The begin bound of a run ask is the checker's setting; a dropped run ask and a program that does not build fail the whole check naming the program (issue 1921)

Claude-Session: https://claude.ai/code/session_01NcbgfFSnn24M3GcqttoU7i

modules/mesh-delivery-checker/cmd/mesh-delivery-checker/integration_test.go

@@ -98,6 +98,30 @@ type fakeBuildModules struct {
 	inputs jetstream.KeyValue
 	runs   atomic.Int32
 	broken atomic.Value
+	// drop, when set, drops every run ask unanswered and counts it in dropped, as a build module that does not know the job
+	// run (the lead's ruling on milestone 47/B0).
+	drop    atomic.Bool
+	dropped atomic.Int32
+}
+
+// droppingAsks is the seat's asks as a build module that does not know the job run takes them: a run ask is acknowledged and
+// never begun while the fake drops them.
+type droppingAsks struct {
+	gobuild.AskSource
+	f *fakeBuildModules
+}
+
+func (d droppingAsks) Next(ctx context.Context, kind string, wait time.Duration) (*gobuild.Pulled, error) {
+	msg, err := d.AskSource.Next(ctx, kind, wait)
+	if err != nil || msg == nil || !d.f.drop.Load() {
+		return msg, err
+	}
+	var a delivery.StepAsk
+	if json.Unmarshal(msg.Data, &a) == nil && a.Run != nil {
+		d.f.dropped.Add(1)
+		return nil, msg.Ack()
+	}
+	return msg, nil
 }
 
 // run answers a run ask as mesh-build-go does: the checking program's work (rules.Program) over the input the ask names,
@@ -220,7 +244,7 @@ func (f *fakeBuildModules) serve(t *testing.T, module string, kept jetstream.Key
 		raw, _ := value.(json.RawMessage)
 		return kv.Put(f.ctx, key, raw)
 	}
-	p := &gobuild.Puller{Source: &gobuild.JetStreamAsks{JS: f.js, Language: language}, Language: language, Node: "n1", Put: put,
+	p := &gobuild.Puller{Source: droppingAsks{&gobuild.JetStreamAsks{JS: f.js, Language: language}, f}, Language: language, Node: "n1", Put: put,
 		Capacity: func() int { return 2 }, PullWait: 200 * time.Millisecond,
 		Run: func(ctx context.Context, a delivery.StepAsk) (any, error) {
 			if a.Check != nil {
@@ -792,28 +816,54 @@ func keptCount(t *testing.T, b *bed) int {
 	return len(keys)
 }
 
-// TestAHeadThatDoesNotMergeFailsNamingTheFilesAndRunsNoTest: the fetch answers the files in conflict; the verdict fails naming
-// them, no test or digest step is run, a preview of the conflicts alone is written and the status is owed as failure.
-func TestAHeadThatDoesNotMergeFailsNamingTheFilesAndRunsNoTest(t *testing.T) { // 1289/AC4
-	b := startBed(t)
-	b.fake.conflict.Store(true)
-	key := b.candidate(t, "feat/x", pull(repo, 7, head1))
-	b.start(t, nil)
-	v := b.verdict(t, key, ended)
-	if v.State != delivery.VerdictFail || !strings.Contains(v.Failed.Words, "files in conflict: a.go, sub/b.go") {
-		t.Fatalf("verdict = %+v", v)
-	}
-	if o := b.owed(t, 7, head1, "failure"); !strings.HasPrefix(o.Text, "failed: n1: ") || !strings.Contains(o.Text, "files in conflict: a.go, sub/b.go") {
-		t.Errorf("owed = %+v", o)
-	}
-	if n := b.fake.count("mesh-build-go.build_go_digest") + b.fake.count("mesh-build-go.build_go_test"); n != 0 {
-		t.Errorf("%d digest and test steps ran after a conflict", n)
-	}
-	pk, _ := delivery.PreviewKey(repo, head1, trunk)
-	if e, err := b.buckets[delivery.PreviewsBucket].Get(b.ctx, pk); err != nil {
-		t.Errorf("previews.%s: %v", pk, err)
-	} else if pv, err := delivery.DecodePreview(e.Value()); err != nil || strings.Join(pv.Conflicts, ",") != "a.go,sub/b.go" || pv.Merge != "" {
-		t.Errorf("preview = %+v, %v, want the files in conflict alone", pv, err)
+// TestACheckThatCannotBeJudgedFailsNamingWhy: a head that does not merge fails naming the files in conflict and runs no
+// test (1289/AC4); a checking program whose run asks no build node begins, and one that does not build, fail the check
+// naming the checking program, never judged by the running rules (issue 1921, the lead's ruling on milestone 47/B0: the
+// begin bound is the checker's setting, shortened here).
+func TestACheckThatCannotBeJudgedFailsNamingWhy(t *testing.T) { // 1289/AC4, 1921
+	for _, row := range []struct {
+		name    string
+		set     func(f *fakeBuildModules)
+		env     map[string]string
+		words   string
+		tests   bool  // the digest and test steps ran
+		dropped int32 // the run asks dropped: each put twice, the seat list's and the verdict's
+		program bool  // the checking program judged it
+	}{
+		{name: "a head that does not merge", set: func(f *fakeBuildModules) { f.conflict.Store(true) }, words: "files in conflict: a.go, sub/b.go", program: true},
+		{name: "a run ask no build node begins", set: func(f *fakeBuildModules) { f.drop.Store(true) }, env: map[string]string{"MESH_CHECKER_BEGIN_BOUND": "500ms"},
+			words: "no build node began the job run of the asks", tests: true, dropped: 4},
+		{name: "a program that does not build", set: func(f *fakeBuildModules) { f.broken.Store("go build: undefined: rules.Nothing") },
+			words: "by the checking program: its run ask", tests: true},
+	} {
+		t.Run(row.name, func(t *testing.T) {
+			b := startBed(t)
+			row.set(b.fake)
+			key := b.candidate(t, "feat/x", pull(repo, 7, head1))
+			b.start(t, row.env)
+			v := b.verdict(t, key, ended)
+			if v.State != delivery.VerdictFail || !strings.Contains(v.Failed.Words, row.words) || (v.JudgedBy != nil) != row.program {
+				t.Fatalf("verdict = %+v, want a fail saying %q, judged by the program %v", v, row.words, row.program)
+			}
+			if o := b.owed(t, 7, head1, "failure"); !strings.HasPrefix(o.Text, "failed") ||
+				!strings.Contains(o.Text, map[bool]string{true: row.words, false: "the checking program"}[row.program]) {
+				t.Errorf("owed = %+v", o)
+			}
+			if n := b.fake.count("mesh-build-go.build_go_digest") + b.fake.count("mesh-build-go.build_go_test"); (n != 0) != row.tests {
+				t.Errorf("%d digest and test steps ran, want them run %v", n, row.tests)
+			}
+			if n := b.fake.dropped.Load(); n != row.dropped {
+				t.Errorf("%d run asks dropped, want %d", n, row.dropped)
+			}
+			if !row.tests {
+				pk, _ := delivery.PreviewKey(repo, head1, trunk)
+				if e, err := b.buckets[delivery.PreviewsBucket].Get(b.ctx, pk); err != nil {
+					t.Errorf("previews.%s: %v", pk, err)
+				} else if pv, err := delivery.DecodePreview(e.Value()); err != nil || strings.Join(pv.Conflicts, ",") != "a.go,sub/b.go" || pv.Merge != "" {
+					t.Errorf("preview = %+v, %v, want the files in conflict alone", pv, err)
+				}
+			}
+		})
 	}
 }
 

modules/mesh-delivery-checker/cmd/mesh-delivery-checker/judge.go

@@ -25,12 +25,14 @@ import (
 // judgeDeps are the parts the judge of a check is made of.
 type judgeDeps struct {
 	// inputs keeps the checking program's inputs (check.InputsState).
-	inputs   check.Inputs
-	asks     check.Asks
-	tools    *buildrun.ToolchainSet
-	trunks   *check.Trunks
-	kept     check.KV
-	previews check.KV
+	inputs check.Inputs
+	// beginBound is how long a run ask may wait for a build node to begin it; check.DefaultBeginBound when 0.
+	beginBound time.Duration
+	asks       check.Asks
+	tools      *buildrun.ToolchainSet
+	trunks     *check.Trunks
+	kept       check.KV
+	previews   check.KV
 	// candidates answers the indexer's candidate of a try's group (try_candidates.go); nil leaves a whole try with no
 	// manifest or composition judged, said.
 	candidates check.TryCandidates
@@ -162,7 +164,7 @@ func newJudge(d judgeDeps) check.Judge {
 		nodes = d.nodes
 	}
 	ex := &check.Examiner{Nodes: nodes, Compositions: d.compositions, Asks: d.asks, Toolchains: d.tools,
-		Kept: check.Kept{Store: d.kept}, Previews: d.previews, Candidates: d.candidates, Modules: d.repos, Packages: d.repos, Published: d.published, Forge: d.forge, Runs: d.repos, Builds: d.builds, BuildEnds: d.ends, BuildWait: d.buildWait, Announce: d.announce, Trunks: d.trunks, Manifests: d.repos, Read: d.repos, Predefined: d.predefined, Inputs: d.inputs, Logf: d.logf}
+		Kept: check.Kept{Store: d.kept}, Previews: d.previews, Candidates: d.candidates, Modules: d.repos, Packages: d.repos, Published: d.published, Forge: d.forge, Runs: d.repos, Builds: d.builds, BuildEnds: d.ends, BuildWait: d.buildWait, Announce: d.announce, Trunks: d.trunks, Manifests: d.repos, Read: d.repos, Predefined: d.predefined, Inputs: d.inputs, BeginBound: d.beginBound, Logf: d.logf}
 	if d.nodes != nil && d.builds != nil && d.repos != nil {
 		ex.Serving = runningServes{have: d.nodes, builds: d.builds, read: d.repos, logf: d.logf}
 	}

modules/mesh-delivery-checker/cmd/mesh-delivery-checker/main.go

@@ -128,6 +128,11 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 	if err != nil {
 		return err
 	}
+	// The begin bound of a run ask of the checking program (check.DefaultBeginBound, issue 1921).
+	beginBound, err := durationEnv(getenv, "MESH_CHECKER_BEGIN_BOUND", check.DefaultBeginBound)
+	if err != nil {
+		return err
+	}
 	link := strings.TrimSpace(getenv("MESH_CHECKER_LINK"))
 	if link == "" {
 		link = defaultLink
@@ -230,7 +235,7 @@ func run(ctx context.Context, getenv func(string) string, logOut io.Writer) erro
 		asks: buildrun.Asker{Publisher: asks, Waiter: waiter, Bound: stepBound}, tools: tools, trunks: trunks,
 		kept: kvStore{buckets[delivery.CheckerKeptBucket]}, previews: kvStore{buckets[delivery.PreviewsBucket]}, candidates: tryCandidates{buckets[delivery.CandidatesBucket]},
 		repos: repos, published: published, builds: builds, ends: ends, buildWait: set.buildWait, forge: forgeReads{call: caller.Call}, logf: logger.Printf,
-		announce: announce, compositions: compositions, inputs: runInputs{awaitedKV{inputsKV}},
+		announce: announce, compositions: compositions, inputs: runInputs{awaitedKV{inputsKV}}, beginBound: beginBound,
 		nodes: openNodeNames(ctx, js, logger.Printf),
 		predefined: keptPredefined{process.AwaitBucket(ctx, js, conn, delivery.IndexerModule+"_"+delivery.IndexerPredefinedState,
 			"a change's manifests are judged with no predefined keys, each fallback as its value declares it", logger.Printf)},