issue 1840/S3: keep each node's declared packages on the bus, so the pacman verbs can say what a node declares

internal/broker/controller_buckets.go

@@ -104,6 +104,9 @@ var (
 	AssignmentsBucket    = BucketName(ControllerSeat, MirrorAssignments)
 	DeclaredConfigBucket = BucketName(ControllerSeat, MirrorDeclaredConfig)
 	PredefinedBucket     = BucketName(ControllerSeat, MirrorPredefined)
+	// DeclaredPackagesBucket holds, keyed by the node, each package the modules assigned to it declare, present or absent,
+	// with the declaring modules: what the pacman module's verbs read to say a package is declared (ADR 0507 §5).
+	DeclaredPackagesBucket = BucketName(ControllerSeat, MirrorDeclaredPackages)
 )
 
 // The mirrors' local names, as a reader names them in `reads` after `mesh-controller.`.
@@ -111,6 +114,8 @@ const (
 	MirrorAssignments    = "assignments"
 	MirrorDeclaredConfig = "declared-config"
 	MirrorPredefined     = "predefined"
+	// MirrorDeclaredPackages is the local name of the packages each node's modules declare (ADR 0507 §5, issue 1840/S3).
+	MirrorDeclaredPackages = "declared-packages"
 )
 
 // The chain's buckets (novox/hq ADR 0408, issue 1089): builds, rollouts and assignments are one chain kept on the bus
@@ -153,7 +158,7 @@ func ChainBuckets() []string { return []string{BuildsBucket, RolloutsBucket, Ass
 // ControllerMirrors are the local names of the controller's buckets a module may read: the record mirrors and the
 // chain's buckets.
 func ControllerMirrors() []string {
-	return []string{MirrorAssignments, MirrorDeclaredConfig, MirrorPredefined, ChainBuilds, ChainRollouts, ChecksRunning, PlansBuilding}
+	return []string{MirrorAssignments, MirrorDeclaredConfig, MirrorPredefined, ChainBuilds, ChainRollouts, ChecksRunning, PlansBuilding, MirrorDeclaredPackages}
 }
 
 // MirrorsWrittenByAnother are the controller's mirrors whose writer is not the controller, each with its reason: the rule
@@ -222,6 +227,7 @@ func IsControllerBucket(bucket string) bool {
 	return bucket == CallsBucket || bucket == HandActsBucket || bucket == ConditionsBucket ||
 		bucket == ConditionHistoryBucket || bucket == LeaseBucket || bucket == AskedBucket ||
 		bucket == AssignmentsBucket || bucket == DeclaredConfigBucket || bucket == PredefinedBucket ||
+		bucket == DeclaredPackagesBucket ||
 		bucket == MergeWindowBucket || bucket == RolloutSilentBucket || bucket == CheckRunningBucket ||
 		bucket == DeliveryMergesBucket || bucket == BuildsBucket || bucket == RolloutsBucket ||
 		bucket == PlansBuildingBucket || bucket == delivery.HaveBucket
@@ -230,7 +236,7 @@ func IsControllerBucket(bucket string) bool {
 // ControllerBuckets are the controller's own buckets, in the order they are asserted.
 func ControllerBuckets() []string {
 	return []string{LeaseBucket, CallsBucket, HandActsBucket, ConditionsBucket, ConditionHistoryBucket, AskedBucket,
-		AssignmentsBucket, DeclaredConfigBucket, PredefinedBucket, MergeWindowBucket, RolloutSilentBucket, CheckRunningBucket,
+		AssignmentsBucket, DeclaredConfigBucket, PredefinedBucket, DeclaredPackagesBucket, MergeWindowBucket, RolloutSilentBucket, CheckRunningBucket,
 		DeliveryMergesBucket, PlansBuildingBucket, BuildsBucket, RolloutsBucket, delivery.HaveBucket}
 }
 
@@ -446,6 +452,9 @@ func (j *JetStream) EnsureControllerBuckets() error {
 		{PredefinedBucket, "the list of predefined keys the mesh published, the newest trunk build's of the " +
 			"catalogue, one key `list` (novox/hq ADR 0348 §7, design 57 K3): written by the controller alone from " +
 			"its store when a newer list is kept, read through `reads`"},
+		{DeclaredPackagesBucket, "each package the modules assigned to a node declare, present or absent, with the " +
+			"declaring modules, keyed by the node (novox/hq ADR 0507 §5): written by the controller alone when it " +
+			"composes the node, only on a change, read through `reads`"},
 	} {
 		if _, err := js.CreateOrUpdateKeyValue(ctx, jetstream.KeyValueConfig{
 			Bucket:         m.bucket,