devapp: automatically deduce current milestone for burndown chart

Use information from maintner to figure out the current development
milestone, and estimate the start of work based on the current six-
month cycle. It should work well enough for now, and can be changed
as needed.

This way it's no longer necessary to manually update the current
milestone and its date every 6 months, as was previously done in
CLs 295191, 248157, 228110, and 193877. Hooray for gophers doing
more of the work for us!

Change-Id: I10b569da577e638a190886c7678f6da1107fdb46
Reviewed-on: https://go-review.googlesource.com/c/build/+/344089
Trust: Dmitri Shuralyov <[email protected]>
Reviewed-by: Carlos Amedee <[email protected]>

Author: dmitshur

devapp/release.go

@@ -18,21 +18,16 @@ import (
 	"time"
 
 	"golang.org/x/build/maintner"
+	"golang.org/x/build/maintner/maintnerd/maintapi/version"
 )
 
 const (
 	labelProposal = "Proposal"
 
 	prefixProposal = "proposal:"
 	prefixDev      = "[dev."
-
-	// The title of the current release milestone in GitHub.
-	curMilestoneTitle = "Go1.17"
 )
 
-// The start date of the current release milestone.
-var curMilestoneStart = time.Date(2021, 2, 22, 0, 0, 0, 0, time.UTC)
-
 // titleDirs returns a slice of prefix directories contained in a title. For
 // devapp,maintner: my cool new change, it will return ["devapp", "maintner"].
 // If there is no dir prefix, it will return nil.
@@ -71,6 +66,7 @@ type releaseData struct {
 	LastUpdated  string
 	Sections     []section
 	BurndownJSON template.JS
+	CurMilestone string // The title of the current release milestone in GitHub. For example, "Go1.18".
 
 	// dirty is set if this data needs to be updated due to a corpus change.
 	dirty bool
@@ -100,10 +96,6 @@ func (i *item) ReleaseBlocker() bool {
 	return i.Issue.HasLabel("release-blocker")
 }
 
-func (i *item) CurrentBlocker() bool {
-	return i.Issue.Milestone.Title == curMilestoneTitle && i.ReleaseBlocker()
-}
-
 func (i *item) EarlyInCycle() bool {
 	return !i.ReleaseBlocker() && i.Issue.HasLabel("early-in-cycle")
 }
@@ -253,6 +245,25 @@ func (s *server) updateReleaseData() {
 		return nil
 	})
 
+	// Determine current milestone based on the highest go1.X tag.
+	var highestGo1X int
+	s.proj.ForeachNonChangeRef(func(ref string, _ maintner.GitHash) error {
+		if !strings.HasPrefix(ref, "refs/tags/go1.") {
+			return nil
+		}
+		tagName := ref[len("refs/tags/"):]
+		if _, x, _, ok := version.ParseTag(tagName); ok && x > highestGo1X {
+			highestGo1X = x
+		}
+		return nil
+	})
+	// The title of the current release milestone in GitHub. For example, "Go1.18".
+	curMilestoneTitle := fmt.Sprintf("Go1.%d", highestGo1X+1)
+	// The start date of the current release milestone, approximated by taking the
+	// Go 1.17 release date, and adding 6 months for each successive major release.
+	var monthsSinceGo117Release = time.Month(6 * (highestGo1X - 17))
+	curMilestoneStart := time.Date(2021, time.August+monthsSinceGo117Release, 1, 0, 0, 0, 0, time.UTC)
+
 	dirToIssues := map[string][]*maintner.GitHubIssue{}
 	var curMilestoneIssues []*maintner.GitHubIssue
 	s.repo.ForeachIssue(func(issue *maintner.GitHubIssue) error {
@@ -307,6 +318,7 @@ func (s *server) updateReleaseData() {
 	s.appendPendingCLs(dirToCLs)
 	s.appendPendingProposals(issueToCLs)
 	s.appendClosedIssues()
+	s.data.release.CurMilestone = curMilestoneTitle
 	s.data.release.LastUpdated = time.Now().UTC().Format(time.UnixDate)
 	s.data.release.dirty = false
 }

devapp/server.go

@@ -33,7 +33,8 @@ type server struct {
 
 	cMu              sync.RWMutex // Used to protect the fields below.
 	corpus           *maintner.Corpus
-	repo             *maintner.GitHubRepo
+	repo             *maintner.GitHubRepo    // The golang/go repo.
+	proj             *maintner.GerritProject // The go.googlesource.com/go project.
 	helpWantedIssues []issueData
 	data             pageData
 
@@ -97,10 +98,14 @@ func (s *server) initCorpus(ctx context.Context) error {
 		return fmt.Errorf("godata.Get: %v", err)
 	}
 	s.corpus = corpus
-	s.repo = s.corpus.GitHub().Repo("golang", "go") // The golang/go repo.
+	s.repo = s.corpus.GitHub().Repo("golang", "go")
 	if s.repo == nil {
 		return fmt.Errorf(`s.corpus.GitHub().Repo("golang", "go") = nil`)
 	}
+	s.proj = s.corpus.Gerrit().Project("go.googlesource.com", "go")
+	if s.proj == nil {
+		return fmt.Errorf(`s.corpus.Gerrit().Project("go.googlesource.com", "go") = nil`)
+	}
 	return nil
 }
 

devapp/templates/release.tmpl

@@ -80,11 +80,12 @@ a:visited {
     {{range .Groups}}
       {{if .Dir}}<h4 class="DirTitle">{{.Dir}}</h4>{{end}}
       {{range .Items}}
-	{{if .FirstPerformance}}<h5 class="Performance-separator">performance</h5>{{end}}
+        {{if .FirstPerformance}}<h5 class="Performance-separator">performance</h5>{{end}}
         {{$i := .Issue}}
         {{if $i}}
           <div class="Item">
-            {{if .CurrentBlocker}}
+            {{$currentBlocker := and (eq .Issue.Milestone.Title $.CurMilestone) .ReleaseBlocker}}
+            {{if $currentBlocker}}
               <div class="Mark" title="{{.Issue.Milestone.Title}} release blocker">★</div>
             {{else if .ReleaseBlocker}}
               <div class="Mark" title="Release blocker">✩</div>