Read an ask's stream at take-over by its name, as the broker grants it, and wait for the ask when that read fails rather than fail a key whose build may still finish (issue 1910)

modules/mesh-delivery-builder/cmd/mesh-delivery-builder/held.go

@@ -41,14 +41,16 @@ func (h heldOnTheBus) Held(ctx context.Context, a delivery.StepAsk) (bool, error
 	if err != nil {
 		return false, err
 	}
-	name, err := h.js.StreamNameBySubject(ctx, subject)
-	if errors.Is(err, jetstream.ErrStreamNotFound) {
-		return false, nil
-	}
+	// The seat's stream by its name (delivery.AskStream), as the broker grants the builder its information and its
+	// messages by sequence and nothing wider (issue 1910).
+	name, err := delivery.AskStream(a.Language)
 	if err != nil {
 		return false, err
 	}
 	stream, err := h.js.Stream(ctx, name)
+	if errors.Is(err, jetstream.ErrStreamNotFound) {
+		return false, nil
+	}
 	if err != nil {
 		return false, err
 	}

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

@@ -677,8 +677,9 @@ func (b *Builder) runLane(ctx context.Context, l *lane, repository string, m del
 		if b.Held != nil {
 			held, err := b.Held.Held(ctx, ask)
 			if err != nil {
-				l.err = fmt.Errorf("whether the ask %s of %s the key names is on its stream cannot be read: %w", ask.ID, l.module, err)
-				return
+				// Said, and the key is not failed: the ask may well be on its stream and its build finish (issue 1910).
+				b.logf("whether the ask %s of %s the key names is on its stream cannot be read, so it is waited for as put: %v", ask.ID, l.module, err)
+				held = true
 			}
 			if !held {
 				// The builder that named it stopped before it put it (issue 1910): put it now, under the same id.

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

@@ -3,6 +3,7 @@ package build
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"git.novox.be/novox/mesh-sdk/go/delivery/buildrun"
 	"strings"
@@ -671,3 +672,28 @@ func TestAnAskTheKeyNamesAndNobodyPutIsPutAtStart(t *testing.T) {
 		}
 	}
 }
+
+// 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()))
+	}
+}