feat(third_party): Check in git-appraise r/10

1 files changed, 772 insertions, 0 deletions

diff --git a/third_party/go/git-appraise/review/review.go b/third_party/go/git-appraise/review/review.go
new file mode 100644
index 000000000000..a23dd17bf798
--- /dev/null
+++ b/third_party/go/git-appraise/review/review.go
@@ -0,0 +1,772 @@
+/*
+Copyright 2015 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package review contains the data structures used to represent code reviews.
+package review
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"sort"
+
+	"github.com/google/git-appraise/repository"
+	"github.com/google/git-appraise/review/analyses"
+	"github.com/google/git-appraise/review/ci"
+	"github.com/google/git-appraise/review/comment"
+	"github.com/google/git-appraise/review/gpg"
+	"github.com/google/git-appraise/review/request"
+)
+
+const archiveRef = "refs/devtools/archives/reviews"
+
+// CommentThread represents the tree-based hierarchy of comments.
+//
+// The Resolved field represents the aggregate status of the entire thread. If
+// it is set to false, then it indicates that there is an unaddressed comment
+// in the thread. If it is unset, then that means that the root comment is an
+// FYI only, and that there are no unaddressed comments. If it is set to true,
+// then that means that there are no unaddressed comments, and that the root
+// comment has its resolved bit set to true.
+type CommentThread struct {
+	Hash     string             `json:"hash,omitempty"`
+	Comment  comment.Comment    `json:"comment"`
+	Original *comment.Comment   `json:"original,omitempty"`
+	Edits    []*comment.Comment `json:"edits,omitempty"`
+	Children []CommentThread    `json:"children,omitempty"`
+	Resolved *bool              `json:"resolved,omitempty"`
+	Edited   bool               `json:"edited,omitempty"`
+}
+
+// Summary represents the high-level state of a code review.
+//
+// This high-level state corresponds to the data that can be quickly read
+// directly from the repo, so other methods that need to operate on a lot
+// of reviews (such as listing the open reviews) should prefer operating on
+// the summary rather than the details.
+//
+// Review summaries have two status fields which are orthogonal:
+// 1. Resolved indicates if a reviewer has accepted or rejected the change.
+// 2. Submitted indicates if the change has been incorporated into the target.
+type Summary struct {
+	Repo        repository.Repo   `json:"-"`
+	Revision    string            `json:"revision"`
+	Request     request.Request   `json:"request"`
+	AllRequests []request.Request `json:"-"`
+	Comments    []CommentThread   `json:"comments,omitempty"`
+	Resolved    *bool             `json:"resolved,omitempty"`
+	Submitted   bool              `json:"submitted"`
+}
+
+// Review represents the entire state of a code review.
+//
+// This extends Summary to also include a list of reports for both the
+// continuous integration status, and the static analysis runs. Those reports
+// correspond to either the current commit in the review ref (for pending
+// reviews), or to the last commented-upon commit (for submitted reviews).
+type Review struct {
+	*Summary
+	Reports  []ci.Report       `json:"reports,omitempty"`
+	Analyses []analyses.Report `json:"analyses,omitempty"`
+}
+
+type commentsByTimestamp []*comment.Comment
+
+// Interface methods for sorting comment threads by timestamp
+func (cs commentsByTimestamp) Len() int      { return len(cs) }
+func (cs commentsByTimestamp) Swap(i, j int) { cs[i], cs[j] = cs[j], cs[i] }
+func (cs commentsByTimestamp) Less(i, j int) bool {
+	return cs[i].Timestamp < cs[j].Timestamp
+}
+
+type byTimestamp []CommentThread
+
+// Interface methods for sorting comment threads by timestamp
+func (threads byTimestamp) Len() int      { return len(threads) }
+func (threads byTimestamp) Swap(i, j int) { threads[i], threads[j] = threads[j], threads[i] }
+func (threads byTimestamp) Less(i, j int) bool {
+	return threads[i].Comment.Timestamp < threads[j].Comment.Timestamp
+}
+
+type requestsByTimestamp []request.Request
+
+// Interface methods for sorting review requests by timestamp
+func (requests requestsByTimestamp) Len() int { return len(requests) }
+func (requests requestsByTimestamp) Swap(i, j int) {
+	requests[i], requests[j] = requests[j], requests[i]
+}
+func (requests requestsByTimestamp) Less(i, j int) bool {
+	return requests[i].Timestamp < requests[j].Timestamp
+}
+
+type summariesWithNewestRequestsFirst []Summary
+
+// Interface methods for sorting review summaries in reverse chronological order
+func (summaries summariesWithNewestRequestsFirst) Len() int { return len(summaries) }
+func (summaries summariesWithNewestRequestsFirst) Swap(i, j int) {
+	summaries[i], summaries[j] = summaries[j], summaries[i]
+}
+func (summaries summariesWithNewestRequestsFirst) Less(i, j int) bool {
+	return summaries[i].Request.Timestamp > summaries[j].Request.Timestamp
+}
+
+// updateThreadsStatus calculates the aggregate status of a sequence of comment threads.
+//
+// The aggregate status is the conjunction of all of the non-nil child statuses.
+//
+// This has the side-effect of setting the "Resolved" field of all descendant comment threads.
+func updateThreadsStatus(threads []CommentThread) *bool {
+	sort.Stable(byTimestamp(threads))
+	noUnresolved := true
+	var result *bool
+	for i := range threads {
+		thread := &threads[i]
+		thread.updateResolvedStatus()
+		if thread.Resolved != nil {
+			noUnresolved = noUnresolved && *thread.Resolved
+			result = &noUnresolved
+		}
+	}
+	return result
+}
+
+// updateResolvedStatus calculates the aggregate status of a single comment thread,
+// and updates the "Resolved" field of that thread accordingly.
+func (thread *CommentThread) updateResolvedStatus() {
+	resolved := updateThreadsStatus(thread.Children)
+	if resolved == nil {
+		thread.Resolved = thread.Comment.Resolved
+		return
+	}
+
+	if !*resolved {
+		thread.Resolved = resolved
+		return
+	}
+
+	if thread.Comment.Resolved == nil || !*thread.Comment.Resolved {
+		thread.Resolved = nil
+		return
+	}
+
+	thread.Resolved = resolved
+}
+
+// Verify verifies the signature on a comment.
+func (thread *CommentThread) Verify() error {
+	err := gpg.Verify(&thread.Comment)
+	if err != nil {
+		hash, _ := thread.Comment.Hash()
+		return fmt.Errorf("verification of comment [%s] failed: %s", hash, err)
+	}
+	for _, child := range thread.Children {
+		err = child.Verify()
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// mutableThread is an internal-only data structure used to store partially constructed comment threads.
+type mutableThread struct {
+	Hash     string
+	Comment  comment.Comment
+	Edits    []*comment.Comment
+	Children []*mutableThread
+}
+
+// fixMutableThread is a helper method to finalize a mutableThread struct
+// (partially constructed comment thread) as a CommentThread struct
+// (fully constructed comment thread).
+func fixMutableThread(mutableThread *mutableThread) CommentThread {
+	var children []CommentThread
+	edited := len(mutableThread.Edits) > 0
+	for _, mutableChild := range mutableThread.Children {
+		child := fixMutableThread(mutableChild)
+		if (!edited) && child.Edited {
+			edited = true
+		}
+		children = append(children, child)
+	}
+	comment := &mutableThread.Comment
+	if len(mutableThread.Edits) > 0 {
+		sort.Stable(commentsByTimestamp(mutableThread.Edits))
+		comment = mutableThread.Edits[len(mutableThread.Edits)-1]
+	}
+
+	return CommentThread{
+		Hash:     mutableThread.Hash,
+		Comment:  *comment,
+		Original: &mutableThread.Comment,
+		Edits:    mutableThread.Edits,
+		Children: children,
+		Edited:   edited,
+	}
+}
+
+// This function builds the comment thread tree from the log-based list of comments.
+//
+// Since the comments can be processed in any order, this uses an internal mutable
+// data structure, and then converts it to the proper CommentThread structure at the end.
+func buildCommentThreads(commentsByHash map[string]comment.Comment) []CommentThread {
+	threadsByHash := make(map[string]*mutableThread)
+	for hash, comment := range commentsByHash {
+		thread, ok := threadsByHash[hash]
+		if !ok {
+			thread = &mutableThread{
+				Hash:    hash,
+				Comment: comment,
+			}
+			threadsByHash[hash] = thread
+		}
+	}
+	var rootHashes []string
+	for hash, thread := range threadsByHash {
+		if thread.Comment.Original != "" {
+			original, ok := threadsByHash[thread.Comment.Original]
+			if ok {
+				original.Edits = append(original.Edits, &thread.Comment)
+			}
+		} else if thread.Comment.Parent == "" {
+			rootHashes = append(rootHashes, hash)
+		} else {
+			parent, ok := threadsByHash[thread.Comment.Parent]
+			if ok {
+				parent.Children = append(parent.Children, thread)
+			}
+		}
+	}
+	var threads []CommentThread
+	for _, hash := range rootHashes {
+		threads = append(threads, fixMutableThread(threadsByHash[hash]))
+	}
+	return threads
+}
+
+// loadComments reads in the log-structured sequence of comments for a review,
+// and then builds the corresponding tree-structured comment threads.
+func (r *Summary) loadComments(commentNotes []repository.Note) []CommentThread {
+	commentsByHash := comment.ParseAllValid(commentNotes)
+	return buildCommentThreads(commentsByHash)
+}
+
+func getSummaryFromNotes(repo repository.Repo, revision string, requestNotes, commentNotes []repository.Note) (*Summary, error) {
+	requests := request.ParseAllValid(requestNotes)
+	if requests == nil {
+		return nil, fmt.Errorf("Could not find any review requests for %q", revision)
+	}
+	sort.Stable(requestsByTimestamp(requests))
+	reviewSummary := Summary{
+		Repo:        repo,
+		Revision:    revision,
+		Request:     requests[len(requests)-1],
+		AllRequests: requests,
+	}
+	reviewSummary.Comments = reviewSummary.loadComments(commentNotes)
+	reviewSummary.Resolved = updateThreadsStatus(reviewSummary.Comments)
+	return &reviewSummary, nil
+}
+
+// GetSummary returns the summary of the code review specified by its revision
+// and the references which contain that reviews summary and comments.
+//
+// If no review request exists, the returned review summary is nil.
+func GetSummaryViaRefs(repo repository.Repo, requestRef, commentRef,
+	revision string) (*Summary, error) {
+
+	if err := repo.VerifyCommit(revision); err != nil {
+		return nil, fmt.Errorf("Could not find a commit named %q", revision)
+	}
+	requestNotes := repo.GetNotes(requestRef, revision)
+	commentNotes := repo.GetNotes(commentRef, revision)
+	summary, err := getSummaryFromNotes(repo, revision, requestNotes, commentNotes)
+	if err != nil {
+		return nil, err
+	}
+	currentCommit := revision
+	if summary.Request.Alias != "" {
+		currentCommit = summary.Request.Alias
+	}
+
+	if !summary.IsAbandoned() {
+		submitted, err := repo.IsAncestor(currentCommit, summary.Request.TargetRef)
+		if err != nil {
+			return nil, err
+		}
+		summary.Submitted = submitted
+	}
+	return summary, nil
+}
+
+// GetSummary returns the summary of the specified code review.
+//
+// If no review request exists, the returned review summary is nil.
+func GetSummary(repo repository.Repo, revision string) (*Summary, error) {
+	return GetSummaryViaRefs(repo, request.Ref, comment.Ref, revision)
+}
+
+// Details returns the detailed review for the given summary.
+func (r *Summary) Details() (*Review, error) {
+	review := Review{
+		Summary: r,
+	}
+	currentCommit, err := review.GetHeadCommit()
+	if err == nil {
+		review.Reports = ci.ParseAllValid(review.Repo.GetNotes(ci.Ref, currentCommit))
+		review.Analyses = analyses.ParseAllValid(review.Repo.GetNotes(analyses.Ref, currentCommit))
+	}
+	return &review, nil
+}
+
+// IsAbandoned returns whether or not the given review has been abandoned.
+func (r *Summary) IsAbandoned() bool {
+	return r.Request.TargetRef == ""
+}
+
+// IsOpen returns whether or not the given review is still open (neither submitted nor abandoned).
+func (r *Summary) IsOpen() bool {
+	return !r.Submitted && !r.IsAbandoned()
+}
+
+// Verify returns whether or not a summary's comments are a) signed, and b)
+/// that those signatures are verifiable.
+func (r *Summary) Verify() error {
+	err := gpg.Verify(&r.Request)
+	if err != nil {
+		return fmt.Errorf("couldn't verify request targeting: %q: %s",
+			r.Request.TargetRef, err)
+	}
+	for _, thread := range r.Comments {
+		err := thread.Verify()
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// Get returns the specified code review.
+//
+// If no review request exists, the returned review is nil.
+func Get(repo repository.Repo, revision string) (*Review, error) {
+	summary, err := GetSummary(repo, revision)
+	if err != nil {
+		return nil, err
+	}
+	if summary == nil {
+		return nil, nil
+	}
+	return summary.Details()
+}
+
+func getIsSubmittedCheck(repo repository.Repo) func(ref, commit string) bool {
+	refCommitsMap := make(map[string]map[string]bool)
+
+	getRefCommitsMap := func(ref string) map[string]bool {
+		commitsMap, ok := refCommitsMap[ref]
+		if ok {
+			return commitsMap
+		}
+		commitsMap = make(map[string]bool)
+		for _, commit := range repo.ListCommits(ref) {
+			commitsMap[commit] = true
+		}
+		refCommitsMap[ref] = commitsMap
+		return commitsMap
+	}
+
+	return func(ref, commit string) bool {
+		return getRefCommitsMap(ref)[commit]
+	}
+}
+
+func unsortedListAll(repo repository.Repo) []Summary {
+	reviewNotesMap, err := repo.GetAllNotes(request.Ref)
+	if err != nil {
+		return nil
+	}
+	discussNotesMap, err := repo.GetAllNotes(comment.Ref)
+	if err != nil {
+		return nil
+	}
+
+	isSubmittedCheck := getIsSubmittedCheck(repo)
+	var reviews []Summary
+	for commit, notes := range reviewNotesMap {
+		summary, err := getSummaryFromNotes(repo, commit, notes, discussNotesMap[commit])
+		if err != nil {
+			continue
+		}
+		if !summary.IsAbandoned() {
+			summary.Submitted = isSubmittedCheck(summary.Request.TargetRef, summary.getStartingCommit())
+		}
+		reviews = append(reviews, *summary)
+	}
+	return reviews
+}
+
+// ListAll returns all reviews stored in the git-notes.
+func ListAll(repo repository.Repo) []Summary {
+	reviews := unsortedListAll(repo)
+	sort.Stable(summariesWithNewestRequestsFirst(reviews))
+	return reviews
+}
+
+// ListOpen returns all reviews that are not yet incorporated into their target refs.
+func ListOpen(repo repository.Repo) []Summary {
+	var openReviews []Summary
+	for _, review := range unsortedListAll(repo) {
+		if review.IsOpen() {
+			openReviews = append(openReviews, review)
+		}
+	}
+	sort.Stable(summariesWithNewestRequestsFirst(openReviews))
+	return openReviews
+}
+
+// GetCurrent returns the current, open code review.
+//
+// If there are multiple matching reviews, then an error is returned.
+func GetCurrent(repo repository.Repo) (*Review, error) {
+	reviewRef, err := repo.GetHeadRef()
+	if err != nil {
+		return nil, err
+	}
+	var matchingReviews []Summary
+	for _, review := range ListOpen(repo) {
+		if review.Request.ReviewRef == reviewRef {
+			matchingReviews = append(matchingReviews, review)
+		}
+	}
+	if matchingReviews == nil {
+		return nil, nil
+	}
+	if len(matchingReviews) != 1 {
+		return nil, fmt.Errorf("There are %d open reviews for the ref \"%s\"", len(matchingReviews), reviewRef)
+	}
+	return matchingReviews[0].Details()
+}
+
+// GetBuildStatusMessage returns a string of the current build-and-test status
+// of the review, or "unknown" if the build-and-test status cannot be determined.
+func (r *Review) GetBuildStatusMessage() string {
+	statusMessage := "unknown"
+	ciReport, err := ci.GetLatestCIReport(r.Reports)
+	if err != nil {
+		return fmt.Sprintf("unknown: %s", err)
+	}
+	if ciReport != nil {
+		statusMessage = fmt.Sprintf("%s (%q)", ciReport.Status, ciReport.URL)
+	}
+	return statusMessage
+}
+
+// GetAnalysesNotes returns all of the notes from the most recent static
+// analysis run recorded in the git notes.
+func (r *Review) GetAnalysesNotes() ([]analyses.Note, error) {
+	latestAnalyses, err := analyses.GetLatestAnalysesReport(r.Analyses)
+	if err != nil {
+		return nil, err
+	}
+	if latestAnalyses == nil {
+		return nil, fmt.Errorf("No analyses available")
+	}
+	return latestAnalyses.GetNotes()
+}
+
+// GetAnalysesMessage returns a string summarizing the results of the
+// most recent static analyses.
+func (r *Review) GetAnalysesMessage() string {
+	latestAnalyses, err := analyses.GetLatestAnalysesReport(r.Analyses)
+	if err != nil {
+		return err.Error()
+	}
+	if latestAnalyses == nil {
+		return "No analyses available"
+	}
+	status := latestAnalyses.Status
+	if status != "" && status != analyses.StatusNeedsMoreWork {
+		return status
+	}
+	analysesNotes, err := latestAnalyses.GetNotes()
+	if err != nil {
+		return err.Error()
+	}
+	if analysesNotes == nil {
+		return "passed"
+	}
+	return fmt.Sprintf("%d warnings\n", len(analysesNotes))
+	// TODO(ojarjur): Figure out the best place to display the actual notes
+}
+
+func prettyPrintJSON(jsonBytes []byte) (string, error) {
+	var prettyBytes bytes.Buffer
+	err := json.Indent(&prettyBytes, jsonBytes, "", "  ")
+	if err != nil {
+		return "", err
+	}
+	return prettyBytes.String(), nil
+}
+
+// GetJSON returns the pretty printed JSON for a review summary.
+func (r *Summary) GetJSON() (string, error) {
+	jsonBytes, err := json.Marshal(*r)
+	if err != nil {
+		return "", err
+	}
+	return prettyPrintJSON(jsonBytes)
+}
+
+// GetJSON returns the pretty printed JSON for a review.
+func (r *Review) GetJSON() (string, error) {
+	jsonBytes, err := json.Marshal(*r)
+	if err != nil {
+		return "", err
+	}
+	return prettyPrintJSON(jsonBytes)
+}
+
+// findLastCommit returns the later (newest) commit from the union of the provided commit
+// and all of the commits that are referenced in the given comment threads.
+func (r *Review) findLastCommit(startingCommit, latestCommit string, commentThreads []CommentThread) string {
+	isLater := func(commit string) bool {
+		if err := r.Repo.VerifyCommit(commit); err != nil {
+			return false
+		}
+		if t, e := r.Repo.IsAncestor(latestCommit, commit); e == nil && t {
+			return true
+		}
+		if t, e := r.Repo.IsAncestor(startingCommit, commit); e == nil && !t {
+			return false
+		}
+		if t, e := r.Repo.IsAncestor(commit, latestCommit); e == nil && t {
+			return false
+		}
+		ct, err := r.Repo.GetCommitTime(commit)
+		if err != nil {
+			return false
+		}
+		lt, err := r.Repo.GetCommitTime(latestCommit)
+		if err != nil {
+			return true
+		}
+		return ct > lt
+	}
+	updateLatest := func(commit string) {
+		if commit == "" {
+			return
+		}
+		if isLater(commit) {
+			latestCommit = commit
+		}
+	}
+	for _, commentThread := range commentThreads {
+		comment := commentThread.Comment
+		if comment.Location != nil {
+			updateLatest(comment.Location.Commit)
+		}
+		updateLatest(r.findLastCommit(startingCommit, latestCommit, commentThread.Children))
+	}
+	return latestCommit
+}
+
+func (r *Summary) getStartingCommit() string {
+	if r.Request.Alias != "" {
+		return r.Request.Alias
+	}
+	return r.Revision
+}
+
+// GetHeadCommit returns the latest commit in a review.
+func (r *Review) GetHeadCommit() (string, error) {
+	currentCommit := r.getStartingCommit()
+	if r.Request.ReviewRef == "" {
+		return currentCommit, nil
+	}
+
+	if r.Submitted {
+		// The review has already been submitted.
+		// Go through the list of comments and find the last commented upon commit.
+		return r.findLastCommit(currentCommit, currentCommit, r.Comments), nil
+	}
+
+	// It is possible that the review ref is no longer an ancestor of the starting
+	// commit (e.g. if a rebase left us in a detached head), in which case we have to
+	// find the head commit without using it.
+	useReviewRef, err := r.Repo.IsAncestor(currentCommit, r.Request.ReviewRef)
+	if err != nil {
+		return "", err
+	}
+	if useReviewRef {
+		return r.Repo.ResolveRefCommit(r.Request.ReviewRef)
+	}
+
+	return r.findLastCommit(currentCommit, currentCommit, r.Comments), nil
+}
+
+// GetBaseCommit returns the commit against which a review should be compared.
+func (r *Review) GetBaseCommit() (string, error) {
+	if !r.IsOpen() {
+		if r.Request.BaseCommit != "" {
+			return r.Request.BaseCommit, nil
+		}
+
+		// This means the review has been submitted, but did not specify a base commit.
+		// In this case, we have to treat the last parent commit as the base. This is
+		// usually what we want, since merging a target branch into a feature branch
+		// results in the previous commit to the feature branch being the first parent,
+		// and the latest commit to the target branch being the second parent.
+		return r.Repo.GetLastParent(r.Revision)
+	}
+
+	targetRefHead, err := r.Repo.ResolveRefCommit(r.Request.TargetRef)
+	if err != nil {
+		return "", err
+	}
+	leftHandSide := targetRefHead
+	rightHandSide := r.Revision
+	if r.Request.ReviewRef != "" {
+		if reviewRefHead, err := r.Repo.ResolveRefCommit(r.Request.ReviewRef); err == nil {
+			rightHandSide = reviewRefHead
+		}
+	}
+
+	return r.Repo.MergeBase(leftHandSide, rightHandSide)
+}
+
+// ListCommits lists the commits included in a review.
+func (r *Review) ListCommits() ([]string, error) {
+	baseCommit, err := r.GetBaseCommit()
+	if err != nil {
+		return nil, err
+	}
+	headCommit, err := r.GetHeadCommit()
+	if err != nil {
+		return nil, err
+	}
+	return r.Repo.ListCommitsBetween(baseCommit, headCommit)
+}
+
+// GetDiff returns the diff for a review.
+func (r *Review) GetDiff(diffArgs ...string) (string, error) {
+	var baseCommit, headCommit string
+	baseCommit, err := r.GetBaseCommit()
+	if err == nil {
+		headCommit, err = r.GetHeadCommit()
+	}
+	if err == nil {
+		return r.Repo.Diff(baseCommit, headCommit, diffArgs...)
+	}
+	return "", err
+}
+
+// AddComment adds the given comment to the review.
+func (r *Review) AddComment(c comment.Comment) error {
+	commentNote, err := c.Write()
+	if err != nil {
+		return err
+	}
+
+	r.Repo.AppendNote(comment.Ref, r.Revision, commentNote)
+	return nil
+}
+
+// Rebase performs an interactive rebase of the review onto its target ref.
+//
+// If the 'archivePrevious' argument is true, then the previous head of the
+// review will be added to the 'refs/devtools/archives/reviews' ref prior
+// to being rewritten. That ensures the review history is kept from being
+// garbage collected.
+func (r *Review) Rebase(archivePrevious bool) error {
+	if archivePrevious {
+		orig, err := r.GetHeadCommit()
+		if err != nil {
+			return err
+		}
+		if err := r.Repo.ArchiveRef(orig, archiveRef); err != nil {
+			return err
+		}
+	}
+	if err := r.Repo.SwitchToRef(r.Request.ReviewRef); err != nil {
+		return err
+	}
+
+	err := r.Repo.RebaseRef(r.Request.TargetRef)
+	if err != nil {
+		return err
+	}
+
+	alias, err := r.Repo.GetCommitHash("HEAD")
+	if err != nil {
+		return err
+	}
+	r.Request.Alias = alias
+	newNote, err := r.Request.Write()
+	if err != nil {
+		return err
+	}
+	return r.Repo.AppendNote(request.Ref, r.Revision, newNote)
+}
+
+// RebaseAndSign performs an interactive rebase of the review onto its
+// target ref. It signs the result of the rebase as well as (re)signs
+// the review request itself.
+//
+// If the 'archivePrevious' argument is true, then the previous head of the
+// review will be added to the 'refs/devtools/archives/reviews' ref prior
+// to being rewritten. That ensures the review history is kept from being
+// garbage collected.
+func (r *Review) RebaseAndSign(archivePrevious bool) error {
+	if archivePrevious {
+		orig, err := r.GetHeadCommit()
+		if err != nil {
+			return err
+		}
+		if err := r.Repo.ArchiveRef(orig, archiveRef); err != nil {
+			return err
+		}
+	}
+	if err := r.Repo.SwitchToRef(r.Request.ReviewRef); err != nil {
+		return err
+	}
+
+	err := r.Repo.RebaseAndSignRef(r.Request.TargetRef)
+	if err != nil {
+		return err
+	}
+
+	alias, err := r.Repo.GetCommitHash("HEAD")
+	if err != nil {
+		return err
+	}
+	r.Request.Alias = alias
+
+	key, err := r.Repo.GetUserSigningKey()
+	if err != nil {
+		return err
+	}
+	err = gpg.Sign(key, &r.Request)
+	if err != nil {
+		return err
+	}
+
+	newNote, err := r.Request.Write()
+	if err != nil {
+		return err
+	}
+	return r.Repo.AppendNote(request.Ref, r.Revision, newNote)
+}