Retain ordered acquisition scopes

internal/engine/load_input.go

@@ -11,12 +11,58 @@ type assembledInput struct {
 	parsed       parsedSource
 	document     *document.Node
 	composition  *composedDocument
+	acquisition  []acquisitionScope
 	inheritance  *inheritanceScope
 	sources      []SourceInfo
 	contexts     map[string]ResourceContext
 	versionState *sourceVersionState
 }
 
+// acquiredContribution keeps a source-local payload beside its placed document.
+// The latter is used for composition; the former preserves the acquisition
+// boundary for later scoped assembly and evidence.
+type acquiredContribution struct {
+	source              SourceInfo
+	payload             *document.Node
+	document            *document.Node
+	destination         Path
+	relativeDestination Path
+	processing          *sourceVersionProcessingResult
+}
+
+// acquisitionScope is the ordered strict mapping scope produced by one input
+// and its ordinary imports.
+type acquisitionScope struct {
+	destination   Path
+	contributions []acquiredContribution
+}
+
+func cloneAcquisitionScope(scope acquisitionScope) acquisitionScope {
+	cloned := acquisitionScope{destination: scope.destination.clone()}
+	if scope.contributions != nil {
+		cloned.contributions = make([]acquiredContribution, len(scope.contributions))
+		for index, contribution := range scope.contributions {
+			cloned.contributions[index] = acquiredContribution{
+				source: cloneSourceInfo(contribution.source), payload: contribution.payload,
+				document: contribution.document, destination: contribution.destination.clone(),
+				relativeDestination: contribution.relativeDestination.clone(), processing: contribution.processing,
+			}
+		}
+	}
+	return cloned
+}
+
+func cloneAcquisitionScopes(scopes []acquisitionScope) []acquisitionScope {
+	if scopes == nil {
+		return nil
+	}
+	cloned := make([]acquisitionScope, len(scopes))
+	for index, scope := range scopes {
+		cloned[index] = cloneAcquisitionScope(scope)
+	}
+	return cloned
+}
+
 func assembleBaseInput[T any](source Source, options Options[T]) (assembledInput, []Diagnostic) {
 	return assembleBaseInputTracked(source, options, Path{}, &importAccounting{}, nil, nil)
 }
@@ -76,6 +122,7 @@ func assembleBaseInputTrackedForRole[T any](source Source, options Options[T], d
 		if len(diagnostics) != 0 {
 			return input, diagnostics
 		}
+		input.acquisition = cloneAcquisitionScopes(input.composition.acquisition)
 		input.document = input.composition.root
 	} else {
 		input.sources = sourceInfos(parsed.source)
@@ -93,7 +140,15 @@ func assembleBaseInputTrackedForRole[T any](source Source, options Options[T], d
 		if err != nil {
 			return input, []Diagnostic{sourceDiagnostic(CodeSourceLimitExceeded, parsed.source.ID, "configuration exceeds the source depth or node limit after destination placement")}
 		}
+		localPayload := input.document
 		input.document = placed
+		input.acquisition = []acquisitionScope{{
+			destination: destination.clone(),
+			contributions: []acquiredContribution{{
+				source: cloneSourceInfo(*parsed.source), payload: localPayload,
+				document: placed, destination: destination.clone(), processing: versionProcessing,
+			}},
+		}}
 		rawNodes := countInputNodes(parsed.document)
 		placementNodes := destinationWrapperNodeCount(destination)
 		if accounting.sources+1 > limits.sources || accounting.bytes+parsed.bytes > limits.bytes || accounting.nodes+rawNodes+placementNodes > limits.nodes {
@@ -185,5 +240,6 @@ func compositionForInput(input assembledInput) (*composedDocument, []Diagnostic)
 	}
 	composition.inputBytes = input.parsed.bytes
 	composition.inputNodes = countInputNodes(input.document)
+	composition.acquisition = cloneAcquisitionScopes(input.acquisition)
 	return composition, nil
 }