Merge pull request 'A collision is two places, not two spellings' (#71) from fix/collisions-compare-placed-paths into main

internal/catalogue/dir_into_test.go

@@ -221,6 +221,28 @@ func TestPlaceIsValidatedAtTheManifest(t *testing.T) {
 	}
 }
 
+func TestTwoModulesPlacedRootsAreNoCollision(t *testing.T) {
+	a := Manifest{Module: "gitea", Resources: []map[string]any{
+		{"id": "state", "type": "directory", "place": "."},
+		{"id": "env", "type": "file", "path": "${dir:state}/server.env", "content": ""},
+	}}
+	b := Manifest{Module: "nextcloud", Resources: []map[string]any{
+		{"id": "state", "type": "directory", "place": "."},
+		{"id": "env", "type": "file", "path": "${dir:state}/server.env", "content": ""},
+	}}
+	if got := checkResources([]Manifest{a, b}); len(got) != 0 {
+		t.Fatalf("alike templates are different places; got %v", got)
+	}
+	// And the real collision is still caught: a module stating another's placed root.
+	c := Manifest{Module: "squatter", Resources: []map[string]any{
+		{"id": "nest", "type": "directory", "path": "/var/lib/gitea"},
+	}}
+	got := checkResources([]Manifest{a, c})
+	if len(got) != 1 || !strings.Contains(got[0], `"/var/lib/gitea"`) {
+		t.Fatalf("a stated path on a placed root collides; got %v", got)
+	}
+}
+
 func shallowCopy(resource map[string]any) map[string]any {
 	copied := map[string]any{}
 	for k, v := range resource {

internal/catalogue/resolve.go

@@ -705,11 +705,30 @@ func checkResources(modules []Manifest) []string {
 	ownedPath := map[string]string{} // path → owning module, for the access check below
 
 	for _, m := range modules {
+		// Compared placed, not as written (novox/hq ADR 0112): ${dir:state} is the same six
+		// characters in every module and a different directory in each — two modules' templates
+		// being spelled alike is not two modules owning one path. The default root serves the
+		// comparison: a collision is within one node, and any one root keeps distinct modules'
+		// places distinct. A reference that cannot be placed is left as written — naming what
+		// does not exist is the manifest's own problem, refused where it was made.
+		dirs := dirsFor(m, Rendering{})
 		for _, r := range m.Resources {
 			for _, field := range []string{"path", "unit", "name", "package"} {
 				value, ok := r[field].(string)
 				if !ok || value == "" {
-					continue
+					if field == "path" && fmt.Sprint(r["type"]) == "directory" {
+						// A pathless directory owns its placed path — a module stating that
+						// very path is exactly the collision this exists to catch.
+						value = dirs[fmt.Sprint(r["id"])]
+					}
+					if value == "" {
+						continue
+					}
+				}
+				if field == "path" {
+					if placed, err := dirFill(value, dirs, m.Module); err == nil {
+						value = placed
+					}
 				}
 				key := field + " " + value
 				if other, taken := owner[key]; taken && other != m.Module {