Address PR feedback

Author: mtdowling

smithy-rules-engine/src/main/java/software/amazon/smithy/rulesengine/logic/bdd/BddBuilder.java

@@ -30,9 +30,10 @@ final class BddBuilder {
     private static final int FALSE_REF = -1;
 
     // Node storage: three separate arrays
-    private int[] variables = new int[1024];
-    private int[] highs = new int[1024];
-    private int[] lows = new int[1024];
+    private static final int INITIAL_SIZE = 256;
+    private int[] variables = new int[INITIAL_SIZE];
+    private int[] highs = new int[INITIAL_SIZE];
+    private int[] lows = new int[INITIAL_SIZE];
     private int nodeCount;
 
     // Unique tables for node deduplication and ITE caching
@@ -48,7 +49,7 @@ final class BddBuilder {
     public BddBuilder() {
         this.nodeCount = 1;
         this.uniqueTable = new UniqueTable();
-        this.iteCache = new UniqueTable(4096); // Larger initial capacity for ITE cache
+        this.iteCache = new UniqueTable(1024);
         initializeTerminalNode();
     }
 

smithy-rules-engine/src/main/java/software/amazon/smithy/rulesengine/logic/bdd/BddCompiler.java

@@ -90,11 +90,9 @@ private int convertCfgToBdd(CfgNode cfgNode) {
         int result;
         if (cfgNode == null) {
             result = bddBuilder.makeResult(noMatchIndex);
-
         } else if (cfgNode instanceof ResultNode) {
             Rule rule = ((ResultNode) cfgNode).getResult();
             result = bddBuilder.makeResult(getOrCreateResultIndex(rule));
-
         } else {
             ConditionNode cn = (ConditionNode) cfgNode;
             ConditionReference ref = cn.getCondition();

smithy-rules-engine/src/main/java/software/amazon/smithy/rulesengine/logic/bdd/BddEquivalenceChecker.java

@@ -27,7 +27,7 @@
  *
  * <p>This verifier uses structural equivalence checking to ensure that both representations produce the same result.
  * When the BDD has fewer than 20 conditions, the checking is exhaustive. When there are more, random samples are
- * checked up the earlier of max samples being reached, or the max duration being reached.
+ * checked up the earlier of max samples being reached or the max duration being reached.
  */
 public final class BddEquivalenceChecker {
 
@@ -210,11 +210,12 @@ private void verifyCriticalCases() {
             verifyCase(allTrue ^ (1L << i));
         }
 
-        // Alternating patterns
+        // Alternating patterns: 0101... (even conditions false, odd true)
         if (!hasEitherLimitBeenExceeded()) {
             verifyCase(0x5555555555555555L & ((1L << bdd.getConditionCount()) - 1));
         }
 
+        // Pattern: 1010... (even conditions true, odd false)
         if (!hasEitherLimitBeenExceeded()) {
             verifyCase(0xAAAAAAAAAAAAAAAAL & ((1L << bdd.getConditionCount()) - 1));
         }

smithy-rules-engine/src/main/java/software/amazon/smithy/rulesengine/logic/bdd/BddTrait.java

@@ -15,6 +15,7 @@
 import java.util.List;
 import java.util.Set;
 import java.util.function.Function;
+import software.amazon.smithy.model.node.ArrayNode;
 import software.amazon.smithy.model.node.Node;
 import software.amazon.smithy.model.node.ObjectNode;
 import software.amazon.smithy.model.shapes.ShapeId;
@@ -130,14 +131,14 @@ protected Node createNode() {
         ObjectNode.Builder builder = ObjectNode.builder();
         builder.withMember("parameters", parameters.toNode());
 
-        List<Node> conditionNodes = new ArrayList<>();
+        ArrayNode.Builder conditionBuilder = ArrayNode.builder();
         for (Condition c : conditions) {
-            conditionNodes.add(c.toNode());
+            conditionBuilder.withValue(c);
         }
-        builder.withMember("conditions", Node.fromNodes(conditionNodes));
+        builder.withMember("conditions", conditionBuilder.build());
 
         // Results (skip NoMatchRule at index 0 for serialization)
-        List<Node> resultNodes = new ArrayList<>();
+        ArrayNode.Builder resultBuilder = ArrayNode.builder();
         if (!results.isEmpty() && !(results.get(0) instanceof NoMatchRule)) {
             throw new IllegalStateException("BDD must always have a NoMatchRule as the first result");
         }
@@ -146,9 +147,9 @@ protected Node createNode() {
             if (result instanceof NoMatchRule) {
                 throw new IllegalStateException("NoMatch rules can only appear at rule index 0. Found at index " + i);
             }
-            resultNodes.add(result.toNode());
+            resultBuilder.withValue(result);
         }
-        builder.withMember("results", Node.fromNodes(resultNodes));
+        builder.withMember("results", resultBuilder.build());
 
         builder.withMember("root", bdd.getRootRef());
         builder.withMember("nodeCount", bdd.getNodeCount());