Drop what a send carried from the node row (migration 0109) and read an image list from the compositions (release 6, issue 1945 B8)

cmd/mesh-controller/registry_verbs_test.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	sdkdelivery "git.novox.be/novox/mesh-sdk/go/delivery"
 	"net/http"
 	"net/http/httptest"
 	"slices"
@@ -229,3 +230,35 @@ func TestImagesAreEveryContainerImageOfTheDeclarationAndOfWhatWasSent(t *testing
 		t.Errorf("with nothing sent yet: %+v %v", none, err)
 	}
 }
+
+// **`images` reads what a node applies from its compositions** (ADR 0539 §2, issue 1945 B8): the containers among the
+// resources of the values kept in its bucket, whatever module and fingerprint; none kept is not known.
+func TestImagesAreReadFromTheCompositionsAMachineKeeps(t *testing.T) {
+	file := json.RawMessage(`{"id":"web.config","type":"file","module":"web","path":"/etc/web","content":"x"}`)
+	box := json.RawMessage(`{"id":"web.server","type":"container","name":"web","module":"web","image":"registry/web@sha256:` + strings.Repeat("a", 64) + `"}`)
+	other := json.RawMessage(`{"id":"db.server","type":"container","name":"db","module":"db","image":"registry/db@sha256:` + strings.Repeat("b", 64) + `"}`)
+	encode := func(module string, fp string, resources ...json.RawMessage) []byte {
+		v, err := sdkdelivery.EncodeComposed(sdkdelivery.Composed{Node: "anchor", Module: module, FP: fp, Resources: resources})
+		if err != nil {
+			t.Fatal(err)
+		}
+		return v
+	}
+	web := encode("web", sdkdelivery.SourcePrefix2+strings.Repeat("1", 64), file, box)
+	db := encode("db", sdkdelivery.SourcePrefix2+strings.Repeat("2", 64), other)
+
+	got, kept, err := imagesOfCompositions([][]byte{web, db})
+	if err != nil || !kept || len(got) != 2 {
+		t.Fatalf("images %+v kept %v: %v", got, kept, err)
+	}
+	answer, err := imagesOf("anchor", nil, got, kept)
+	if err != nil || len(answer.Images) != 2 || !answer.SentKnown {
+		t.Fatalf("the answer %+v: %v", answer, err)
+	}
+	if none, kept, err := imagesOfCompositions(nil); err != nil || kept || len(none) != 0 {
+		t.Fatalf("no composition kept: %+v %v %v", none, kept, err)
+	}
+	if _, _, err := imagesOfCompositions([][]byte{[]byte("nope")}); err == nil {
+		t.Fatal("an unreadable composition was read as holding no image")
+	}
+}