{end}}" data-url="{{PathEscapeSegments .}}">{{.}}</div>
 					{{else}}
-					<div class="item tag {{if eq $.root.BranchName .}}selected{{end}}" data-url="{{$.root.RepoLink}}/{{if $.root.PageIsCommits}}commits{{else}}src{{end}}/tag/{{PathEscapeSegments .}}{{if $.root.TreePath}}/{{PathEscapeSegments $.root.TreePath}}{{end}}">{{.}}</div>
+						<div class="item tag {{if eq $defaultBranch .}}selected{{end}}" data-url="{{PathEscapeSegments .}}">{{.}}</div>
+					{{end}}
 				{{end}}
 			{{end}}
 		</div>
 		<div class="menu transition" :class="{visible: menuVisible}" v-if="menuVisible" v-cloak>
 			<div class="ui icon search input">
 				<i class="icon df ac jc m-0">{{svg "octicon-filter" 16}}</i>
-				<input name="search" ref="searchField" autocomplete="off" v-model="searchTerm" @keydown="keydown($event)" placeholder="{{if $showBranchesInDropdown}}{{.root.i18n.Tr "repo.filter_branch_and_tag"}}{{else}}{{.root.i18n.Tr "repo.find_tag"}}{{end}}...">
+				<input name="search" ref="searchField" autocomplete="off" v-model="searchTerm" @keydown="keydown($event)" placeholder="{{if $.noTag}}{{.root.i18n.Tr "repo.filter_branch"}}{{else if $showBranchesInDropdown}}{{.root.i18n.Tr "repo.filter_branch_and_tag"}}{{else}}{{.root.i18n.Tr "repo.find_tag"}}{{end}}...">
 			</div>
 			{{if $showBranchesInDropdown}}
 				<div class="header branch-tag-choice">
@@ -42,11 +56,13 @@
 									{{svg "octicon-git-branch" 16 "mr-2"}}{{.root.i18n.Tr "repo.branches"}}
 								</span>
 							</a>
+							{{if not .noTag}}
 								<a class="reference column" href="#" @click="createTag = true; mode = 'tags'; focusSearchField()">
 									<span class="text" :class="{black: mode == 'tags'}">
 										{{svg "octicon-tag" 16 "mr-2"}}{{.root.i18n.Tr "repo.tags"}}
 									</span>
 								</a>
+							{{end}}
 						</div>
 					</div>
 				</div>

templates/repo/commit_page.tmpl

@@ -18,14 +18,123 @@
 			{{end}}
 		{{end}}
 		<div class="ui top attached header clearing segment pr {{$class}}">
+			<div class="df mb-4">
+				<h3 class="mb-0 f1"><span class="commit-summary" title="{{.Commit.Summary}}">{{RenderCommitMessage $.Context .Commit.Message $.RepoLink $.Repository.ComposeMetas}}</span>{{template "repo/commit_statuses" dict "Status" .CommitStatus "Statuses" .CommitStatuses  "root" $}}</h3>
 				{{if not $.PageIsWiki}}
-			<a class="ui blue tiny button browse-button" href="{{.SourcePath}}">
+					<div class="ui">
+						<a class="ui blue tiny button" href="{{.SourcePath}}">
 							{{.i18n.Tr "repo.diff.browse_source"}}
 						</a>
+						{{if and ($.Permission.CanWrite $.UnitTypeCode) (not $.Repository.IsArchived) (not .IsDeleted)}}{{- /* */ -}}
+							<div class="ui blue tiny floating dropdown icon button">{{.i18n.Tr "repo.commit.actions"}}
+								{{svg "octicon-triangle-down" 14 "dropdown icon"}}<span class="sr-mobile-only">{{.i18n.Tr "repo.commit.actions"}}</span>
+								<div class="menu">
+									<div class="ui header">{{.i18n.Tr "repo.commit.actions"}}</div>
+									<div class="divider"></div>
+									<div class="item show-create-branch-modal"
+										data-content="{{$.i18n.Tr "repo.branch.new_branch_from" (.CommitID)}}"
+										data-branch-from="{{ShortSha .CommitID}}"
+										data-branch-from-urlcomponent="{{.CommitID}}"
+										data-modal="#create-branch-modal">
+										{{.i18n.Tr "repo.branch.create_branch_operation"}}
+									</div>
+									<div class="item show-create-branch-modal"
+										data-content="{{$.i18n.Tr "repo.branch.new_branch_from" (.CommitID)}}"
+										data-branch-from="{{ShortSha .CommitID}}"
+										data-branch-from-urlcomponent="{{.CommitID}}"
+										data-modal="#create-tag-modal"
+										data-modal-from-span="#modal-create-tag-from-span"
+										data-modal-form="#create-tag-form">
+										{{.i18n.Tr "repo.tag.create_tag_operation"}}
+									</div>
+									<div class="item show-modal revert-button"
+										data-modal="#cherry-pick-modal"
+										data-modal-cherry-pick-type="revert"
+										data-modal-cherry-pick-header="{{$.i18n.Tr "repo.commit.revert-header" (ShortSha .CommitID)}}"
+										data-modal-cherry-pick-content="{{$.i18n.Tr "repo.commit.revert-content"}}"
+										data-modal-cherry-pick-submit="{{.i18n.Tr "repo.commit.revert"}}">{{.i18n.Tr "repo.commit.revert"}}</a></div>
+									<div class="item cherry-pick-button show-modal"
+										data-modal="#cherry-pick-modal"
+										data-modal-cherry-pick-type="cherry-pick"
+										data-modal-cherry-pick-header="{{$.i18n.Tr "repo.commit.cherry-pick-header" (ShortSha .CommitID)}}"
+										data-modal-cherry-pick-content="{{$.i18n.Tr "repo.commit.cherry-pick-content"}}"
+										data-modal-cherry-pick-submit="{{.i18n.Tr "repo.commit.cherry-pick"}}">{{.i18n.Tr "repo.commit.cherry-pick"}}</a></div>
+									<div class="ui basic modal" id="cherry-pick-modal">
+										<div class="ui icon header">
+											<span id="cherry-pick-header"></span>
+										</div>
+										<div class="content center">
+											<p id="cherry-pick-content" class="branch-dropdown"></p>
+											{{template "repo/branch_dropdown" dict "root" .
+												"noTag" "true" "canCreateBranch" "false"
+												"branchForm" "branch-dropdown-form"
+												"branchURLPrefix" (printf "%s/_cherrypick/%s/" $.RepoLink .CommitID) "branchURLSuffix" ""
+												"setAction" "true" "submitForm" "true"}}
+											<form method="GET" action="{{$.RepoLink}}/_cherrypick/{{.CommitID}}/{{if $.BranchName}}{{PathEscapeSegments $.BranchName}}{{else}}{{PathEscapeSegments $.Repository.DefaultBranch}}{{end}}" id="branch-dropdown-form">
+												<input type="hidden" name="ref" value="{{if $.BranchName}}{{$.BranchName}}{{else}}{{$.Repository.DefaultBranch}}{{end}}">
+												<input type="hidden" name="refType" value="branch">
+												<input type="hidden" id="cherry-pick-type" name="cherry-pick-type"><br/>
+												<button type="submit" id="cherry-pick-submit" class="ui green button"></button>
+											</form>
+										</div>
+									</div>
+									<div class="ui small modal" id="create-branch-modal">
+										<div class="header">
+											{{.i18n.Tr "repo.branch.new_branch"}}
+										</div>
+										<div class="content">
+											<form class="ui form" id="create-branch-form" action="" data-base-action="{{.RepoLink}}/branches/_new/commit/" method="post">
+												{{.CsrfTokenHtml}}
+												<div class="field">
+													<label>
+														{{.i18n.Tr "repo.branch.new_branch_from" "<span class=\"text\" id=\"modal-create-branch-from-span\"></span>" | Safe }}
+													</label>
+												</div>
+												<div class="required field">
+													<label for="new_branch_name">{{.i18n.Tr "repo.branch.name"}}</label>
+													<input id="new_branch_name" name="new_branch_name" required>
+												</div>
+
+												<div class="text right actions">
+													<div class="ui cancel button">{{.i18n.Tr "settings.cancel"}}</div>
+													<button class="ui green button">{{.i18n.Tr "repo.branch.confirm_create_branch"}}</button>
+												</div>
+											</form>
+										</div>
+									</div>
+									<div class="ui small modal" id="create-tag-modal">
+										<div class="header">
+											{{.i18n.Tr "repo.tag.create_tag_operation"}}
+										</div>
+										<div class="content">
+											<form class="ui form" id="create-tag-form" action="" data-base-action="{{.RepoLink}}/branches/_new/commit/" method="post">
+												{{.CsrfTokenHtml}}
+												<input type="hidden" name="create_tag" value="true">
+												<div class="field">
+													<label>
+														{{.i18n.Tr "repo.tag.create_tag_from" "<span class=\"text\" id=\"modal-create-tag-from-span\"></span>" | Safe }}
+													</label>
+												</div>
+												<div class="required field">
+													<label for="new_branch_name">{{.i18n.Tr "repo.release.tag_name"}}</label>
+													<input id="new_branch_name" name="new_branch_name" required>
+												</div>
+
+												<div class="text right actions">
+													<div class="ui cancel button">{{.i18n.Tr "settings.cancel"}}</div>
+													<button class="ui green button">{{.i18n.Tr "repo.tag.confirm_create_tag"}}</button>
+												</div>
+											</form>
+										</div>
+									</div>
+								</div>
+							</div>
 						{{end}}
-			<h3 class="mt-0"><span class="message-wrapper"><span class="commit-summary" title="{{.Commit.Summary}}">{{RenderCommitMessage $.Context .Commit.Message $.RepoLink $.Repository.ComposeMetas}}</span></span>{{template "repo/commit_statuses" dict "Status" .CommitStatus "Statuses" .CommitStatuses  "root" $}}</h3>
+					</div>
+				{{end}}
+			</div>
 			{{if IsMultilineCommitMessage .Commit.Message}}
-				<pre class="commit-body">{{RenderCommitBody $.Context .Commit.Message $.RepoLink $.Repository.ComposeMetas}}</pre>
+				<pre class="commit-body mt-0">{{RenderCommitBody $.Context .Commit.Message $.RepoLink $.Repository.ComposeMetas}}</pre>
 			{{end}}
 			{{if .BranchName}}
 				<span class="text grey mr-3">{{svg "octicon-git-branch" 16 "mr-2"}}{{.BranchName}}</span>

templates/repo/editor/cherry_pick.tmpl

@@ -0,0 +1,32 @@
+{{template "base/head" .}}
+<div class="page-content repository file editor edit">
+	{{template "repo/header" .}}
+	<div class="ui container">
+		{{template "base/alert" .}}
+		<form class="ui edit form" method="post" action="{{.RepoLink}}/_cherrypick/{{.SHA}}/{{.BranchName  | PathEscapeSegments}}">
+			{{.CsrfTokenHtml}}
+			<input type="hidden" name="last_commit" value="{{.last_commit}}">
+			<input type="hidden" name="page_has_posted" value="true">
+			<input type="hidden" name="revert" value="{{if eq .CherryPickType "revert"}}true{{else}}false{{end}}">
+			<div class="ui secondary menu">
+				<div class="fitted item treepath">
+					<div class="ui breadcrumb field {{if .Err_TreePath}}error{{end}}">
+						{{$shaurl := printf "%s/commit/%s" $.RepoLink (PathEscape .SHA)}}
+						{{$shalink := printf "<a class=\"ui blue sha label\" href=\"%s\">%s</a>" (Escape $shaurl) (ShortSha .SHA)}}
+						{{if eq .CherryPickType "revert"}}
+							{{.i18n.Tr "repo.editor.revert" $shalink | Str2html}}
+						{{else}}
+							{{.i18n.Tr "repo.editor.cherry_pick" $shalink | Str2html}}
+						{{end}}
+						<a class="section" href="{{$.RepoLink}}">{{.Repository.FullName}}</a>
+						<div class="divider">:</div>
+						<a class="section" href="{{$.BranchLink}}">{{.BranchName}}</a>
+						<span>{{.i18n.Tr "repo.editor.or"}} <a href="{{$shaurl}}">{{.i18n.Tr "repo.editor.cancel_lower"}}</a></span>
+					</div>
+				</div>
+			</div>
+			{{template "repo/editor/commit_form" .}}
+		</form>
+	</div>
+</div>
+{{template "base/footer" .}}

templates/repo/editor/patch.tmpl

@@ -0,0 +1,59 @@
+{{template "base/head" .}}
+<div class="page-content repository file editor edit">
+	{{template "repo/header" .}}
+	<div class="ui container">
+		{{template "base/alert" .}}
+		<form class="ui edit form" method="post" action="{{.RepoLink}}/_diffpatch/{{.BranchName  | PathEscapeSegments}}">
+			{{.CsrfTokenHtml}}
+			<input type="hidden" name="last_commit" value="{{.last_commit}}">
+			<input type="hidden" name="page_has_posted" value="{{.PageHasPosted}}">
+			<div class="ui secondary menu">
+				<div class="fitted item treepath">
+					<div class="ui breadcrumb field {{if .Err_TreePath}}error{{end}}">
+						{{.i18n.Tr "repo.editor.patching"}}
+						<a class="section" href="{{$.RepoLink}}">{{.Repository.FullName}}</a>
+						<div class="divider">:</div>
+						<a class="section" href="{{$.BranchLink}}">{{.BranchName}}</a>
+						<span>{{.i18n.Tr "repo.editor.or"}} <a href="{{$.BranchLink}}">{{.i18n.Tr "repo.editor.cancel_lower"}}</a></span>
+						<input type="hidden" id="tree_path" name="tree_path" value="patch" required>
+						<input id="file-name" type="hidden" value="diff.patch">
+					</div>
+				</div>
+			</div>
+			<div class="field">
+				<div class="ui top attached tabular menu" data-write="write">
+					<a class="active item" data-tab="write">{{svg "octicon-code" 16 "mr-2"}}{{.i18n.Tr "repo.editor.new_patch"}}</a>
+				</div>
+				<div class="ui bottom attached active tab segment" data-tab="write">
+					<textarea id="edit_area" name="content" class="hide" data-id="repo-{{.Repository.Name}}-patch"
+						data-context="{{.RepoLink}}"
+						data-line-wrap-extensions="{{.LineWrapExtensions}}">
+{{.FileContent}}</textarea>
+					<div class="editor-loading is-loading"></div>
+				</div>
+			</div>
+			{{template "repo/editor/commit_form" .}}
+		</form>
+	</div>
+
+	<div class="ui small basic modal" id="edit-empty-content-modal">
+		<div class="ui icon header">
+			<i class="file icon"></i>
+			{{.i18n.Tr "repo.editor.commit_empty_file_header"}}
+		</div>
+		<div class="center content">
+			<p>{{.i18n.Tr "repo.editor.commit_empty_file_text"}}</p>
+		</div>
+		<div class="actions">
+			<div class="ui red basic cancel inverted button">
+				<i class="remove icon"></i>
+				{{.i18n.Tr "repo.editor.cancel"}}
+			</div>
+			<div class="ui green basic ok inverted button">
+				<i class="save icon"></i>
+				{{.i18n.Tr "repo.editor.commit_changes"}}
+			</div>
+		</div>
+	</div>
+</div>
+{{template "base/footer" .}}

templates/repo/home.tmpl

@@ -89,6 +89,11 @@
 								{{.i18n.Tr "repo.editor.upload_file"}}
 							</a>
 						{{end}}
+						{{if .CanAddFile}}
+							<a href="{{.RepoLink}}/_diffpatch/{{.BranchName | PathEscapeSegments}}/{{.TreePath | PathEscapeSegments}}" class="ui button">
+								{{.i18n.Tr "repo.editor.patch"}}
+							</a>
+						{{end}}
 					{{end}}
 					{{if and (ne $n 0) (not .IsViewFile) (not .IsBlame) }}
 						<a href="{{.RepoLink}}/commits/{{.BranchNameSubURL}}/{{.TreePath | PathEscapeSegments}}" class="ui button">

templates/swagger/v1_json.tmpl

@@ -3383,6 +3383,50 @@
         }
       }
     },
+    "/repos/{owner}/{repo}/diffpatch": {
+      "post": {
+        "consumes": [
+          "application/json"
+        ],
+        "produces": [
+          "application/json"
+        ],
+        "tags": [
+          "repository"
+        ],
+        "summary": "Apply diff patch to repository",
+        "operationId": "repoApplyDiffPatch",
+        "parameters": [
+          {
+            "type": "string",
+            "description": "owner of the repo",
+            "name": "owner",
+            "in": "path",
+            "required": true
+          },
+          {
+            "type": "string",
+            "description": "name of the repo",
+            "name": "repo",
+            "in": "path",
+            "required": true
+          },
+          {
+            "name": "body",
+            "in": "body",
+            "required": true,
+            "schema": {
+              "$ref": "#/definitions/UpdateFileOptions"
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "$ref": "#/responses/FileResponse"
+          }
+        }
+      }
+    },
     "/repos/{owner}/{repo}/editorconfig/{filepath}": {
       "get": {
         "produces": [

web_src/js/components/RepoBranchTagDropdown.js

@@ -10,11 +10,22 @@ export function initRepoBranchTagDropdown(selector) {
       items: [],
       mode: $data.data('mode'),
       searchTerm: '',
+      refName: '',
       noResults: '',
       canCreateBranch: false,
       menuVisible: false,
       createTag: false,
-      active: 0
+      isViewTag: false,
+      isViewBranch: false,
+      isViewTree: false,
+      active: 0,
+      branchForm: '',
+      branchURLPrefix: '',
+      branchURLSuffix: '',
+      tagURLPrefix: '',
+      tagURLSuffix: '',
+      setAction: false,
+      submitForm: false,
     };
     $data.find('.item').each(function () {
       data.items.push({
@@ -64,6 +75,26 @@ export function initRepoBranchTagDropdown(selector) {
       beforeMount() {
         this.noResults = this.$el.getAttribute('data-no-results');
         this.canCreateBranch = this.$el.getAttribute('data-can-create-branch') === 'true';
+        this.branchForm = this.$el.getAttribute('data-branch-form');
+        switch (this.$el.getAttribute('data-view-type')) {
+          case 'tree':
+            this.isViewTree = true;
+            break;
+          case 'tag':
+            this.isViewTag = true;
+            break;
+          default:
+            this.isViewBranch = true;
+            break;
+        }
+        this.refName = this.$el.getAttribute('data-ref-name');
+        this.branchURLPrefix = this.$el.getAttribute('data-branch-url-prefix');
+        this.branchURLSuffix = this.$el.getAttribute('data-branch-url-suffix');
+        this.tagURLPrefix = this.$el.getAttribute('data-tag-url-prefix');
+        this.tagURLSuffix = this.$el.getAttribute('data-tag-url-suffix');
+        this.setAction = this.$el.getAttribute('data-set-action') === 'true';
+        this.submitForm = this.$el.getAttribute('data-submit-form') === 'true';
+
 
         document.body.addEventListener('click', (event) => {
           if (this.$el.contains(event.target)) return;
@@ -80,7 +111,32 @@ export function initRepoBranchTagDropdown(selector) {
             prev.selected = false;
           }
           item.selected = true;
-          window.location.href = item.url;
+          const url = (item.tag) ? this.tagURLPrefix + item.url + this.tagURLSuffix : this.branchURLPrefix + item.url + this.branchURLSuffix;
+          if (this.branchForm === '') {
+            window.location.href = url;
+          } else {
+            this.isViewTree = false;
+            this.isViewTag = false;
+            this.isViewBranch = false;
+            this.$refs.dropdownRefName.textContent = item.name;
+            if (this.setAction) {
+              $(`#${this.branchForm}`).attr('action', url);
+            } else {
+              $(`#${this.branchForm} input[name="refURL"]`).val(url);
+            }
+            $(`#${this.branchForm} input[name="ref"]`).val(item.name);
+            if (item.tag) {
+              this.isViewTag = true;
+              $(`#${this.branchForm} input[name="refType"]`).val('tag');
+            } else {
+              this.isViewBranch = true;
+              $(`#${this.branchForm} input[name="refType"]`).val('branch');
+            }
+            if (this.submitForm) {
+              $(`#${this.branchForm}`).trigger('submit');
+            }
+            Vue.set(this, 'menuVisible', false);
+          }
         },
         createNewBranch() {
           if (!this.showCreateNewBranch) return;

web_src/js/features/common-global.js

@@ -313,9 +313,22 @@ export function initGlobalButtons() {
     alert('Nothing to hide');
   });
 
-  $('.show-modal.button').on('click', function () {
+  $('.show-modal').on('click', function () {
-    $($(this).data('modal')).modal('show');
+    const modalDiv = $($(this).attr('data-modal'));
-    const colorPickers = $($(this).data('modal')).find('.color-picker');
+    for (const attrib of this.attributes) {
+      if (!attrib.name.startsWith('data-modal-')) {
+        continue;
+      }
+      const id = attrib.name.substring(11);
+      const target = modalDiv.find(`#${id}`);
+      if (target.is('input')) {
+        target.val(attrib.value);
+      } else {
+        target.text(attrib.value);
+      }
+    }
+    modalDiv.modal('show');
+    const colorPickers = $($(this).attr('data-modal')).find('.color-picker');
     if (colorPickers.length > 0) {
       initCompColorPicker();
     }
@@ -323,10 +336,10 @@ export function initGlobalButtons() {
 
   $('.delete-post.button').on('click', function () {
     const $this = $(this);
-    $.post($this.data('request-url'), {
+    $.post($this.attr('data-request-url'), {
       _csrf: csrfToken
     }).done(() => {
-      window.location.href = $this.data('done-url');
+      window.location.href = $this.attr('data-done-url');
     });
   });
 }

web_src/js/features/repo-branch.js

@@ -1,9 +1,18 @@
 import $ from 'jquery';
 
 export function initRepoBranchButton() {
-  $('.show-create-branch-modal.button').on('click', function () {
+  $('.show-create-branch-modal').on('click', function () {
-    $('#create-branch-form')[0].action = $('#create-branch-form').data('base-action') + $(this).data('branch-from-urlcomponent');
+    let modalFormName = $(this).attr('data-modal-form');
-    $('#modal-create-branch-from-span').text($(this).data('branch-from'));
+    if (!modalFormName) {
-    $($(this).data('modal')).modal('show');
+      modalFormName = '#create-branch-form';
+    }
+    $(modalFormName)[0].action = $(modalFormName).attr('data-base-action') + $(this).attr('data-branch-from-urlcomponent');
+    let fromSpanName = $(this).attr('data-modal-from-span');
+    if (!fromSpanName) {
+      fromSpanName = '#modal-create-branch-from-span';
+    }
+
+    $(fromSpanName).text($(this).attr('data-branch-from'));
+    $($(this).attr('data-modal')).modal('show');
   });
 }

web_src/js/features/repo-legacy.js

@@ -436,7 +436,7 @@ export function initRepository() {
   });
 
   // File list and commits
-  if ($('.repository.file.list').length > 0 ||
+  if ($('.repository.file.list').length > 0 || $('.branch-dropdown').length > 0 ||
     $('.repository.commits').length > 0 || $('.repository.release').length > 0) {
     initRepoBranchTagDropdown('.choose.reference .dropdown');
   }

web_src/less/_repository.less

@@ -2551,12 +2551,6 @@
   padding-top: 15px;
 }
 
-.browse-button {
-  position: absolute;
-  right: 1rem;
-  top: .75rem;
-}
-
 .commit-header-row {
   min-height: 50px !important;
   padding-top: 0 !important;