Index sequence assembly and history lookups

internal/engine/compose.go

@@ -59,6 +59,7 @@ func cloneComposedDocument(base *composedDocument) *composedDocument {
 }
 
 type compositionClaim struct {
+	node        *document.Node // borrowed immutable contribution, not the assembly tree
 	path        Path
 	kind        document.Kind
 	location    Location
@@ -121,7 +122,7 @@ func composeDocumentsWithPolicy(policy sequencePolicy, inputs ...*document.Node)
 		return nil, []Diagnostic{compositionConflictDiagnostic(claim.path, claims)}
 	}
 
-	validated, ranges, diagnostics := validateRegisteredSequences(inputs, collected.ordered, policy)
+	validated, ranges, diagnostics := validateRegisteredSequences(collected.ordered, policy)
 	if len(diagnostics) != 0 {
 		return nil, diagnostics
 	}
@@ -133,12 +134,13 @@ func composeDocumentsWithPolicy(policy sequencePolicy, inputs ...*document.Node)
 	}
 	applications := make([]historyApplication, 0, len(inputs))
 	seenSequences := make(map[string]bool)
+	rangesBySource := make([][]sequenceRange, len(inputs))
+	for _, assigned := range ranges {
+		rangesBySource[assigned.sourceIndex] = append(rangesBySource[assigned.sourceIndex], assigned)
+	}
 	for sourceIndex, input := range inputs {
 		application := historyApplication{layer: LayerBase, value: input}
-		for _, assigned := range ranges {
-			if assigned.sourceIndex != sourceIndex {
-				continue
-			}
+		for _, assigned := range rangesBySource[sourceIndex] {
 			pointer := assigned.path.String()
 			mode := sequenceHistoryAppend
 			if !seenSequences[pointer] {
@@ -149,6 +151,7 @@ func composeDocumentsWithPolicy(policy sequencePolicy, inputs ...*document.Node)
 				path: assigned.path.clone(), mode: mode, offset: assigned.start, length: assigned.end - assigned.start,
 			})
 		}
+		application.sequencesByPath = indexSequenceHistoryContributions(application.sequences)
 		applications = append(applications, application)
 	}
 	origins := projectedCompositionOrigins(inputs, ranges)
@@ -183,6 +186,7 @@ func completeCompositionOrigins(node *document.Node, path Path, origins map[stri
 
 func (c *compositionClaims) append(node *document.Node, path Path, sourceIndex int) {
 	claim := compositionClaim{
+		node:        node,
 		path:        path.clone(),
 		kind:        node.Kind,
 		location:    publicLocation(node.Location),
@@ -213,7 +217,7 @@ type validatedSequence struct {
 	items []*document.Node
 }
 
-func validateRegisteredSequences(inputs []*document.Node, claims []compositionClaim, policy sequencePolicy) (map[string]map[int]validatedSequence, []sequenceRange, []Diagnostic) {
+func validateRegisteredSequences(claims []compositionClaim, policy sequencePolicy) (map[string]map[int]validatedSequence, []sequenceRange, []Diagnostic) {
 	itemsByPath := make(map[string]map[int]validatedSequence)
 	identitiesByPath := make(map[string]map[string]Location)
 	lengthsByPath := make(map[string]int)
@@ -226,10 +230,7 @@ func validateRegisteredSequences(inputs []*document.Node, claims []compositionCl
 		if !registered {
 			continue
 		}
-		node, ok := documentAtPath(inputs[claim.sourceIndex], claim.path)
-		if !ok || node.Kind != document.Sequence {
-			continue
-		}
+		node := claim.node
 		pathKey := claim.path.String()
 		identities := identitiesByPath[pathKey]
 		if identities == nil {
@@ -389,6 +390,19 @@ type sequenceRangeKey struct {
 	path        string
 }
 
+type sequenceRangeIndex map[sequenceRangeKey]sequenceRange
+
+func indexSequenceRanges(ranges []sequenceRange) sequenceRangeIndex {
+	if len(ranges) == 0 {
+		return nil
+	}
+	index := make(sequenceRangeIndex, len(ranges))
+	for _, assigned := range ranges {
+		index[sequenceRangeKey{sourceIndex: assigned.sourceIndex, path: assigned.path.String()}] = assigned
+	}
+	return index
+}
+
 // Keep local paths for matching Stage 2 ranges and effective paths for emitted
 // evidence. The paths are transformed segment by segment; pointer strings are
 // only used as map keys after projection is complete.