mesh-delivery/modules/mesh-delivery-builder/internal/build/run_test.go

package build

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
	"strconv"
	"strings"
	"sync"
	"sync/atomic"
	"testing"
	"time"

	"git.novox.be/novox/mesh-sdk/go/buildstep"
	"git.novox.be/novox/mesh-sdk/go/catalogue"
	"git.novox.be/novox/mesh-sdk/go/delivery"
)

// buildModules simulates the two build modules on the nodes: a long tool answers a step and key at once and writes the
// step's end into the steps (as mesh-build-go and mesh-build-node do), with a digest by node and artifact, or a failure.
type buildModules struct {
	mu      sync.Mutex
	n       int
	calls   []call
	steps   *fakeSteps
	digests map[string]string // `<node>/<artifact>` -> digest; the default is `digest`
	fails   map[string]string // `<node>/<tool>` -> the reason the step fails with
	// noRef names `<node>/<artifact>` whose bundle or archive build answers no reference (its push not answered).
	noRef map[string]bool
	// packages are the package artifacts by name, each with the `<name>@<version>` its trunk build publishes (ADR 0498 clause 5).
	packages map[string]string
	// hold, when set before the builds start, blocks every call until it is closed; entered is sent to as a call arrives.
	// conflicts, when set, is a file a fetch with a base reports in conflict; noMerge makes it answer neither a merge nor a conflict.
	conflicts string
	noMerge   bool
	hold      chan struct{}
	entered   chan struct{}
}

func newBuildModules() *buildModules {
	return &buildModules{steps: &fakeSteps{steps: map[string]delivery.Step{}}, digests: map[string]string{}, fails: map[string]string{}, noRef: map[string]bool{}, packages: map[string]string{}}
}

func (b *buildModules) CallOn(node, key string, body any) (json.RawMessage, error) {
	if b.hold != nil {
		select {
		case b.entered <- struct{}{}:
		default:
		}
		<-b.hold
	}
	b.mu.Lock()
	defer b.mu.Unlock()
	b.calls = append(b.calls, call{node, key, body})
	b.n++
	id := fmt.Sprintf("s%d", b.n)
	module, tool, _ := strings.Cut(key, ".")
	args, _ := body.(map[string]any)
	step := delivery.Step{ID: id, Tool: tool, Node: node, State: delivery.StepPassed}
	if reason, ok := b.fails[node+"/"+tool]; ok {
		step.State, step.Reason = delivery.StepFailed, reason
	} else if strings.HasSuffix(tool, "_fetch") {
		step.Result = json.RawMessage(`{"workspace":"w-` + node + `"}`)
		if args["base"] != nil { // a fetch with a base answers the merge, or the files in conflict (mesh-build-go FetchResult)
			if b.conflicts != "" {
				step.Result = json.RawMessage(`{"workspace":"w-` + node + `","base":"` + fmt.Sprint(args["base"]) + `","conflicts":["` + b.conflicts + `"]}`)
			} else if !b.noMerge {
				step.Result = json.RawMessage(`{"workspace":"w-` + node + `","base":"` + fmt.Sprint(args["base"]) + `","merge":"` + strings.Repeat("9", 40) + `"}`)
			}
		}
	} else {
		d := digest
		if v, ok := b.digests[node+"/"+fmt.Sprint(args["artifact"])]; ok {
			d = v
		}
		if tool == "build_image_copy" { // mesh-build-image's copy answers the digest and where it copied to (ADR 0498 clause 4)
			step.Result = json.RawMessage(`{"artifact":"` + fmt.Sprint(args["artifact"]) + `","digest":"` + d + `","reference":"registry.example/` + fmt.Sprint(args["module"]) + `/` + fmt.Sprint(args["artifact"]) + `@` + d + `","pushed":true}`)
		} else if pkg, ok := b.packages[fmt.Sprint(args["artifact"])]; ok { // a package names its version only when published
			step.Result = json.RawMessage(`{"digest":"` + d + `"}`)
			if args["publish"] == true {
				step.Result = json.RawMessage(`{"digest":"` + d + `","reference":"` + pkg + `"}`)
			}
		} else if tool == "build_image_build" && args["publish"] == true {
			step.Result = json.RawMessage(`{"digest":"` + d + `","reference":"registry.example/m/` + fmt.Sprint(args["artifact"]) + `@` + d + `"}`)
		} else if tool != "build_image_build" && !b.noRef[node+"/"+fmt.Sprint(args["artifact"])] {
			// A bundle or an archive is pushed to the artifact store and its reference answered (ADR 0498 clause 1).
			step.Result = json.RawMessage(`{"digest":"` + d + `","reference":"artifact-store://m/` + fmt.Sprint(args["artifact"]) + `/blobs/` + d + `"}`)
		} else {
			step.Result = json.RawMessage(`{"digest":"` + d + `"}`)
		}
	}
	sk, _ := delivery.StepKey(node, id)
	b.steps.mu.Lock()
	b.steps.steps[module+"/"+sk] = step
	b.steps.mu.Unlock()
	return json.RawMessage(`{"step":"` + id + `","key":"` + sk + `","state":"running"}`), nil
}

func (b *buildModules) callsOf(tool string) (out []call) {
	b.mu.Lock()
	defer b.mu.Unlock()
	for _, c := range b.calls {
		if strings.HasSuffix(c.key, "."+tool) {
			out = append(out, c)
		}
	}
	return out
}

type fakeManifests struct {
	byDigest map[string]catalogue.Manifest
}

func (f *fakeManifests) Manifest(_ context.Context, d string) (catalogue.Manifest, error) {
	m, ok := f.byDigest[d]
	if !ok {
		return catalogue.Manifest{}, fmt.Errorf("manifests.%s is not there", d)
	}
	return m, nil
}

func mdigest(c byte) string { return hex64(c) }

type rig struct {
	b     *Builder
	st    *memStore
	bm    *buildModules
	tools *buildrun.ToolchainSet
	mf    *fakeManifests
	key   string
	// asks are the build seats' streams; puller is the node that pulls every ask ("ace" when empty).
	asks   *buildrun.FakeAsks
	puller string
}

// toolPrefix is the start of each build module's tool names, as the fake build modules answer them.
var toolPrefix = map[string]string{buildrun.GoBuildModule: "build_go_", buildrun.NodeBuildModule: "build_node_", ImageBuildModule: "build_image_"}

// answer runs an ask as the build module that pulls it does (buildstep.RunAsk), with the fake build modules' tools on the
// rig's pulling node, and answers the step that node writes.
func (r *rig) answer(a delivery.StepAsk) delivery.Step {
	node := r.puller
	if node == "" {
		node = "ace"
	}
	module, _ := delivery.BuildModuleOf(a.Language)
	runner := buildrun.Runner{Caller: r.bm, Steps: r.bm.steps, Bound: time.Second}
	tool := func(name string) buildstep.StepFunc {
		return func(ctx context.Context, args map[string]any) (any, error) {
			raw, err := runner.Run(ctx, module, node, toolPrefix[module]+name, args)
			if err != nil {
				return nil, err
			}
			return raw, nil
		}
	}
	steps := buildstep.AskSteps{Fetch: tool("fetch"), Build: tool("build"), Copy: tool("copy")}
	out, err := buildstep.RunAsk(context.Background(), steps, a)
	step := delivery.Step{ID: a.ID, Tool: a.Kind + " ask", Node: node, State: delivery.StepPassed}
	if err != nil {
		step.State, step.Reason = delivery.StepFailed, err.Error()
		return step
	}
	step.Result, _ = json.Marshal(out)
	return step
}

func newRig(t *testing.T, artifacts ...catalogue.Artifact) *rig {
	t.Helper()
	r := &rig{st: newMem(), bm: newBuildModules(), tools: &buildrun.ToolchainSet{}, mf: &fakeManifests{byDigest: map[string]catalogue.Manifest{mdigest('a'): {Module: "m", Build: &catalogue.Build{Artifacts: artifacts}}}}}
	for _, n := range []string{"ace", "novox"} {
		r.tools.Put(buildrun.GoBuildModule, n+".go", tcValue(t, "go", "go1.27.1"), false)
		r.tools.Put(buildrun.NodeBuildModule, n+".typescript", tcValue(t, "typescript", "tsc5"), false)
	}
	r.asks = &buildrun.FakeAsks{Answer: r.answer}
	r.b = &Builder{
		Claimer: Claimer{Store: r.st, By: "novox.builder"}, Asks: buildrun.Asker{Publisher: r.asks, Waiter: r.asks, Bound: 2 * time.Second},
		Toolchains: r.tools, Manifests: r.mf, Logf: t.Logf,
		Trunk: func(context.Context, uint64, string) (string, error) { return trunkHead, nil },
	}
	var err error
	if r.key, err = delivery.BuilderBuildKey("m", fp1); err != nil {
		t.Fatal(err)
	}
	return r
}

// agreedToolchains are what the rig's nodes report, and so what a fingerprint computed now names.
var agreedToolchains = map[string]delivery.ToolchainUsed{"go": {Version: "go1.27.1", Recipe: "1"}, "typescript": {Version: "tsc5", Recipe: "1"}}

func moduleValue(t *testing.T, path string) []byte { return moduleValueWith(t, path, agreedToolchains) }

func moduleValueWith(t *testing.T, path string, toolchains map[string]delivery.ToolchainUsed) []byte {
	t.Helper()
	data, err := delivery.EncodeModule(delivery.Module{Repository: "novox/mesh-catalog", Commit: "7a74cee83f88e6585a5511c3cc53bdf0f5303d20", FP: "src1:" + hex64('f'), FP2: fp1, Manifest: mdigest('a'), Path: path, Toolchains: toolchains})
	if err != nil {
		t.Fatal(err)
	}
	return data
}

func (r *rig) consider(t *testing.T, path string) delivery.BuilderBuild {
	t.Helper()
	r.b.Module(context.Background(), "m", moduleValue(t, path))
	r.b.Wait()
	if _, ok := r.st.vals[r.key]; !ok {
		t.Fatal("no build key was written")
	}
	return valueOf(t, r.st, r.key)
}

var (
	goBundle  = catalogue.Artifact{Name: "tool", Kind: "bundle", Language: "go"}
	tsBundle  = catalogue.Artifact{Name: "web", Kind: "bundle", Language: "typescript"}
	archiveA  = catalogue.Artifact{Name: "files", Kind: "archive"}
	imageArt  = catalogue.Artifact{Name: "img", Kind: "image"}
	manifestD = mdigest('a')
)

func TestABundleAndAnArchiveAreBuiltOnOneNodeAndDone(t *testing.T) { // 1607/AC7, ADR 0478 clauses 1, 4
	r := newRig(t, goBundle, archiveA, tsBundle)
	v := r.consider(t, "modules/m")
	if v.State != delivery.BuildDone || v.By != "novox.builder" || v.Manifest != manifestD || len(v.Artifacts) != 3 {
		t.Fatalf("build = %+v, want done by novox.builder with three artifacts", v)
	}
	for i, want := range []string{"files", "tool", "web"} {
		if a := v.Artifacts[i]; a.Name != want || a.Digest != digest || a.Reference != "artifact-store://m/"+want+"/blobs/"+digest {
			t.Errorf("artifact %d = %+v, want %s with the digest and its artifact-store reference (ADR 0498 clause 1)", i, a, want)
		}
	}
	if v.Artifacts[0].Kind != "archive" || v.Artifacts[1].Kind != "bundle" {
		t.Errorf("kinds = %+v", v.Artifacts)
	}
	if got := v.Toolchains["go"]; got.Version != "go1.27.1" || got.Recipe != "1" {
		t.Errorf("toolchains = %+v, want go and typescript named", v.Toolchains)
	}
	if got := v.Toolchains["typescript"]; got.Version != "tsc5" {
		t.Errorf("toolchains = %+v", v.Toolchains)
	}
	// One fetch per build module, on one node (ADR 0478 clause 4); every build names the module's directory.
	if n := len(r.bm.callsOf("build_go_fetch")); n != 1 {
		t.Errorf("%d go fetches, want one", n)
	}
	if n := len(r.bm.callsOf("build_go_build")); n != 2 { // tool and files
		t.Errorf("%d go builds, want 2", n)
	}
	if n := len(r.bm.callsOf("build_node_build")); n != 1 {
		t.Errorf("%d node builds, want 1", n)
	}
	c := r.bm.callsOf("build_go_build")[0]
	if args := c.body.(map[string]any); args["module"] != "modules/m" || !strings.HasPrefix(fmt.Sprint(args["workspace"]), "w-") {
		t.Errorf("build args = %+v, want the module's path and the fetch's workspace", args)
	}
	f := r.bm.callsOf("build_go_fetch")[0].body.(map[string]any)
	if f["repository"] != "novox/mesh-catalog" || f["commit"] != "7a74cee83f88e6585a5511c3cc53bdf0f5303d20" {
		t.Errorf("fetch args = %+v", f)
	}
}

// 1887/AC1, AC2: a trunk fingerprint with no key is one ask on the Go seat's delivery stream, named in the building key
// before it is put, and the builder calls no node; the step a node wrote for it makes the key done naming its reference.
func TestATrunkFingerprintIsOneAskOnTheDeliveryStream(t *testing.T) {
	r := newRig(t, goBundle)
	r.asks.Answer = nil // no node has pulled it yet
	r.b.Module(context.Background(), "m", moduleValue(t, "modules/m"))
	var asks []delivery.StepAsk
	for deadline := time.Now().Add(2 * time.Second); len(asks) == 0; time.Sleep(time.Millisecond) {
		if time.Now().After(deadline) {
			t.Fatal("no ask was put")
		}
		asks = r.asks.Asks()
	}
	a := asks[0]
	if len(asks) != 1 || a.Kind != delivery.AskDelivery || a.Language != delivery.AskGo || a.Build == nil || a.Build.FP != fp1 {
		t.Fatalf("asks = %+v, want one Go delivery ask of the fingerprint", asks)
	}
	if v := valueOf(t, r.st, r.key); v.State != delivery.BuildBuilding || v.Asks[delivery.AskGo] != a.ID {
		t.Fatalf("the key = %+v, want building naming the ask %s", v, a.ID)
	}
	if n := len(r.bm.callsOf("build_go_build")) + len(r.bm.callsOf("build_go_fetch")); n != 0 {
		t.Fatalf("the builder called a node %d times", n)
	}
	r.asks.End(r.answer(a)) // a node pulled it and ran it
	r.b.Wait()
	if v := valueOf(t, r.st, r.key); v.State != delivery.BuildDone || !strings.Contains(v.Step, "on ace") || v.Artifacts[0].Reference == "" || len(v.Asks) != 0 {
		t.Fatalf("the key = %+v, want done on ace naming the reference", v)
	}
}

// 1887/AC3: a builder that starts again while its ask waits puts no second ask: it waits for the step of the ask the
// building key names.
func TestARestartedBuilderWaitsForTheAskTheKeyNames(t *testing.T) {
	r := newRig(t, goBundle)
	const id = "mvl0frv18d1957"
	data, _ := delivery.EncodeBuilderBuild(delivery.BuilderBuild{State: delivery.BuildBuilding, By: "novox.builder", Manifest: manifestD,
		Step: "asked mesh-build-go", Asks: map[string]string{delivery.AskGo: id}})
	r.st.vals[r.key] = data
	r.asks.Answer = nil
	r.asks.End(delivery.Step{ID: id, Node: "shanks", State: delivery.StepPassed,
		Result: []byte(`{"artifacts":[{"artifact":"tool","digest":"` + digest + `","reference":"artifact-store://m/tool/blobs/` + digest + `"}]}`)})
	v := r.consider(t, "modules/m")
	if n := len(r.asks.Asks()); n != 0 {
		t.Fatalf("%d asks put again", n)
	}
	if v.State != delivery.BuildDone || !strings.Contains(v.Step, "on shanks") {
		t.Fatalf("the key = %+v, want done from the ask's step on shanks", v)
	}
}

func TestAFailingStepFailsTheBuildWithItsReasonAndNodeAndIsTriedAgainAsANewRevision(t *testing.T) { // 1607/AC7, ADR 0429 clause 18
	r := newRig(t, goBundle)
	r.bm.fails["ace/build_go_build"] = "go build of tool: undefined: x"
	v := r.consider(t, "modules/m")
	if v.State != delivery.BuildFailed || !strings.Contains(v.Error, "ace") || !strings.Contains(v.Error, "undefined: x") {
		t.Fatalf("build = %+v, want failed with the node and the reason", v)
	}
	rev := r.st.revs[r.key]
	delete(r.bm.fails, "ace/build_go_build")
	v = r.consider(t, "modules/m")
	if v.State != delivery.BuildDone || r.st.revs[r.key] <= rev {
		t.Errorf("build = %+v at revision %d (was %d), want done as a new revision of the same key", v, r.st.revs[r.key], rev)
	}
}

func TestAnImageGoesToOneNodeAndGetsOneDoneKeyWithItsReference(t *testing.T) { // 1705a, ADR 0487 clause 5
	r := newRig(t, imageArt)
	r.puller = "ace" // two nodes qualify; an image still builds on one
	v := r.consider(t, "modules/m")
	if v.State != delivery.BuildDone || len(v.Artifacts) != 1 || v.Artifacts[0].Kind != "image" || v.Artifacts[0].Digest != digest {
		t.Fatalf("build = %+v, want done with one image artifact and its digest", v)
	}
	if v.Artifacts[0].Reference == "" {
		t.Errorf("a trunk image has no reference: %+v", v.Artifacts[0])
	}
	if n := len(r.bm.callsOf("build_image_fetch")); n != 1 {
		t.Errorf("%d image fetches, want one", n)
	}
	writes := r.st.writes
	r.consider(t, "modules/m")
	if r.st.writes != writes || len(r.bm.callsOf("build_image_build")) != 1 {
		t.Errorf("a done image key was built again")
	}
}

func TestABundleAndAnImageOfOneModuleBuildOnOneNodeEach(t *testing.T) { // 1705a
	r := newRig(t, goBundle, imageArt)
	r.puller = "ace"
	v := r.consider(t, "modules/m")
	if v.State != delivery.BuildDone || len(v.Artifacts) != 2 {
		t.Fatalf("build = %+v", v)
	}
	if n := len(r.bm.callsOf("build_go_build")); n != 1 {
		t.Errorf("%d go builds, want 1 (one node per fingerprint, ADR 0478 clause 4)", n)
	}
	if n := len(r.bm.callsOf("build_image_build")); n != 1 {
		t.Errorf("%d image builds, want 1", n)
	}
}

func TestACandidatesImageCallCarriesNoPublishAndItsKeyNoReference(t *testing.T) { // 1705b, lead's decision
	r := newRig(t, imageArt)
	r.puller = "ace"
	trunkModule(t, r)
	r.b.Candidate(context.Background(), "feat%2Fx", candidateValue(t, "feat/x", 7, headX))
	r.b.Wait()
	v := valueOf(t, r.st, r.key)
	if v.State != delivery.BuildDone || len(v.Artifacts) != 1 || v.Artifacts[0].Reference != "" {
		t.Fatalf("build = %+v, want done with no reference", v)
	}
	calls := r.bm.callsOf("build_image_build")
	if len(calls) != 1 {
		t.Fatalf("%d image builds, want 1", len(calls))
	}
	if _, has := calls[0].body.(map[string]any)["publish"]; has {
		t.Errorf("a candidate's image call carries publish: %+v", calls[0].body)
	}
}

func TestATrunkImageCallCarriesPublish(t *testing.T) { // 1705b
	r := newRig(t, imageArt)
	r.puller = "ace"
	r.consider(t, "modules/m")
	calls := r.bm.callsOf("build_image_build")
	if len(calls) != 1 || calls[0].body.(map[string]any)["publish"] != true {
		t.Errorf("calls = %+v, want publish true", calls)
	}
}

func TestAnUnpinnedUpstreamFailsNotPinnedAndIsNeverBuiltAgain(t *testing.T) { // B3, ADR 0498 clause 4
	r := newRig(t, archiveA, catalogue.Artifact{Name: "up", Kind: "upstream", From: "nats:2.11.17-alpine"})
	v := r.consider(t, "modules/m")
	if v.State != delivery.BuildFailed || !strings.HasPrefix(v.Error, delivery.NotPinned) || !strings.Contains(v.Error, "up") {
		t.Fatalf("build = %+v, want failed 'not pinned:' naming the artifact", v)
	}
	if len(r.bm.calls) != 0 {
		t.Errorf("%d calls, want none for an unpinned upstream", len(r.bm.calls))
	}
	writes := r.st.writes
	r.consider(t, "modules/m")
	if r.st.writes != writes {
		t.Errorf("an unpinned upstream's key was written again (%d writes, was %d)", r.st.writes, writes)
	}
}

func TestAModuleKeyWithNoPathFailsNamingThatReason(t *testing.T) { // 1607/AC8, ADR 0478 clause 8
	r := newRig(t, goBundle)
	v := r.consider(t, "")
	if v.State != delivery.BuildFailed || !strings.Contains(v.Error, "path") || len(r.bm.calls) != 0 {
		t.Errorf("build = %+v with %d calls, want failed naming the missing path and nothing called", v, len(r.bm.calls))
	}
}

func TestAnUnreadableManifestFailsTheBuild(t *testing.T) {
	r := newRig(t, goBundle)
	delete(r.mf.byDigest, mdigest('a'))
	v := r.consider(t, "modules/m")
	if v.State != delivery.BuildFailed || !strings.Contains(v.Error, "manifest") {
		t.Errorf("build = %+v, want failed naming the manifest", v)
	}
}

func TestAModuleWithNoFingerprintIsNotBuilt(t *testing.T) { // 1607/AC2
	r := newRig(t)
	data, _ := delivery.EncodeModule(delivery.Module{Repository: "novox/r", Commit: "c", FP: "src1:" + hex64('f'), None2: "toolchain not yet reported"})
	r.b.Module(context.Background(), "n", data)
	r.b.Wait()
	if len(r.st.vals) != 0 {
		t.Errorf("keys %v were written: a module with no new-form fingerprint has nothing to build", r.st.vals)
	}
}

func TestAModuleWithNoArtifactGetsADoneKeyWithNoArtifactAndNoBuildCall(t *testing.T) { // issue 1613, ADR 0478 clause 1
	for name, manifest := range map[string]catalogue.Manifest{"no build": {Module: "m"}, "no artifact": {Module: "m", Build: &catalogue.Build{}}} {
		r := newRig(t)
		r.mf.byDigest[mdigest('a')] = manifest
		v := r.consider(t, "") // a module with nothing to build needs no directory
		if v.State != delivery.BuildDone || len(v.Artifacts) != 0 || v.Manifest != manifestD || v.By != "novox.builder" {
			t.Errorf("%s: build = %+v, want done with no artifact", name, v)
		}
		if len(r.bm.calls) != 0 {
			t.Errorf("%s: %d build module calls, want none", name, len(r.bm.calls))
		}
		writes := r.st.writes
		r.b.tried = map[string]bool{}
		r.consider(t, "")
		if r.st.writes != writes {
			t.Errorf("%s: the done key was written again", name)
		}
	}
}

func TestAKeyTheBuilderLeftBuildingIsBuiltAtStartAndDoneKeysAreNotBuiltTwice(t *testing.T) { // 1607/AC3, AC7
	r := newRig(t, goBundle)
	seed(t, r.st, delivery.BuilderBuild{State: delivery.BuildBuilding, By: "novox.builder", Manifest: manifestD})
	if v := r.consider(t, "modules/m"); v.State != delivery.BuildDone {
		t.Fatalf("build = %+v, want the builder's own building key built", v)
	}
	calls := len(r.bm.calls)
	r.b.Module(context.Background(), "m", moduleValue(t, "modules/m"))
	r.b.Reconsider(context.Background())
	r.b.Wait()
	if len(r.bm.calls) != calls {
		t.Errorf("a done key was built again (%d calls, was %d)", len(r.bm.calls), calls)
	}
}

// Two instances that start together on one key: the second finds the key building and takes it over (ADR 0478 clause 6:
// a key found building at start is taken over, whoever holds it), so both may build; the key is written once, by the one
// whose compare-and-set comes first, and the other's write is refused, never overwriting it.
func TestTwoInstancesStartingTogetherEndWithOneDoneKey(t *testing.T) { // 1607/AC7, review round 4
	r := newRig(t, goBundle)
	other := &Builder{Claimer: Claimer{Store: r.st, By: "ace.builder"}, Asks: r.b.Asks, Toolchains: r.tools, Manifests: r.mf, Logf: t.Logf}
	value := moduleValue(t, "modules/m")
	var wg sync.WaitGroup
	for _, b := range []*Builder{r.b, other} {
		wg.Add(1)
		go func() { defer wg.Done(); b.Module(context.Background(), "m", value); b.Wait() }()
	}
	wg.Wait()
	if v := valueOf(t, r.st, r.key); v.State != delivery.BuildDone || len(v.Artifacts) != 1 {
		t.Errorf("build = %+v, want one done key", v)
	}
	if n := len(r.bm.callsOf("build_go_build")); n < 1 {
		t.Errorf("%d builds, want one for each instance that built", n)
	}
}

func TestAModulesValueThatArrivesWhileItsKeyIsBeingBuiltIsLookedAtAgainWhenItEnds(t *testing.T) { // 1607/AC6 (no event is dropped, no timer)
	r := newRig(t, goBundle)
	r.bm.fails["ace/build_go_build"] = "go build of tool: boom"
	r.bm.hold, r.bm.entered = make(chan struct{}), make(chan struct{}, 8)
	value := moduleValue(t, "modules/m")
	r.b.Module(context.Background(), "m", value)
	<-r.bm.entered // the first build is under way
	r.b.Module(context.Background(), "m", value)
	r.b.Reconsider(context.Background())
	delete(r.bm.fails, "ace/build_go_build") // what the event is about: the build can succeed now
	close(r.bm.hold)
	r.b.Wait()
	if v := valueOf(t, r.st, r.key); v.State != delivery.BuildDone {
		t.Errorf("build = %+v, want the failed key built again as a new revision after the first build ended", v)
	}
}

func TestAKeyIsBuiltOnlyWithTheToolchainItsFingerprintNamesAndNothingIsWrittenOtherwise(t *testing.T) { // 1615/AC4
	r := newRig(t, goBundle)
	old := map[string]delivery.ToolchainUsed{"go": {Version: "go1.26.0", Recipe: "1"}}
	r.b.Module(context.Background(), "m", moduleValueWith(t, "modules/m", old))
	r.b.Wait()
	if len(r.st.vals) != 0 || len(r.bm.calls) != 0 {
		t.Errorf("keys %v and %d calls for a fingerprint of go1.26.0 while the nodes agree on go1.27.1, want neither", r.st.vals, len(r.bm.calls))
	}
	// A recipe that differs is a different toolchain too, and a value that names none (written before) is not built.
	r.b.Module(context.Background(), "m", moduleValueWith(t, "modules/m", map[string]delivery.ToolchainUsed{"go": {Version: "go1.27.1", Recipe: "0"}}))
	r.b.Module(context.Background(), "m", moduleValueWith(t, "modules/m", nil))
	r.b.Wait()
	if len(r.st.vals) != 0 || len(r.bm.calls) != 0 {
		t.Errorf("keys %v and %d calls for a recipe that differs or a value that names no toolchain", r.st.vals, len(r.bm.calls))
	}
	// The toolchain moves under a key that is not built yet: the old fingerprint stays unbuilt, the new one builds.
	r.tools.Put(buildrun.GoBuildModule, "ace.go", tcValue(t, "go", "go1.27.2"), false)
	r.tools.Put(buildrun.GoBuildModule, "novox.go", tcValue(t, "go", "go1.27.2"), false)
	r.b.Reconsider(context.Background())
	r.b.Wait()
	if len(r.st.vals) != 0 {
		t.Errorf("keys %v: the old fingerprint was built with the new toolchain", r.st.vals)
	}
	r.b.Module(context.Background(), "m", moduleValueWith(t, "modules/m", map[string]delivery.ToolchainUsed{"go": {Version: "go1.27.2", Recipe: "1"}}))
	r.b.Wait()
	if v := valueOf(t, r.st, r.key); v.State != delivery.BuildDone || v.Toolchains["go"].Version != "go1.27.2" {
		t.Errorf("build = %+v, want done with go1.27.2", v)
	}
}

func TestNodesTheyDisagreeOnLeaveTheKeyUnwritten(t *testing.T) { // 1615/AC4
	r := newRig(t, goBundle)
	r.tools.Put(buildrun.GoBuildModule, "ace.go", tcValue(t, "go", "go1.26.0"), false)
	r.b.Module(context.Background(), "m", moduleValue(t, "modules/m"))
	r.b.Wait()
	if len(r.st.vals) != 0 || len(r.bm.calls) != 0 {
		t.Errorf("keys %v and %d calls while the nodes disagree", r.st.vals, len(r.bm.calls))
	}
}

func TestARootModulesPathIsDotAndIsGivenToTheBuildTools(t *testing.T) { // 1615/AC4
	r := newRig(t, goBundle)
	if v := r.consider(t, delivery.RootPath); v.State != delivery.BuildDone {
		t.Fatalf("build = %+v, want done for a root module", v)
	}
	if args := r.bm.callsOf("build_go_build")[0].body.(map[string]any); args["module"] != "." {
		t.Errorf("build args = %+v, want module \".\"", args)
	}
}

func TestACandidatesImageIsPublishedOnceWhenTheTrunkNamesItsFingerprint(t *testing.T) { // review r1, mesh-delivery 1; ADR 0487 clause 5
	r := newRig(t, imageArt)
	r.puller = "ace"
	trunkModule(t, r) // the trunk carries another fingerprint; fp1 is the candidate's
	r.b.Candidate(context.Background(), "feat%2Fx", candidateValue(t, "feat/x", 7, headX))
	r.b.Wait()
	v := valueOf(t, r.st, r.key)
	if v.State != delivery.BuildDone || v.Artifacts[0].Reference != "" {
		t.Fatalf("candidate build = %+v, want done with no reference", v)
	}
	if n := len(r.bm.callsOf("build_image_build")); n != 1 {
		t.Fatalf("%d image builds after the candidate, want 1", n)
	}
	// The pull request is merged: the trunk's record names the candidate's fingerprint.
	r.b.Module(context.Background(), "m", moduleValue(t, "modules/m"))
	r.b.Wait()
	v = valueOf(t, r.st, r.key)
	if v.State != delivery.BuildDone || len(v.Artifacts) != 1 || v.Artifacts[0].Reference == "" {
		t.Fatalf("trunk build = %+v, want done with a reference", v)
	}
	calls := r.bm.callsOf("build_image_build")
	published := 0
	for _, c := range calls {
		if c.body.(map[string]any)["publish"] == true {
			published++
		}
	}
	if len(calls) != 2 || published != 1 {
		t.Errorf("%d image builds, %d with publish, want 2 and exactly 1", len(calls), published)
	}
	// Written once more only: looking again builds nothing.
	rev := r.st.revs[r.key]
	r.b.Module(context.Background(), "m", moduleValue(t, "modules/m"))
	r.b.Wait()
	if r.st.revs[r.key] != rev || len(r.bm.callsOf("build_image_build")) != 2 {
		t.Error("a published key was built again")
	}
}

func TestAFailedPublishOfACandidatesImageIsWrittenToTheKey(t *testing.T) { // review r2, mesh-delivery 1; ADR 0487 clause 5
	r := newRig(t, imageArt)
	r.puller = "ace"
	trunkModule(t, r)
	r.b.Candidate(context.Background(), "feat%2Fx", candidateValue(t, "feat/x", 7, headX))
	r.b.Wait()
	if v := valueOf(t, r.st, r.key); v.State != delivery.BuildDone {
		t.Fatalf("candidate build = %+v", v)
	}
	r.bm.fails["ace/build_image_build"] = "push to the registry: connection refused"
	r.b.Module(context.Background(), "m", moduleValue(t, "modules/m")) // the merge: the trunk names the fingerprint
	r.b.Wait()
	v := valueOf(t, r.st, r.key)
	if v.State != delivery.BuildFailed || !strings.Contains(v.Error, "connection refused") || !strings.Contains(v.Error, "publish") {
		t.Fatalf("build = %+v, want failed naming the publish and its reason", v)
	}
	// The failed key is retaken as any failed key is, and ends published once the registry answers.
	delete(r.bm.fails, "ace/build_image_build")
	r.b.Module(context.Background(), "m", moduleValue(t, "modules/m"))
	r.b.Wait()
	if v := valueOf(t, r.st, r.key); v.State != delivery.BuildDone || v.Artifacts[0].Reference == "" {
		t.Errorf("build = %+v, want done with a reference", v)
	}
}

// goneAsks answers Gone from a function of the ask, and counts how often it was asked; it keeps the ids it was asked to
// drop from their stream (Dropper).
type goneAsks struct {
	mu      sync.Mutex
	n       int
	why     func(a delivery.StepAsk) string
	dropped []string
}

func (g *goneAsks) Drop(_ context.Context, a delivery.StepAsk) error {
	g.mu.Lock()
	defer g.mu.Unlock()
	g.dropped = append(g.dropped, a.ID)
	return nil
}

func (g *goneAsks) Gone(_ context.Context, a delivery.StepAsk) (string, error) {
	g.mu.Lock()
	g.n++
	g.mu.Unlock()
	return g.why(a), nil
}

func (g *goneAsks) asked() int {
	g.mu.Lock()
	defer g.mu.Unlock()
	return g.n
}

// waitForAsks waits until n asks were put.
func waitForAsks(t *testing.T, r *rig, n int) []delivery.StepAsk {
	t.Helper()
	for deadline := time.Now().Add(2 * time.Second); len(r.asks.Asks()) < n; time.Sleep(time.Millisecond) {
		if time.Now().After(deadline) {
			t.Fatalf("%d asks put, want %d", len(r.asks.Asks()), n)
		}
	}
	return r.asks.Asks()
}

// Review round 2 item 1: a build ask that waits in its stream longer than the step bound is not failed and not asked
// again; the key is done when a node takes it. Issue 1945: an ask that can no longer be answered (its stream gave it up)
// is asked again under a new id, said, at most Askings times; a person asks it again by hand the same way.
func TestABuildAskWaitingInItsStreamIsNotBounded(t *testing.T) {
	t.Run("waits in its stream: never asked again", func(t *testing.T) {
		r := newRig(t, goBundle)
		r.asks.Answer = nil
		r.b.Asks = buildrun.Asker{Publisher: r.asks, Waiter: r.asks, Bound: 20 * time.Millisecond}
		gone := &goneAsks{why: func(delivery.StepAsk) string { return "" }}
		r.b.Gone, r.b.CheckAfter = gone, 5*time.Millisecond
		r.b.Module(context.Background(), "m", moduleValue(t, "modules/m"))
		waitForAsks(t, r, 1)
		time.Sleep(100 * time.Millisecond)
		if v := valueOf(t, r.st, r.key); v.State != delivery.BuildBuilding {
			t.Fatalf("the key = %+v while its ask waits, want building", v)
		}
		if gone.asked() == 0 {
			t.Fatal("whether the ask can still be answered was never read at the check bound") // 1945
		}
		r.asks.End(r.answer(r.asks.Asks()[0]))
		r.b.Wait()
		if v := valueOf(t, r.st, r.key); v.State != delivery.BuildDone || len(r.asks.Asks()) != 1 {
			t.Fatalf("the key = %+v after %d asks, want done from the one ask", v, len(r.asks.Asks()))
		}
	})
	for _, c := range []struct {
		name    string
		askings int
		// step is the key's step words at start when it names an ask (a key taken over), "" for a fresh build.
		step   string
		byHand bool
		always bool // Gone says every ask cannot be answered, not only the first
		dead   bool // DEAD_LETTERS keeps the first ask: the seat gave it up (issue 734)
		puts   int
		done   bool
		asking int // the asking the event says, 0 when none is said
	}{
		{name: "given up by its stream: asked again under a new id and done from it", puts: 2, done: true, asking: 2},
		{name: "asked again by hand: the same, with no check bound", byHand: true, puts: 2, done: true, asking: 2},
		{name: "given up into DEAD_LETTERS: its wait ends failed with the words and it is asked again at once", dead: true, puts: 2, done: true, asking: 2},
		{name: "never answerable: failed after its askings", askings: 2, always: true, puts: 2},
		{name: "taken over at its last asking: failed, not asked again", askings: 3, always: true, step: "asked mesh-build-go again (asking 3): x", puts: 0},
	} {
		t.Run(c.name, func(t *testing.T) { // 1945
			r := newRig(t, goBundle)
			r.asks.Answer = nil
			r.b.Askings = c.askings
			var said []AskedAgain
			var mu sync.Mutex
			r.b.Said = func(e AskedAgain) { mu.Lock(); said = append(said, e); mu.Unlock() }
			first := ""
			if c.step != "" {
				first = "mvl0frv18d1960"
				data, _ := delivery.EncodeBuilderBuild(delivery.BuilderBuild{State: delivery.BuildBuilding, By: "novox.builder", Manifest: manifestD,
					Step: c.step, Asks: map[string]string{delivery.AskGo: first}})
				r.st.vals[r.key] = data
			}
			gone := &goneAsks{}
			dead := &buildrun.DeadLetters{}
			if c.dead {
				r.b.Asks = buildrun.Asker{Publisher: r.asks, Waiter: buildrun.LostAskWaiter{Inner: r.asks, Dead: dead}, Bound: 2 * time.Second}
			}
			if !c.byHand && !c.dead {
				gone.why = func(a delivery.StepAsk) string {
					if c.always || a.ID == first || first == "" {
						return "it waits first in line while a node took a later ask"
					}
					return ""
				}
				r.b.Gone, r.b.CheckAfter = gone, 5*time.Millisecond
			}
			r.b.Module(context.Background(), "m", moduleValue(t, "modules/m"))
			if c.dead {
				dead.Heard(buildrun.GivenUp{AskID: waitForAsks(t, r, 1)[0].ID, Stream: "SEAT_NODE_BUILD_GO", Deliveries: 5,
					At: time.Date(2026, 10, 26, 12, 26, 40, 0, time.UTC)})
			}
			if c.byHand {
				waitForAsks(t, r, 1)
				for deadline := time.Now().Add(2 * time.Second); len(r.b.AskAgain(r.key, "stuck since 19:06")) == 0; time.Sleep(time.Millisecond) {
					if time.Now().After(deadline) {
						t.Fatal("no lane of the key waits")
					}
				}
			}
			if c.done {
				asks := waitForAsks(t, r, c.puts)
				if first == "" && !c.byHand {
					first = asks[0].ID
				}
				last := asks[len(asks)-1]
				if v := valueOf(t, r.st, r.key); v.Asks[delivery.AskGo] != last.ID || !strings.Contains(v.Step, "again (asking 2)") {
					t.Fatalf("the key = %+v, want building naming the ask asked again %s", v, last.ID)
				}
				r.asks.End(r.answer(last))
			}
			r.b.Wait()
			v := valueOf(t, r.st, r.key)
			if n := len(r.asks.Asks()); n != c.puts {
				t.Errorf("%d asks put, want %d", n, c.puts)
			}
			if c.done && v.State != delivery.BuildDone {
				t.Errorf("the key = %+v, want done from the ask asked again", v)
			}
			if !c.done && (v.State != delivery.BuildFailed || !strings.Contains(v.Error, "could not be answered and was asked")) {
				t.Errorf("the key = %+v, want failed saying the ask could not be answered", v)
			}
			mu.Lock()
			defer mu.Unlock()
			// Note 62: the old message of an ask asked again because its stream gave it up is dropped from the stream.
			if gone.mu.Lock(); c.done && !c.byHand && !c.dead && (len(gone.dropped) != 1 || gone.dropped[0] != first) {
				t.Errorf("dropped %v from the stream, want the old ask %s", gone.dropped, first)
			}
			gone.mu.Unlock()
			if c.asking > 0 && (len(said) != 1 || said[0].Asking != c.asking || said[0].New == said[0].Old || said[0].Key != r.key || said[0].Why == "") {
				t.Errorf("said %+v, want once at asking %d", said, c.asking)
			}
			if c.dead && (len(said) != 1 || !strings.Contains(said[0].Why, buildrun.LostWords+" after 5 deliveries at 2026-10-26T12:26:40Z")) {
				t.Errorf("said %+v, want the ask asked again saying the seat gave it up", said)
			}
		})
	}
	t.Run("what the bus says of an ask", func(t *testing.T) { // 1945
		put := time.Date(2026, 10, 25, 17, 6, 0, 0, time.UTC)
		taken := func(kind string, at time.Time) *Taken {
			return &Taken{Ask: "later", Kind: kind, At: at, Node: "g14", Started: at}
		}
		later := taken(delivery.AskDelivery, put.Add(time.Minute))
		// ahead is n messages put before the ask, a minute apart, each with step (its state, "" for none).
		ahead := func(n int, step string) []Queued {
			var qs []Queued
			for i := range n {
				at := put.Add(-time.Duration(n-i) * time.Minute)
				qs = append(qs, Queued{Seq: uint64(i + 1), Ask: fmt.Sprint("a", i), Kind: delivery.AskDelivery, At: at, PutAt: at, Step: step})
			}
			return qs
		}
		seen := func(qs []Queued, last *Taken) AskSeen {
			return AskSeen{Stream: "S", Kind: delivery.AskDelivery, At: put, OnStream: true, PutAt: put, Ahead: qs, Last: last}
		}
		for _, c := range []struct {
			name    string
			seen    AskSeen
			want    string // a part of the why, "" when it can be answered
			waiting int
		}{
			{"a node took it", AskSeen{Stream: "S", Step: true}, "", 0},
			{"no longer on its stream", AskSeen{Stream: "S"}, "no longer holds it", 0},
			{"first in line, a later ask taken", seen(nil, later), "no longer delivers it", 0},
			{"first in line, nothing taken since", seen(nil, nil), "", 0},
			{"first in line, the ask taken last was asked before it", seen(nil, taken(delivery.AskDelivery, put.Add(-time.Second))), "", 0},
			{"two wait ahead, nothing taken since", seen(ahead(2, ""), nil), "", 2},
			{"two ahead passed over, the ask not yet", seen(ahead(2, ""), taken(delivery.AskDelivery, put.Add(-time.Second))), "", 0},
			// Note 62: seven messages SEAT_NODE_BUILD_GO gave up on sat ahead of a Go ask for five hours.
			{"seven given up on ahead, a later ask taken", seen(ahead(7, ""), later), "behind 7 given up on or taken", 0},
			{"seven taken ahead (failed as poison), a later ask taken", seen(ahead(7, delivery.StepFailed), later), "no longer delivers it", 0},
			{"a check ask taken later proves a delivery ask passed", seen(ahead(7, ""), taken(delivery.AskCheck, put.Add(time.Minute))), "no longer delivers it", 0},
			{"a delivery ask taken later does not prove a check ask passed", func() AskSeen { s := seen(ahead(3, ""), later); s.Kind = delivery.AskCheck; return s }(), "", 3},
		} {
			got := c.seen.Why()
			if (c.want == "") != (got == "") || !strings.Contains(got, c.want) || c.seen.Waiting() != c.waiting {
				t.Errorf("%s: why %q and %d waiting, want %q and %d", c.name, got, c.seen.Waiting(), c.want, c.waiting)
			}
		}
		if at := time.UnixMilli(1793120000123); !AskedAt(strconv.FormatInt(at.UnixMilli(), 36)+"0a1b2c").Equal(at) || !AskedAt("x").IsZero() {
			t.Errorf("AskedAt does not read an ask id's time")
		}
	})
	t.Run("the tool builder_stuck", func(t *testing.T) { // 1945
		at := time.Date(2026, 10, 25, 17, 6, 0, 0, time.UTC)
		state := func(vals map[string]string) StateRead {
			return StateRead{Keys: func() ([]string, error) {
				var ks []string
				for k := range vals {
					ks = append(ks, k)
				}
				return ks, nil
			}, Get: func(k string) (json.RawMessage, time.Time, error) {
				if v, ok := vals[k]; ok {
					return json.RawMessage(v), at, nil
				}
				return nil, time.Time{}, nil
			}}
		}
		key, _ := delivery.BuilderBuildKey("m", fp1)
		done, _ := delivery.BuilderBuildKey("d", fp1)
		building, _ := delivery.EncodeBuilderBuild(delivery.BuilderBuild{State: delivery.BuildBuilding, By: "novox.builder", Manifest: manifestD,
			Step: "asked mesh-build-go again (asking 2): x", Asks: map[string]string{delivery.AskGo: "mvo53jcm70b5f7", delivery.AskImage: "mvo53jcm70b5f8"}})
		finished, _ := delivery.EncodeBuilderBuild(delivery.BuilderBuild{State: delivery.BuildDone, Manifest: manifestD, Step: "built"})
		running, _ := json.Marshal(delivery.Step{V: delivery.Version, ID: "mvo53jcm70b5f8", Tool: "delivery ask", Node: "g14", State: delivery.StepRunning, Started: at})
		_, reask, _ := NewReAsk("m", fp1, "stuck", "shanks.lead", at)
		r := StuckReader{Builds: state(map[string]string{key: string(building), done: string(finished)}), ReAsks: state(map[string]string{key: string(reask)}),
			Steps:   map[string]StateRead{buildrun.GoBuildModule: state(map[string]string{}), ImageBuildModule: state(map[string]string{"g14.mvo53jcm70b5f8": string(running)})},
			Hearing: state(map[string]string{buildrun.HearingKey: `{"heard":false,"streams":["SEAT_NODE_BUILD_GO"],"why":"DEAD_LETTERS is not heard: SEAT_NODE_BUILD_GO: permissions violation","at":"2026-10-26T13:00:00Z"}`}),
			Now:     func() time.Time { return at.Add(time.Hour) }}
		out, err := r.Stuck("")
		if err != nil {
			t.Fatal(err)
		}
		// Issue 734, review round 1: a builder that does not hear DEAD_LETTERS says so, with why.
		if dl := out["dead_letters"].(map[string]any); dl["heard"] != false || !strings.Contains(dl["why"].(string), "permissions violation") {
			t.Errorf("dead_letters = %v, want not heard, saying why", dl)
		}
		stuck := out["stuck"].([]Stuck)
		if len(stuck) != 1 || stuck[0].Key != key || stuck[0].Age != "1h0m0s" || stuck[0].NoneStep != 1 || stuck[0].ReAsk == nil || stuck[0].ReAsk.Why != "stuck" {
			t.Fatalf("stuck = %+v, want the building key alone, an hour old, one ask with no step, with its ask again", stuck)
		}
		a := stuck[0].Asks
		if len(a) != 2 || a[0].Language != delivery.AskGo || a[0].Asking != 2 || a[0].Step != "none" || a[0].Asked.IsZero() ||
			a[1].Asking != 1 || !strings.HasPrefix(a[1].Step, "running on g14") {
			t.Fatalf("asks = %+v, want go at asking 2 with no step and image at asking 1 running on g14", a)
		}

		// 1827: on the live shape (3000 build keys over 100 modules, 1 ms a Get, three keys of each module building) a module reads only its
		// own keys, the whole answer reads MaxReads values in parallel and says it was cut, and the history (Written) is asked
		// only for the rows kept.
		var gets, written, inFlight, maxFlight atomic.Int64
		vals := map[string]string{}
		for i := 0; i < 3000; i++ {
			k, _ := delivery.BuilderBuildKey(fmt.Sprintf("mod%02d", i%100), fmt.Sprintf("src2:%064x", i))
			vals[k] = string(finished)
			if (i/100)%10 == 0 {
				vals[k] = string(building)
			}
		}
		slow := state(vals)
		get := slow.Get
		slow.Get = func(k string) (json.RawMessage, time.Time, error) {
			gets.Add(1)
			n := inFlight.Add(1)
			for m := maxFlight.Load(); n > m && !maxFlight.CompareAndSwap(m, n); m = maxFlight.Load() {
			}
			time.Sleep(time.Millisecond)
			inFlight.Add(-1)
			raw, _, err := get(k)
			return raw, time.Time{}, err
		}
		slow.Written = func(string) time.Time { written.Add(1); return at }
		for _, row := range []struct {
			module string
			stuck  int
			gets   int64
			cut    bool
		}{{"mod10", 3, 30, false}, {"", 100, MaxReads, true}} {
			gets.Store(0)
			written.Store(0)
			out, err := StuckReader{Builds: slow, ReAsks: state(map[string]string{}), Steps: map[string]StateRead{}, Now: func() time.Time { return at }}.Stuck(row.module)
			if err != nil {
				t.Fatal(err)
			}
			_, cut := out["cut"]
			if n := len(out["stuck"].([]Stuck)); n != row.stuck || cut != row.cut || written.Load() != int64(n) || gets.Load() != row.gets {
				t.Errorf("%q: %d stuck, %d gets, %d written, cut %v; want %d stuck and gets, written for each, cut %v", row.module, n, gets.Load(), written.Load(), cut, row.stuck, row.cut)
			}
		}
		if maxFlight.Load() < 2 {
			t.Errorf("the values were read one at a time")
		}
	})
}

// heldAsks says an ask is held when its id is among held.
type heldAsks map[string]bool

func (h heldAsks) Held(_ context.Context, a delivery.StepAsk) (bool, error) { return h[a.ID], nil }

// 1910: a builder that stopped between naming the ask in its key and putting it left a key naming an ask neither the
// stream holds nor any node ran: started again, the builder puts that ask, under the same id, once, and the key is
// built from its step; an ask the stream holds is not put again.
func TestAnAskTheKeyNamesAndNobodyPutIsPutAtStart(t *testing.T) {
	for _, held := range []bool{false, true} {
		r := newRig(t, goBundle)
		const id = "mvl0frv18d1958"
		data, _ := delivery.EncodeBuilderBuild(delivery.BuilderBuild{State: delivery.BuildBuilding, By: "novox.builder", Manifest: manifestD,
			Step: "asked mesh-build-go", Asks: map[string]string{delivery.AskGo: id}})
		r.st.vals[r.key] = data
		r.b.Held = heldAsks{id: held}
		if held {
			r.asks.Answer = nil
			r.asks.End(delivery.Step{ID: id, Node: "shanks", State: delivery.StepPassed,
				Result: []byte(`{"artifacts":[{"artifact":"tool","digest":"` + digest + `","reference":"artifact-store://m/tool/blobs/` + digest + `"}]}`)})
		}
		v := r.consider(t, "modules/m")
		asks := r.asks.Asks()
		switch {
		case held && len(asks) != 0:
			t.Errorf("an ask the stream holds was put again: %+v", asks)
		case !held && (len(asks) != 1 || asks[0].ID != id):
			t.Errorf("the ask nobody put: asks %+v, want one under %s", asks, id)
		}
		if v.State != delivery.BuildDone {
			t.Errorf("held %v: the key = %+v, want done", held, v)
		}
	}
}

// unreadableHeld cannot tell whether an ask is held.
type unreadableHeld struct{}

func (unreadableHeld) Held(context.Context, delivery.StepAsk) (bool, error) {
	return false, errors.New("permissions violation for publish to $JS.API.STREAM.INFO.SEAT_NODE_BUILD_GO")
}

// 1910: a take-over that cannot read whether the ask its key names is on its stream says so and waits for the ask's step:
// the key is not failed, and the build finishes when a node ran the ask.
func TestATakeOverThatCannotReadTheStreamWaitsForTheAsk(t *testing.T) {
	r := newRig(t, goBundle)
	const id = "mvl0frv18d1959"
	data, _ := delivery.EncodeBuilderBuild(delivery.BuilderBuild{State: delivery.BuildBuilding, By: "novox.builder", Manifest: manifestD,
		Step: "asked mesh-build-go", Asks: map[string]string{delivery.AskGo: id}})
	r.st.vals[r.key] = data
	r.b.Held = unreadableHeld{}
	r.asks.Answer = nil
	r.asks.End(delivery.Step{ID: id, Node: "shanks", State: delivery.StepPassed,
		Result: []byte(`{"artifacts":[{"artifact":"tool","digest":"` + digest + `","reference":"artifact-store://m/tool/blobs/` + digest + `"}]}`)})
	v := r.consider(t, "modules/m")
	if v.State != delivery.BuildDone || len(r.asks.Asks()) != 0 {
		t.Fatalf("the key = %+v after %d asks, want done from the ask's step, none put", v, len(r.asks.Asks()))
	}
}