Retire obsolete collection identity before replacement agreement

internal/engine/compose.go

@@ -293,14 +293,16 @@ func resolveStrictCollectionPolicies(
 ) (map[string][]string, collectionPolicyScope, []Diagnostic) {
 	paths := make([]Path, 0, len(claims)+len(declarations))
 	seen := make(map[string]bool, len(claims)+len(declarations))
-	sequencePresent := make(map[string]bool)
+	valuePresent := make(map[string]bool)
 	declarationsByPath := make(map[string][]sequenceDeclarationSpec, len(declarations))
 	for _, claim := range claims {
+		if len(lower.collections) != 0 {
+			valuePresent[claim.path.String()] = true
+		}
 		if claim.kind != document.Sequence {
 			continue
 		}
 		key := claim.path.String()
-		sequencePresent[key] = true
 		if !seen[key] {
 			seen[key] = true
 			paths = append(paths, claim.path.clone())
@@ -316,7 +318,10 @@ func resolveStrictCollectionPolicies(
 	}
 
 	identityFieldsByPath := make(map[string][]string)
-	effectiveLower := cloneCollectionPolicyScope(lower)
+	effectiveLower := lower
+	if len(lower.collections) != 0 {
+		effectiveLower, _ = lowerCollectionPoliciesForClaims(lower, claims, declarationsByPath, applicationPolicy)
+	}
 	collectionPolicies := cloneCollectionPolicyScope(effectiveLower)
 	var diagnostics []Diagnostic
 	for _, path := range paths {
@@ -331,28 +336,6 @@ func resolveStrictCollectionPolicies(
 		}
 		applicationIdentity, _ := applicationPolicy.identityFieldsAt(path)
 
-		// A replacing value drops the old YAML identity before this tier's
-		// peers are checked. The explicit operation itself remains applicable.
-		selectedMode := sequenceMode(0)
-		for _, declaration := range currentDeclarations {
-			if declaration.modePresent {
-				selectedMode = declaration.mode
-				break
-			}
-		}
-		if selectedMode == 0 && lowerPolicy != nil && lowerPolicy.explicitModePresent {
-			selectedMode = lowerPolicy.explicitMode
-		}
-		if sequencePresent[key] && selectedMode == sequenceModeReplace && lowerPolicy != nil {
-			lowerPolicy.identityFields = nil
-			lowerPolicy.identityPresent = false
-			lowerPolicy.identityLocation = nil
-			lowerPolicy.recordOrder = nil
-			lowerPolicy.recordPolicies = nil
-			effectiveLower.retireCollectionPoliciesAtOrBelow(path)
-			collectionPolicies.retireCollectionPoliciesAtOrBelow(path)
-		}
-
 		resolution, found := resolveCollectionPolicy(path, currentDeclarations, applicationIdentity, lowerPolicy)
 		if len(found) != 0 {
 			diagnostics = append(diagnostics, found...)
@@ -363,7 +346,7 @@ func resolveStrictCollectionPolicies(
 		}
 
 		policyForPath := resolution.policy
-		if hasLower && !sequencePresent[key] {
+		if hasLower && !valuePresent[key] {
 			// A declaration without a new value changes policy metadata but
 			// leaves retained record ownership untouched.
 			policyForPath = cloneCollectionPolicy(lowerEntry.policy)