feat: add set mutator

Author: oetr

selffuzz/src/test/java/com/code_intelligence/selffuzz/mutation/ArgumentsMutatorFuzzTest.java

@@ -41,6 +41,7 @@
 import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 import java.util.stream.Collectors;
 
 public class ArgumentsMutatorFuzzTest {
@@ -108,6 +109,13 @@ void fuzzListOfMaps(@WithSize(max = 4) Map<String, Integer> nullableMap) {
     }
   }
 
+  @SelfFuzzTest
+  void fuzzListOfSets(@WithSize(max = 10) @NotNull Set<@NotNull Integer> setWithSize) {
+    if (setWithSize != null) {
+      assertThat(setWithSize.size()).isAtMost(10);
+    }
+  }
+
   @SelfFuzzTest
   void fuzzListOfLists(List<@NotNull List<String>> nullableMap, List<List<Integer>> nullableList) {}
 

src/main/java/com/code_intelligence/jazzer/mutation/annotation/WithSize.java

@@ -26,10 +26,11 @@
 import java.lang.annotation.Target;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 @Target(TYPE_USE)
 @Retention(RUNTIME)
-@AppliesTo({List.class, Map.class})
+@AppliesTo({List.class, Map.class, Set.class})
 @ValidateContainerDimensions
 @PropertyConstraint
 public @interface WithSize {

src/main/java/com/code_intelligence/jazzer/mutation/mutator/collection/ChunkCrossOvers.java

@@ -22,9 +22,11 @@
 import java.util.Collection;
 import java.util.Iterator;
 import java.util.LinkedHashMap;
+import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
+import java.util.Set;
 
 final class ChunkCrossOvers {
   private ChunkCrossOvers() {}
@@ -98,6 +100,25 @@ static <K, V> void insertChunk(
     }
   }
 
+  static <K> void insertChunk(
+      Set<K> set, Set<K> otherSet, int maxSize, PseudoRandom prng, boolean hasFixedSize) {
+    int originalSize = set.size();
+    int maxChunkSize = Math.min(maxSize - originalSize, otherSet.size());
+    int chunkSize = prng.sizeInClosedRange(1, maxChunkSize, hasFixedSize);
+    int fromChunkOffset = prng.closedRange(0, otherSet.size() - chunkSize);
+    Iterator<K> fromIterator = otherSet.iterator();
+    for (int i = 0; i < fromChunkOffset; i++) {
+      fromIterator.next();
+    }
+    // insertChunk only inserts new entries and does not overwrite existing
+    // ones. As skipping those entries would lead to fewer insertions than
+    // requested, loop over the rest of the map to fill the chunk if possible.
+    while (set.size() < originalSize + chunkSize && fromIterator.hasNext()) {
+      K key = fromIterator.next();
+      set.add(key);
+    }
+  }
+
   static <K, V> void overwriteChunk(
       Map<K, V> map, Map<K, V> otherMap, PseudoRandom prng, boolean hasFixedSize) {
     onCorrespondingChunks(
@@ -117,6 +138,59 @@ static <K, V> void overwriteChunk(
         hasFixedSize);
   }
 
+  static <K> void overwriteChunk(
+      Set<K> set, Set<K> otherSet, PseudoRandom prng, boolean hasFixedSize) {
+    onCorrespondingChunks(
+        set,
+        otherSet,
+        prng,
+        (fromIterator, toIterator, chunkSize) -> {
+          // As keys can not be overwritten, only removed and new ones added, this
+          // cross over overwrites the values. Removal of keys is handled by the
+          // removeChunk mutation. Value equality is not checked here.
+          for (int i = 0; i < chunkSize; i++) {
+            K from = fromIterator.next();
+            K to = toIterator.next();
+          }
+        },
+        hasFixedSize);
+  }
+
+  static <K> void crossOverChunk(
+      Set<K> set, Set<K> otherSet, SerializingMutator<K> keyMutator, PseudoRandom prng) {
+    onCorrespondingChunks(
+        set,
+        otherSet,
+        prng,
+        (fromIterator, toIterator, chunkSize) -> {
+          Set<K> entriesToAdd = new LinkedHashSet<>(chunkSize);
+          for (int i = 0; i < chunkSize; i++) {
+            K to = toIterator.next();
+            K from = fromIterator.next();
+
+            // The entry has to be removed from the map before the cross-over, as
+            // mutating its key could cause problems in subsequent lookups.
+            // Furthermore, no new entries may be added while using the iterator,
+            // so crossed-over keys are collected for later addition.
+            toIterator.remove();
+
+            // As cross-overs do not guarantee to mutate the given object, no
+            // checks if the crossed over key already exists in the map are
+            // performed. This potentially overwrites existing entries or
+            // generates equal keys.
+            // In case of cross over this behavior is acceptable.
+            K newKey = keyMutator.crossOver(to, from, prng);
+
+            // Prevent null keys, as those are not allowed in some map implementations.
+            if (newKey != null) {
+              entriesToAdd.add(newKey);
+            }
+          }
+          set.addAll(entriesToAdd);
+        },
+        keyMutator.hasFixedSize());
+  }
+
   static <K, V> void crossOverChunk(
       Map<K, V> map,
       Map<K, V> otherMap,
@@ -198,6 +272,11 @@ private interface ChunkMapOperation<K, V> {
     void apply(Iterator<Entry<K, V>> fromIterator, Iterator<Entry<K, V>> toIterator, int chunkSize);
   }
 
+  @FunctionalInterface
+  private interface ChunkSetOperation<K> {
+    void apply(Iterator<K> fromIterator, Iterator<K> toIterator, int chunkSize);
+  }
+
   static <K, V> void onCorrespondingChunks(
       Map<K, V> map,
       Map<K, V> otherMap,
@@ -219,6 +298,27 @@ static <K, V> void onCorrespondingChunks(
     operation.apply(fromIterator, toIterator, chunkSize);
   }
 
+  static <K> void onCorrespondingChunks(
+      Set<K> set,
+      Set<K> otherSet,
+      PseudoRandom prng,
+      ChunkSetOperation<K> operation,
+      boolean hasFixedSize) {
+    int maxChunkSize = Math.min(set.size(), otherSet.size());
+    int chunkSize = prng.sizeInClosedRange(1, maxChunkSize, hasFixedSize);
+    int fromChunkOffset = prng.closedRange(0, otherSet.size() - chunkSize);
+    int toChunkOffset = prng.closedRange(0, set.size() - chunkSize);
+    Iterator<K> fromIterator = otherSet.iterator();
+    for (int i = 0; i < fromChunkOffset; i++) {
+      fromIterator.next();
+    }
+    Iterator<K> toIterator = set.iterator();
+    for (int i = 0; i < toChunkOffset; i++) {
+      toIterator.next();
+    }
+    operation.apply(fromIterator, toIterator, chunkSize);
+  }
+
   public enum CrossOverAction {
     INSERT_CHUNK,
     OVERWRITE_CHUNK,

src/main/java/com/code_intelligence/jazzer/mutation/mutator/collection/ChunkMutations.java

@@ -16,10 +16,11 @@
 
 package com.code_intelligence.jazzer.mutation.mutator.collection;
 
+import static com.code_intelligence.jazzer.mutation.support.Preconditions.require;
+
 import com.code_intelligence.jazzer.mutation.api.PseudoRandom;
 import com.code_intelligence.jazzer.mutation.api.SerializingMutator;
 import com.code_intelligence.jazzer.mutation.api.ValueMutator;
-import com.code_intelligence.jazzer.mutation.support.Preconditions;
 import java.util.AbstractList;
 import java.util.ArrayDeque;
 import java.util.ArrayList;
@@ -162,6 +163,56 @@ static <K, V, KW, VW> boolean mutateRandomKeysChunk(
     return grownBy > 0;
   }
 
+  static <K, KW> boolean mutateRandomKeysChunk(
+      Set<K> set, SerializingMutator<K> keyMutator, PseudoRandom prng) {
+    int originalSize = set.size();
+    int chunkSize = prng.sizeInClosedRange(1, originalSize, keyMutator.hasFixedSize());
+    int chunkOffset = prng.closedRange(0, originalSize - chunkSize);
+
+    // To ensure that mutating keys actually results in the set of keys changing, we keep the keys
+    // to mutate in the set, try to add new keys (that are therefore distinct from the keys to
+    // mutate) and only remove the successfully mutated keys in the end.
+    ArrayDeque<KW> keysToMutate = new ArrayDeque<>(chunkSize);
+    ArrayList<K> keysToRemove = new ArrayList<>(chunkSize);
+    // get the set iterator
+    Iterator<K> it = set.iterator();
+    for (int i = 0; i < chunkOffset; i++) {
+      it.next();
+    }
+    for (int i = chunkOffset; i < chunkOffset + chunkSize; i++) {
+      K entry = it.next();
+      // ArrayDeque cannot hold null elements, which requires us to replace null with a sentinel.
+      // Also detach the key as keys may be mutable and mutation could destroy them.
+      keysToMutate.add(boxNull(keyMutator.detach(entry)));
+      keysToRemove.add(entry);
+    }
+
+    Consumer<K> addIfNew =
+        key -> {
+          int sizeBeforeAdd = set.size();
+          set.add(key);
+          // The mutated key was new, try to mutate and add the next in line.
+          if (set.size() > sizeBeforeAdd) {
+            keysToMutate.removeFirst();
+          }
+        };
+    Supplier<K> nextCandidate =
+        () -> {
+          // Mutate the next candidate in the queue.
+          K candidate = keyMutator.mutate(unboxNull(keysToMutate.removeFirst()), prng);
+          keysToMutate.addFirst(boxNull(candidate));
+          return candidate;
+        };
+
+    growBy(set, addIfNew, chunkSize, nextCandidate);
+    // Remove the original keys that were successfully mutated into new keys. Since the original
+    // keys have been kept in the set up to this point, all keys added were successfully mutated to
+    // be unequal to the original keys.
+    int grownBy = set.size() - originalSize;
+    keysToRemove.stream().limit(grownBy).forEach(set::remove);
+    return grownBy > 0;
+  }
+
   public static <K, V> void mutateRandomValuesChunk(
       Map<K, V> map, ValueMutator<V> valueMutator, PseudoRandom prng) {
     Collection<Map.Entry<K, V>> collection = map.entrySet();
@@ -182,7 +233,7 @@ public static <K, V> void mutateRandomValuesChunk(
   static <T> boolean growBy(
       Set<T> set, Consumer<T> addIfNew, int delta, Supplier<T> candidateSupplier) {
     int oldSize = set.size();
-    Preconditions.require(delta >= 0);
+    require(delta >= 0);
 
     final int targetSize = oldSize + delta;
     int remainingAttempts = MAX_FAILED_INSERTION_ATTEMPTS;

src/main/java/com/code_intelligence/jazzer/mutation/mutator/collection/CollectionMutators.java

@@ -23,6 +23,10 @@ public final class CollectionMutators {
   private CollectionMutators() {}
 
   public static Stream<MutatorFactory> newFactories() {
-    return Stream.of(new ListMutatorFactory(), new MapMutatorFactory(), new ArrayMutatorFactory());
+    return Stream.of(
+        new ListMutatorFactory(),
+        new MapMutatorFactory(),
+        new SetMutatorFactory(),
+        new ArrayMutatorFactory());
   }
 }