A build records the bases it was handed, and the mesh reads its edges from builds

Bases reach a recipe as build arguments, so the digest was never in the file the builder read
edges from: no build on the mesh recorded what it stood on, and 'build --on', the bases-first
order and the merge follow-up all walked a graph with no edges (novox/hq 04-ISSUES/131). The
builder now reports every base it resolved; the controller records them by artifact path and
reads the newest build's edges from the store, since a recorded manifest carries no build.on.

cmd/mesh-controller/upgrades.go

@@ -250,7 +250,11 @@ func (f following) SourceMoved(ctx context.Context, m link.SourceMoved) error {
 			m.Owner, m.Repo, m.Base, m.Commit)
 		return nil
 	}
-	ordered := orderByBases(moved)
+	against, err := inv.BuiltAgainst(ctx)
+	if err != nil {
+		return notNow(err)
+	}
+	ordered := orderByBases(moved, against)
 	names := make([]string, 0, len(ordered))
 	for _, e := range ordered {
 		names = append(names, e.Manifest.Module)
@@ -265,7 +269,7 @@ func (f following) SourceMoved(ctx context.Context, m link.SourceMoved) error {
 			failed = append(failed, e.Manifest.Module)
 			// A base that failed is a reason to stop: what stands on it would be built against
 			// the old one, and report success (novox/hq 04-ISSUES/131).
-			if standsOn(ordered, e.Manifest.Module) {
+			if standsOn(ordered, e.Manifest.Module, against) {
 				fmt.Printf("  stopping: %s is a base of what was still to build\n", e.Manifest.Module)
 				break
 			}
@@ -292,10 +296,13 @@ func sourceIs(s inventory.Source, m link.SourceMoved) bool {
 	return s.Ref == "" || s.Ref == m.Base
 }
 
-// orderByBases is the entries with every base before what stands on it: a module whose build names
-// another's artifact under build.on comes after that module. Entries outside the set are not
-// waited for — they are not being rebuilt. Stable for what has no order between it.
-func orderByBases(entries []inventory.Entry) []inventory.Entry {
+// orderByBases is the entries with every base before what stands on it: a module whose build stood
+// on another's artifact comes after that module. Entries outside the set are not waited for — they
+// are not being rebuilt. Stable for what has no order between it.
+//
+// `against` is what each module's newest build stood on (inventory.BuiltAgainst): the edges are
+// derived from builds, not declared, because a recorded manifest no longer carries `build.on`.
+func orderByBases(entries []inventory.Entry, against map[string][]string) []inventory.Entry {
 	inSet := map[string]bool{}
 	for _, e := range entries {
 		inSet[e.Manifest.Module] = true
@@ -309,13 +316,9 @@ func orderByBases(entries []inventory.Entry) []inventory.Entry {
 			return
 		}
 		seen[name] = true
-		if e.Manifest.Build != nil {
-			for _, on := range e.Manifest.Build.On {
-				for _, base := range entries {
-					if base.Manifest.Module != name && inSet[base.Manifest.Module] && standsOnModule(on, base.Manifest.Module) {
-						place(base, seen)
-					}
-				}
+		for _, base := range entries {
+			if base.Manifest.Module != name && inSet[base.Manifest.Module] && standsOnModule(e, base.Manifest.Module, against) {
+				place(base, seen)
 			}
 		}
 		placed[name] = true
@@ -328,26 +331,34 @@ func orderByBases(entries []inventory.Entry) []inventory.Entry {
 }
 
 // standsOn is whether anything in the set is built on the named module's artifacts.
-func standsOn(entries []inventory.Entry, module string) bool {
+func standsOn(entries []inventory.Entry, module string, against map[string][]string) bool {
 	for _, e := range entries {
-		if e.Manifest.Build == nil {
-			continue
-		}
-		for _, on := range e.Manifest.Build.On {
-			if standsOnModule(on, module) {
-				return true
-			}
+		if standsOnModule(e, module, against) {
+			return true
 		}
 	}
 	return false
 }
 
-// standsOnModule is whether a base names the module: as written in a manifest (`module`), or as
-// recorded after a build, when the mesh has replaced it with the artifact it resolved to
-// (`artifact-store://<module>/<artifact>@…`). A recorded manifest is what the catalogue holds.
-func standsOnModule(on catalogue.BuildsOn, module string) bool {
-	if on.Module == module {
-		return true
+// standsOnModule is whether an entry's build stood on the named module: by what its newest build
+// recorded it was handed (`artifact-store://<module>/<artifact>@…`, the module's own artifact), or
+// — for a module registered from a manifest and not yet built — by the base its manifest names.
+func standsOnModule(e inventory.Entry, module string, against map[string][]string) bool {
+	if e.Manifest.Module == module {
+		return false
 	}
-	return strings.HasPrefix(on.Image, "artifact-store://"+module+"/")
+	if e.Manifest.Build != nil {
+		for _, on := range e.Manifest.Build.On {
+			if on.Module == module {
+				return true
+			}
+		}
+	}
+	prefix := catalogue.ArtifactStoreScheme + module + "/"
+	for _, ref := range against[e.Manifest.Module] {
+		if strings.HasPrefix(ref, prefix) {
+			return true
+		}
+	}
+	return false
 }