Enforce the retained history node limit

internal/engine/history.go

@@ -40,6 +40,86 @@ func (c *retainedNodeCounter) add(root *document.Node) bool {
 	return true
 }
 
+func (c *retainedNodeCounter) canAddClones(roots []*document.Node, copies int) bool {
+	if c == nil || c.limit < 0 {
+		return true
+	}
+	remaining := c.limit - c.count
+	if remaining < 0 {
+		return false
+	}
+	for copyIndex := 0; copyIndex < copies; copyIndex++ {
+		for _, root := range roots {
+			count, within := documentCloneNodeCount(root, remaining)
+			if !within {
+				return false
+			}
+			remaining -= count
+		}
+	}
+	return true
+}
+
+func documentCloneNodeCount(root *document.Node, limit int) (int, bool) {
+	if root == nil {
+		return 0, true
+	}
+	count := 0
+	stack := []*document.Node{root}
+	for len(stack) != 0 {
+		node := stack[len(stack)-1]
+		stack = stack[:len(stack)-1]
+		if node == nil {
+			continue
+		}
+		count++
+		if count > limit {
+			return 0, false
+		}
+		for _, entry := range node.Mapping {
+			stack = append(stack, entry.Value)
+		}
+		stack = append(stack, node.Sequence...)
+	}
+	return count, true
+}
+
+func addInspectionHistory(counter *retainedNodeCounter, inspection *Inspection) bool {
+	if inspection == nil {
+		return false
+	}
+	for _, root := range []*document.Node{inspection.baseline, inspection.input, inspection.final, inspection.preCLI} {
+		if !counter.add(root) {
+			return false
+		}
+	}
+	for _, application := range inspection.applications {
+		if !counter.add(application.value) {
+			return false
+		}
+	}
+	for _, application := range inspection.postDecodeApps {
+		if !counter.add(application.value) {
+			return false
+		}
+	}
+	for _, snapshots := range [][]resolutionSnapshot{inspection.resolution, inspection.resolutionReplay} {
+		for _, snapshot := range snapshots {
+			if !counter.add(snapshot.before) || !counter.add(snapshot.after) {
+				return false
+			}
+		}
+	}
+	for _, operations := range [][]inheritanceOperation{inspection.inheritance, inspection.metadata.inheritance} {
+		for _, operation := range operations {
+			if !counter.add(operation.parent) || !counter.add(operation.effective) {
+				return false
+			}
+		}
+	}
+	return true
+}
+
 // History applications borrow immutable policy-validated input trees. Metadata
 // records answer presence and origin queries; replay reconstructs value changes.
 // Replay reconciles with canonical decoding, applies supplied CLI contributions,
@@ -499,66 +579,3 @@ func replaceHistoryPath(root **document.Node, path Path, replacement *document.N
 		}
 	}
 }
-
-func historyNodesWithinLimit(baseline, input, final *document.Node, applications []historyApplication, resolutions []resolutionSnapshot, inherited ...*inheritanceScope) bool {
-	return historyNodesWithin(historyNodeLimit, baseline, input, final, applications, resolutions, inherited...)
-}
-
-func historyNodesWithin(limit int, baseline, input, final *document.Node, applications []historyApplication, resolutions []resolutionSnapshot, inherited ...*inheritanceScope) bool {
-	seen := make(map[*document.Node]bool)
-	count := 0
-	var visit func(*document.Node) bool
-	visit = func(node *document.Node) bool {
-		if node == nil || seen[node] {
-			return true
-		}
-		seen[node] = true
-		count++
-		if count > limit {
-			return false
-		}
-		for _, entry := range node.Mapping {
-			if !visit(entry.Value) {
-				return false
-			}
-		}
-		for _, child := range node.Sequence {
-			if !visit(child) {
-				return false
-			}
-		}
-		return true
-	}
-	if !visit(baseline) || !visit(input) || !visit(final) {
-		return false
-	}
-	for _, application := range applications {
-		if !visit(application.value) {
-			return false
-		}
-	}
-	for _, resolution := range resolutions {
-		if !visit(resolution.before) || !visit(resolution.after) {
-			return false
-		}
-	}
-	for _, expansion := range inherited {
-		if expansion == nil {
-			continue
-		}
-		if !visit(expansion.root) {
-			return false
-		}
-		for _, operation := range expansion.operations {
-			if !visit(operation.parent) || !visit(operation.effective) {
-				return false
-			}
-		}
-		for _, replacement := range expansion.replacements {
-			if !visit(replacement.before) || !visit(replacement.after) {
-				return false
-			}
-		}
-	}
-	return true
-}