Edit file workflow for creating a fork and proposing changes (#34240)

When viewing a file that the user can't edit because they can't write to
the branch, the new, upload, patch, edit and delete functionality is no
longer disabled.

If no user fork of the repository exists, there is now a page to create one.
It will automatically create a fork with a single branch matching the one
being viewed, and a unique repository name will be automatically picked.

When a fork exists, but it's archived, a mirror or the user can't write
code to it, there will instead be a message explaining the situation.

If the usable fork exists, a message will appear at the top of the edit page
explaining that the changes will be applied to a branch in the fork. The
base repository branch will be pushed to a new branch to the fork, and
then the edits will be applied on top.

The suggestion to fork happens when accessing /_edit/, so that for
example online documentation can have an "edit this page" link to
the base repository that does the right thing.

Also includes changes to properly report errors when trying to commit
to a new branch that is protected, and when trying to commit to an
existing branch when choosing the new branch option.

Resolves #9017, #20882

---------

Co-authored-by: Brecht Van Lommel <[email protected]>
Co-authored-by: wxiaoguang <[email protected]>

Author: brechtvl

models/repo/repo.go

@@ -653,7 +653,7 @@ func (repo *Repository) AllowsPulls(ctx context.Context) bool {
 
 // CanEnableEditor returns true if repository meets the requirements of web editor.
 func (repo *Repository) CanEnableEditor() bool {
-	return !repo.IsMirror
+	return !repo.IsMirror && !repo.IsArchived
 }
 
 // DescriptionHTML does special handles to description and return HTML string.

options/locale/locale_en-US.ini

@@ -1399,6 +1399,13 @@ editor.revert = Revert %s onto:
 editor.failed_to_commit = Failed to commit changes.
 editor.failed_to_commit_summary = Error Message:
 
+editor.fork_create = Fork Repository to Propose Changes
+editor.fork_create_description = You can not edit this repository directly. Instead you can create a fork, make edits and create a pull request.
+editor.fork_edit_description = You can not edit this repository directly. The changes will be written to your fork <b>%s</b>, so you can create a pull request.
+editor.fork_not_editable = You have forked this repository but your fork is not editable.
+editor.fork_failed_to_push_branch = Failed to push branch %s to your repository.
+editor.fork_branch_exists = Branch "%s" already exists in your fork, please choose a new branch name.
+
 commits.desc = Browse source code change history.
 commits.commits = Commits
 commits.no_commits = No commits in common. "%s" and "%s" have entirely different histories.

routers/web/repo/editor.go

@@ -16,6 +16,7 @@ import (
 	"code.gitea.io/gitea/modules/charset"
 	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/httplib"
+	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/markup"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/templates"
@@ -39,26 +40,36 @@ const (
 	editorCommitChoiceNewBranch string = "commit-to-new-branch"
 )
 
-func prepareEditorCommitFormOptions(ctx *context.Context, editorAction string) {
+func prepareEditorCommitFormOptions(ctx *context.Context, editorAction string) *context.CommitFormOptions {
 	cleanedTreePath := files_service.CleanGitTreePath(ctx.Repo.TreePath)
 	if cleanedTreePath != ctx.Repo.TreePath {
 		redirectTo := fmt.Sprintf("%s/%s/%s/%s", ctx.Repo.RepoLink, editorAction, util.PathEscapeSegments(ctx.Repo.BranchName), util.PathEscapeSegments(cleanedTreePath))
 		if ctx.Req.URL.RawQuery != "" {
 			redirectTo += "?" + ctx.Req.URL.RawQuery
 		}
 		ctx.Redirect(redirectTo)
-		return
+		return nil
 	}
 
-	commitFormBehaviors, err := ctx.Repo.PrepareCommitFormBehaviors(ctx, ctx.Doer)
+	commitFormOptions, err := context.PrepareCommitFormOptions(ctx, ctx.Doer, ctx.Repo.Repository, ctx.Repo.Permission, ctx.Repo.RefFullName)
 	if err != nil {
-		ctx.ServerError("PrepareCommitFormBehaviors", err)
-		return
+		ctx.ServerError("PrepareCommitFormOptions", err)
+		return nil
+	}
+
+	if commitFormOptions.NeedFork {
+		ForkToEdit(ctx)
+		return nil
+	}
+
+	if commitFormOptions.WillSubmitToFork && !commitFormOptions.TargetRepo.CanEnableEditor() {
+		ctx.Data["NotFoundPrompt"] = ctx.Locale.Tr("repo.editor.fork_not_editable")
+		ctx.NotFound(nil)
 	}
 
 	ctx.Data["BranchLink"] = ctx.Repo.RepoLink + "/src/" + ctx.Repo.RefTypeNameSubURL()
 	ctx.Data["TreePath"] = ctx.Repo.TreePath
-	ctx.Data["CommitFormBehaviors"] = commitFormBehaviors
+	ctx.Data["CommitFormOptions"] = commitFormOptions
 
 	// for online editor
 	ctx.Data["PreviewableExtensions"] = strings.Join(markup.PreviewableExtensions(), ",")
@@ -69,33 +80,35 @@ func prepareEditorCommitFormOptions(ctx *context.Context, editorAction string) {
 	// form fields
 	ctx.Data["commit_summary"] = ""
 	ctx.Data["commit_message"] = ""
-	ctx.Data["commit_choice"] = util.Iif(commitFormBehaviors.CanCommitToBranch, editorCommitChoiceDirect, editorCommitChoiceNewBranch)
-	ctx.Data["new_branch_name"] = getUniquePatchBranchName(ctx, ctx.Doer.LowerName, ctx.Repo.Repository)
+	ctx.Data["commit_choice"] = util.Iif(commitFormOptions.CanCommitToBranch, editorCommitChoiceDirect, editorCommitChoiceNewBranch)
+	ctx.Data["new_branch_name"] = getUniquePatchBranchName(ctx, ctx.Doer.LowerName, commitFormOptions.TargetRepo)
 	ctx.Data["last_commit"] = ctx.Repo.CommitID
+	return commitFormOptions
 }
 
 func prepareTreePathFieldsAndPaths(ctx *context.Context, treePath string) {
 	// show the tree path fields in the "breadcrumb" and help users to edit the target tree path
-	ctx.Data["TreeNames"], ctx.Data["TreePaths"] = getParentTreeFields(treePath)
+	ctx.Data["TreeNames"], ctx.Data["TreePaths"] = getParentTreeFields(strings.TrimPrefix(treePath, "/"))
 }
 
-type parsedEditorCommitForm[T any] struct {
-	form                T
-	commonForm          *forms.CommitCommonForm
-	CommitFormBehaviors *context.CommitFormBehaviors
-	TargetBranchName    string
-	GitCommitter        *files_service.IdentityOptions
+type preparedEditorCommitForm[T any] struct {
+	form              T
+	commonForm        *forms.CommitCommonForm
+	CommitFormOptions *context.CommitFormOptions
+	OldBranchName     string
+	NewBranchName     string
+	GitCommitter      *files_service.IdentityOptions
 }
 
-func (f *parsedEditorCommitForm[T]) GetCommitMessage(defaultCommitMessage string) string {
+func (f *preparedEditorCommitForm[T]) GetCommitMessage(defaultCommitMessage string) string {
 	commitMessage := util.IfZero(strings.TrimSpace(f.commonForm.CommitSummary), defaultCommitMessage)
 	if body := strings.TrimSpace(f.commonForm.CommitMessage); body != "" {
 		commitMessage += "\n\n" + body
 	}
 	return commitMessage
 }
 
-func parseEditorCommitSubmittedForm[T forms.CommitCommonFormInterface](ctx *context.Context) *parsedEditorCommitForm[T] {
+func prepareEditorCommitSubmittedForm[T forms.CommitCommonFormInterface](ctx *context.Context) *preparedEditorCommitForm[T] {
 	form := web.GetForm(ctx).(T)
 	if ctx.HasError() {
 		ctx.JSONError(ctx.GetErrMsg())
@@ -105,15 +118,22 @@ func parseEditorCommitSubmittedForm[T forms.CommitCommonFormInterface](ctx *cont
 	commonForm := form.GetCommitCommonForm()
 	commonForm.TreePath = files_service.CleanGitTreePath(commonForm.TreePath)
 
-	commitFormBehaviors, err := ctx.Repo.PrepareCommitFormBehaviors(ctx, ctx.Doer)
+	commitFormOptions, err := context.PrepareCommitFormOptions(ctx, ctx.Doer, ctx.Repo.Repository, ctx.Repo.Permission, ctx.Repo.RefFullName)
 	if err != nil {
-		ctx.ServerError("PrepareCommitFormBehaviors", err)
+		ctx.ServerError("PrepareCommitFormOptions", err)
+		return nil
+	}
+	if commitFormOptions.NeedFork {
+		// It shouldn't happen, because we should have done the checks in the "GET" request. But just in case.
+		ctx.JSONError(ctx.Locale.TrString("error.not_found"))
 		return nil
 	}
 
 	// check commit behavior
-	targetBranchName := util.Iif(commonForm.CommitChoice == editorCommitChoiceNewBranch, commonForm.NewBranchName, ctx.Repo.BranchName)
-	if targetBranchName == ctx.Repo.BranchName && !commitFormBehaviors.CanCommitToBranch {
+	fromBaseBranch := ctx.FormString("from_base_branch")
+	commitToNewBranch := commonForm.CommitChoice == editorCommitChoiceNewBranch || fromBaseBranch != ""
+	targetBranchName := util.Iif(commitToNewBranch, commonForm.NewBranchName, ctx.Repo.BranchName)
+	if targetBranchName == ctx.Repo.BranchName && !commitFormOptions.CanCommitToBranch {
 		ctx.JSONError(ctx.Tr("repo.editor.cannot_commit_to_protected_branch", targetBranchName))
 		return nil
 	}
@@ -125,40 +145,73 @@ func parseEditorCommitSubmittedForm[T forms.CommitCommonFormInterface](ctx *cont
 		return nil
 	}
 
-	return &parsedEditorCommitForm[T]{
-		form:                form,
-		commonForm:          commonForm,
-		CommitFormBehaviors: commitFormBehaviors,
-		TargetBranchName:    targetBranchName,
-		GitCommitter:        gitCommitter,
+	if commitToNewBranch {
+		// if target branch exists, we should stop
+		targetBranchExists, err := git_model.IsBranchExist(ctx, commitFormOptions.TargetRepo.ID, targetBranchName)
+		if err != nil {
+			ctx.ServerError("IsBranchExist", err)
+			return nil
+		} else if targetBranchExists {
+			if fromBaseBranch != "" {
+				ctx.JSONError(ctx.Tr("repo.editor.fork_branch_exists", targetBranchName))
+			} else {
+				ctx.JSONError(ctx.Tr("repo.editor.branch_already_exists", targetBranchName))
+			}
+			return nil
+		}
+	}
+
+	oldBranchName := ctx.Repo.BranchName
+	if fromBaseBranch != "" {
+		err = editorPushBranchToForkedRepository(ctx, ctx.Doer, ctx.Repo.Repository.BaseRepo, fromBaseBranch, commitFormOptions.TargetRepo, targetBranchName)
+		if err != nil {
+			log.Error("Unable to editorPushBranchToForkedRepository: %v", err)
+			ctx.JSONError(ctx.Tr("repo.editor.fork_failed_to_push_branch", targetBranchName))
+			return nil
+		}
+		// we have pushed the base branch as the new branch, now we need to commit the changes directly to the new branch
+		oldBranchName = targetBranchName
+	}
+
+	return &preparedEditorCommitForm[T]{
+		form:              form,
+		commonForm:        commonForm,
+		CommitFormOptions: commitFormOptions,
+		OldBranchName:     oldBranchName,
+		NewBranchName:     targetBranchName,
+		GitCommitter:      gitCommitter,
 	}
 }
 
 // redirectForCommitChoice redirects after committing the edit to a branch
-func redirectForCommitChoice[T any](ctx *context.Context, parsed *parsedEditorCommitForm[T], treePath string) {
+func redirectForCommitChoice[T any](ctx *context.Context, parsed *preparedEditorCommitForm[T], treePath string) {
+	// when editing a file in a PR, it should return to the origin location
+	if returnURI := ctx.FormString("return_uri"); returnURI != "" && httplib.IsCurrentGiteaSiteURL(ctx, returnURI) {
+		ctx.JSONRedirect(returnURI)
+		return
+	}
+
 	if parsed.commonForm.CommitChoice == editorCommitChoiceNewBranch {
 		// Redirect to a pull request when possible
 		redirectToPullRequest := false
-		repo, baseBranch, headBranch := ctx.Repo.Repository, ctx.Repo.BranchName, parsed.TargetBranchName
-		if repo.UnitEnabled(ctx, unit.TypePullRequests) {
-			redirectToPullRequest = true
-		} else if parsed.CommitFormBehaviors.CanCreateBasePullRequest {
+		repo, baseBranch, headBranch := ctx.Repo.Repository, parsed.OldBranchName, parsed.NewBranchName
+		if ctx.Repo.Repository.IsFork && parsed.CommitFormOptions.CanCreateBasePullRequest {
 			redirectToPullRequest = true
 			baseBranch = repo.BaseRepo.DefaultBranch
 			headBranch = repo.Owner.Name + "/" + repo.Name + ":" + headBranch
 			repo = repo.BaseRepo
+		} else if repo.UnitEnabled(ctx, unit.TypePullRequests) {
+			redirectToPullRequest = true
 		}
 		if redirectToPullRequest {
 			ctx.JSONRedirect(repo.Link() + "/compare/" + util.PathEscapeSegments(baseBranch) + "..." + util.PathEscapeSegments(headBranch))
 			return
 		}
 	}
 
-	returnURI := ctx.FormString("return_uri")
-	if returnURI == "" || !httplib.IsCurrentGiteaSiteURL(ctx, returnURI) {
-		returnURI = util.URLJoin(ctx.Repo.RepoLink, "src/branch", util.PathEscapeSegments(parsed.TargetBranchName), util.PathEscapeSegments(treePath))
-	}
-	ctx.JSONRedirect(returnURI)
+	// redirect to the newly updated file
+	redirectTo := util.URLJoin(ctx.Repo.RepoLink, "src/branch", util.PathEscapeSegments(parsed.NewBranchName), util.PathEscapeSegments(treePath))
+	ctx.JSONRedirect(redirectTo)
 }
 
 func editFileOpenExisting(ctx *context.Context) (prefetch []byte, dataRc io.ReadCloser, fInfo *fileInfo) {
@@ -268,7 +321,7 @@ func EditFile(ctx *context.Context) {
 func EditFilePost(ctx *context.Context) {
 	editorAction := ctx.PathParam("editor_action")
 	isNewFile := editorAction == "_new"
-	parsed := parseEditorCommitSubmittedForm[*forms.EditRepoFileForm](ctx)
+	parsed := prepareEditorCommitSubmittedForm[*forms.EditRepoFileForm](ctx)
 	if ctx.Written() {
 		return
 	}
@@ -292,8 +345,8 @@ func EditFilePost(ctx *context.Context) {
 
 	_, err := files_service.ChangeRepoFiles(ctx, ctx.Repo.Repository, ctx.Doer, &files_service.ChangeRepoFilesOptions{
 		LastCommitID: parsed.form.LastCommit,
-		OldBranch:    ctx.Repo.BranchName,
-		NewBranch:    parsed.TargetBranchName,
+		OldBranch:    parsed.OldBranchName,
+		NewBranch:    parsed.NewBranchName,
 		Message:      parsed.GetCommitMessage(defaultCommitMessage),
 		Files: []*files_service.ChangeRepoFile{
 			{
@@ -308,7 +361,7 @@ func EditFilePost(ctx *context.Context) {
 		Committer: parsed.GitCommitter,
 	})
 	if err != nil {
-		editorHandleFileOperationError(ctx, parsed.TargetBranchName, err)
+		editorHandleFileOperationError(ctx, parsed.NewBranchName, err)
 		return
 	}
 
@@ -327,16 +380,16 @@ func DeleteFile(ctx *context.Context) {
 
 // DeleteFilePost response for deleting file
 func DeleteFilePost(ctx *context.Context) {
-	parsed := parseEditorCommitSubmittedForm[*forms.DeleteRepoFileForm](ctx)
+	parsed := prepareEditorCommitSubmittedForm[*forms.DeleteRepoFileForm](ctx)
 	if ctx.Written() {
 		return
 	}
 
 	treePath := ctx.Repo.TreePath
 	_, err := files_service.ChangeRepoFiles(ctx, ctx.Repo.Repository, ctx.Doer, &files_service.ChangeRepoFilesOptions{
 		LastCommitID: parsed.form.LastCommit,
-		OldBranch:    ctx.Repo.BranchName,
-		NewBranch:    parsed.TargetBranchName,
+		OldBranch:    parsed.OldBranchName,
+		NewBranch:    parsed.NewBranchName,
 		Files: []*files_service.ChangeRepoFile{
 			{
 				Operation: "delete",
@@ -349,38 +402,38 @@ func DeleteFilePost(ctx *context.Context) {
 		Committer: parsed.GitCommitter,
 	})
 	if err != nil {
-		editorHandleFileOperationError(ctx, parsed.TargetBranchName, err)
+		editorHandleFileOperationError(ctx, parsed.NewBranchName, err)
 		return
 	}
 
 	ctx.Flash.Success(ctx.Tr("repo.editor.file_delete_success", treePath))
-	redirectTreePath := getClosestParentWithFiles(ctx.Repo.GitRepo, parsed.TargetBranchName, treePath)
+	redirectTreePath := getClosestParentWithFiles(ctx.Repo.GitRepo, parsed.NewBranchName, treePath)
 	redirectForCommitChoice(ctx, parsed, redirectTreePath)
 }
 
 func UploadFile(ctx *context.Context) {
 	ctx.Data["PageIsUpload"] = true
-	upload.AddUploadContext(ctx, "repo")
 	prepareTreePathFieldsAndPaths(ctx, ctx.Repo.TreePath)
-
-	prepareEditorCommitFormOptions(ctx, "_upload")
+	opts := prepareEditorCommitFormOptions(ctx, "_upload")
 	if ctx.Written() {
 		return
 	}
+	upload.AddUploadContextForRepo(ctx, opts.TargetRepo)
+
 	ctx.HTML(http.StatusOK, tplUploadFile)
 }
 
 func UploadFilePost(ctx *context.Context) {
-	parsed := parseEditorCommitSubmittedForm[*forms.UploadRepoFileForm](ctx)
+	parsed := prepareEditorCommitSubmittedForm[*forms.UploadRepoFileForm](ctx)
 	if ctx.Written() {
 		return
 	}
 
 	defaultCommitMessage := ctx.Locale.TrString("repo.editor.upload_files_to_dir", util.IfZero(parsed.form.TreePath, "/"))
 	err := files_service.UploadRepoFiles(ctx, ctx.Repo.Repository, ctx.Doer, &files_service.UploadRepoFileOptions{
 		LastCommitID: parsed.form.LastCommit,
-		OldBranch:    ctx.Repo.BranchName,
-		NewBranch:    parsed.TargetBranchName,
+		OldBranch:    parsed.OldBranchName,
+		NewBranch:    parsed.NewBranchName,
 		TreePath:     parsed.form.TreePath,
 		Message:      parsed.GetCommitMessage(defaultCommitMessage),
 		Files:        parsed.form.Files,
@@ -389,7 +442,7 @@ func UploadFilePost(ctx *context.Context) {
 		Committer:    parsed.GitCommitter,
 	})
 	if err != nil {
-		editorHandleFileOperationError(ctx, parsed.TargetBranchName, err)
+		editorHandleFileOperationError(ctx, parsed.NewBranchName, err)
 		return
 	}
 	redirectForCommitChoice(ctx, parsed, parsed.form.TreePath)

routers/web/repo/editor_apply_patch.go

@@ -25,16 +25,16 @@ func NewDiffPatch(ctx *context.Context) {
 
 // NewDiffPatchPost response for sending patch page
 func NewDiffPatchPost(ctx *context.Context) {
-	parsed := parseEditorCommitSubmittedForm[*forms.EditRepoFileForm](ctx)
+	parsed := prepareEditorCommitSubmittedForm[*forms.EditRepoFileForm](ctx)
 	if ctx.Written() {
 		return
 	}
 
 	defaultCommitMessage := ctx.Locale.TrString("repo.editor.patch")
 	_, err := files.ApplyDiffPatch(ctx, ctx.Repo.Repository, ctx.Doer, &files.ApplyDiffPatchOptions{
 		LastCommitID: parsed.form.LastCommit,
-		OldBranch:    ctx.Repo.BranchName,
-		NewBranch:    parsed.TargetBranchName,
+		OldBranch:    parsed.OldBranchName,
+		NewBranch:    parsed.NewBranchName,
 		Message:      parsed.GetCommitMessage(defaultCommitMessage),
 		Content:      strings.ReplaceAll(parsed.form.Content.Value(), "\r\n", "\n"),
 		Author:       parsed.GitCommitter,
@@ -44,7 +44,7 @@ func NewDiffPatchPost(ctx *context.Context) {
 		err = util.ErrorWrapLocale(err, "repo.editor.fail_to_apply_patch")
 	}
 	if err != nil {
-		editorHandleFileOperationError(ctx, parsed.TargetBranchName, err)
+		editorHandleFileOperationError(ctx, parsed.NewBranchName, err)
 		return
 	}
 	redirectForCommitChoice(ctx, parsed, parsed.form.TreePath)