Composer: find the store by the holder of any of its names, the old seat's too (ADR 0632 §2; issue 1966)

While the indexer holds distribution's new manifest, every node reads main's,
which claims only mesh-artifact-store: a new engine must find the store there.

Claude-Session: https://claude.ai/code/session_01JG73KJNrH5EgFXMKKYSrig

internal/compose/frombus/frombus.go

@@ -1142,7 +1142,7 @@ func storeSought(in compose.Input) string {
 	for _, n := range in.Nodes {
 		nodes = append(nodes, n.Name)
 		for _, a := range n.Assigned {
-			if m, ok := in.Catalogue[a]; ok && claimsSeat(m, compose.StoreSeat) {
+			if m, ok := in.Catalogue[a]; ok && claimsStore(m) {
 				where = append(where, a+" on "+n.Name)
 			}
 		}
@@ -1157,10 +1157,10 @@ func storeSought(in compose.Input) string {
 		", none of it on the private network with a listen open to the mesh"
 }
 
-// claimsSeat says whether m claims seat at the mesh's scope.
-func claimsSeat(m catalogue.Manifest, seat string) bool {
+// claimsStore says whether m claims a name of the store (resolution.StoreSeats) at the mesh's scope.
+func claimsStore(m catalogue.Manifest) bool {
 	for _, cl := range m.Claims {
-		if cs, ok := catalogue.SeatNamed(cl.Name); ok && cs.Name == seat && cl.At() == catalogue.ScopeMesh {
+		if cs, ok := catalogue.SeatNamed(cl.Name); ok && slices.Contains(resolution.StoreSeats, cs.Name) && cl.At() == catalogue.ScopeMesh {
 			return true
 		}
 	}

internal/compose/rendering.go

@@ -3,6 +3,7 @@ package compose
 import (
 	"errors"
 	"fmt"
+	"slices"
 	"sort"
 	"strings"
 
@@ -332,11 +333,18 @@ func (c *composer) namesInTheMesh() map[string]string {
 const StoreSeat = "container-image-registry"
 
 // storeHolders are the modules holding the store's seat: the holdings on record, and only where none is on record every
-// module of the catalogue claiming it at the mesh's scope, as a seat holder's reach is read (replicatedHolders).
+// module of the catalogue claiming it at the mesh's scope, as a seat holder's reach is read (replicatedHolders). Any name
+// of the store counts (resolution.StoreSeats): until every counted engine states the new reading, the manifest every
+// node reads is the holder's old one, which claims only mesh-artifact-store (ADR 0632 §2), and an engine that finds the
+// store by the seat must find it there too.
 func (c *composer) storeHolders() map[string]catalogue.Manifest {
+	isStore := func(claim string) bool {
+		hs, ok := catalogue.SeatNamed(claim)
+		return ok && slices.Contains(resolution.StoreSeats, hs.Name)
+	}
 	out := map[string]catalogue.Manifest{}
 	for _, h := range c.in.Holdings {
-		if hs, ok := catalogue.SeatNamed(h.Claim); ok && hs.Name == StoreSeat && h.Scope == catalogue.ScopeMesh && h.Module != "" {
+		if isStore(h.Claim) && h.Scope == catalogue.ScopeMesh && h.Module != "" {
 			if m, known := c.in.Catalogue[h.Module]; known {
 				out[h.Module] = m
 			}
@@ -347,7 +355,7 @@ func (c *composer) storeHolders() map[string]catalogue.Manifest {
 	}
 	for name, m := range c.in.Catalogue {
 		for _, cl := range m.Claims {
-			if cs, ok := catalogue.SeatNamed(cl.Name); ok && cs.Name == StoreSeat && cl.At() == catalogue.ScopeMesh {
+			if isStore(cl.Name) && cl.At() == catalogue.ScopeMesh {
 				out[name] = m
 			}
 		}

internal/compose/rendering_test.go

@@ -318,6 +318,36 @@ func TestTheStoreIsFoundByTheImageSeatsHolderAndItsListen(t *testing.T) {
 			t.Errorf("${seat:%s:reach} is %q", seat, r.SeatReach[seat])
 		}
 	}
+	// main's distribution, the manifest every node reads while the indexer holds the new one (ADR 0632 §2): it claims
+	// only mesh-artifact-store and serves the retired provision; the engine finds the store by that claim and its listen.
+	old := in
+	old.Catalogue = map[string]catalogue.Manifest{}
+	for k, v := range in.Catalogue {
+		if k != "registry" {
+			old.Catalogue[k] = v
+		}
+	}
+	old.Catalogue["distribution"] = catalogue.Manifest{Module: "distribution", Version: "2",
+		Provides: []catalogue.Offer{{Name: catalogue.ArtifactStoreProvision, Scope: catalogue.ScopeMesh}},
+		Claims:   []catalogue.Claim{{Name: "mesh-artifact-store", Scope: catalogue.ScopeMesh}},
+		Serves:   map[string]map[string]any{catalogue.ArtifactStoreProvision: {"port": 5000}},
+		Listens:  []catalogue.Listening{{Name: "registry", Port: 5000, Protocol: "tcp", From: catalogue.FromMesh}}}
+	old.Nodes = append([]Node(nil), in.Nodes...)
+	for i := range old.Nodes {
+		if old.Nodes[i].Name == "anchor" {
+			var kept []string
+			for _, a := range old.Nodes[i].Assigned {
+				if a != "registry" && a != "old" {
+					kept = append(kept, a)
+				}
+			}
+			old.Nodes[i].Assigned = append(kept, "distribution")
+			old.Nodes[i].Ports = map[string]map[int]int{"distribution": {5000: 5400}}
+		}
+	}
+	if got := placed(t, old, "laptop").Rendering.ArtifactStore; got != "anchor.internal:5400" {
+		t.Errorf("main's distribution, claiming only mesh-artifact-store, is reached at %q, want anchor.internal:5400", got)
+	}
 	m := in.Catalogue["registry"]
 	m.Listens = append(m.Listens, catalogue.Listening{Name: "other", Port: 5300, From: catalogue.FromMesh})
 	in.Catalogue["registry"] = m