issue 974: the checks are queued by pull request on two work-queue streams, taken after a delivery build, dropped when judged, stopped when their key moves; the reordering and the forge-asking end are gone

cmd/mesh-controller/checks.go

@@ -191,8 +191,9 @@ func (f following) PullUpdated(ctx context.Context, p link.PullUpdated) error {
 	if err := ask.Ask(ctx, request); err != nil {
 		return err
 	}
-	// A new head ends the check of the old one (novox/hq issue 726).
-	endingSupersededChecks(ctx, seat, p, request.ID, f.oneShot)
+	// **A newer request replaces the one still waiting, and a newer key stops the one running** (novox/hq ADR 0406 §3, §4,
+	// issue 974): the check queue keeps one request a pull request, and a running check watches its key. Nothing is asked
+	// of the forge here (issue 726).
 	what := "its own merge-check.sh alone: " + noModuleTouched
 	if scope.gated() {
 		what = fmt.Sprintf("the gate over %s (a merge would build %d module(s) in %d tier(s))",
@@ -270,7 +271,7 @@ func checkRequestFor(ctx context.Context, open *stores, p link.PullUpdated, scop
 		Held:       heldBy(ctx),
 		Seats:      seatBases(ctx),
 		Source:     sourceOnSeat(source),
-		Check: &link.CheckRequest{Owner: p.Owner, Repo: p.Repo, Number: p.Number, Base: p.Base,
+		Check: &link.CheckRequest{Owner: p.Owner, Repo: p.Repo, Number: p.Number, Base: p.Base, Trunk: p.BaseSHA, Ready: p.Ready,
 			Paths: p.Paths, Beside: beside, Modules: scope.Modules, Dependents: scope.Dependents, New: scope.New,
 			Manifests: scope.Manifests, Judge: scope.Judge, Builds: builds, Named: namedForTheCheck(ctx, p, builds),
 			Release: release, Running: runningBy(ctx)},