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>

Author: zeripath

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 != nil {
+	if err := scanner.Err(); 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)
+	}
+}