Crash Every Day on Android M! java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.lang.String.equals(java.lang.Object)

[Jacksgong]

• Android M
• Nexus 5
• targetSdkVersion 23
• compileSdkVersion 23
• multiDexEnabled true

Crash every day:

1.3.1:

 if (/** npe here!!!! **/keyCandidate.equals(key)) {
        return (IObject) weakRef.resolveValue("referent");
      }

Detail:

// HeapAnalyzer#findLeakingReference by 1.3.1
private IObject findLeakingReference(String key, ISnapshot snapshot) throws SnapshotException {
    Collection<IClass> refClasses =
        snapshot.getClassesByName(KeyedWeakReference.class.getName(), false);

    if (refClasses.size() != 1) {
      throw new IllegalStateException(
          "Expecting one class for " + KeyedWeakReference.class.getName() + " in " + refClasses);
    }

    IClass refClass = refClasses.iterator().next();

    int[] weakRefInstanceIds = refClass.getObjectIds();

    for (int weakRefInstanceId : weakRefInstanceIds) {
      IObject weakRef = snapshot.getObject(weakRefInstanceId);
      String keyCandidate =
          PrettyPrinter.objectAsString((IObject) weakRef.resolveValue("key"), 100);
      if (/** npe here **/keyCandidate.equals(key)) {
        return (IObject) weakRef.resolveValue("referent");
      }
    }
    throw new IllegalStateException("Could not find weak reference with key " + key);
  }

// PrettyPrinter.objectAsString by 1.3.1
public static String objectAsString(IObject stringObject, int limit) throws SnapshotException {
    Integer count = (Integer) stringObject.resolveValue("count"); 
    if (count == null) return null;
    if (count.intValue() == 0) return ""; 

    IPrimitiveArray charArray = (IPrimitiveArray) stringObject.resolveValue("value"); 
    if (charArray == null) return null; // return null

    Integer offset = (Integer) stringObject.resolveValue("offset"); 
    if (offset == null) return null; // return null!

    return arrayAsString(charArray, offset, count, limit);
  }

public static String arrayAsString(IPrimitiveArray charArray, int offset, int count, int limit) {
    if (charArray.getType() != IObject.Type.CHAR) return null; // return null

    int length = charArray.getLength();

    int contentToRead = count <= limit ? count : limit;
    if (contentToRead > length - offset) contentToRead = length - offset;

    char[] value;
    if (offset == 0 && length == contentToRead) {
      value = (char[]) charArray.getValueArray();
    } else {
      value = (char[]) charArray.getValueArray(offset, contentToRead);
    }

    if (value == null) return null; // return null

    StringBuilder result = new StringBuilder(value.length);
    for (int ii = 0; ii < value.length; ii++) {
      char val = value[ii];
      if (val >= 32 && val < 127) {
        result.append(val);
      } else {
        result.append("\\u").append(String.format("%04x", 0xFFFF & val)); 
      }
    }
    if (limit < count) result.append("..."); //$NON-NLS-1$
    return result.toString();
  }

  private PrettyPrinter() {
  }

[Jacksgong]

Last code on master branch fix such npe, but not release... and When?

private Instance findLeakingReference(String key, Snapshot snapshot) {
    ClassObj refClass = snapshot.findClass(KeyedWeakReference.class.getName());
    List<String> keysFound = new ArrayList<>();
    for (Instance instance : refClass.getInstancesList()) {
      List<ClassInstance.FieldValue> values = classInstanceValues(instance);
      String keyCandidate = asString(fieldValue(values, "key"));
      if (keyCandidate.equals(key)) {
        return fieldValue(values, "referent");
      }
      keysFound.add(keyCandidate);
    }
    throw new IllegalStateException(
        "Could not find weak reference with key " + key + " in " + keysFound);
  }

static String asString(Object stringObject) {
    Instance instance = (Instance) stringObject;
    List<ClassInstance.FieldValue> values = classInstanceValues(instance);

    Integer count = fieldValue(values, "count");
    Object value = fieldValue(values, "value");
    Integer offset;
    ArrayInstance charArray;
    if (isCharArray(value)) {
      charArray = (ArrayInstance) value;
      offset = fieldValue(values, "offset");
    } else {
      // In M preview 2+, the underlying char buffer resides in the heap with ID equalling the
      // String's ID + 16.
      // https://android-review.googlesource.com/#/c/160380/2/android/src/com/android/tools/idea/
      // editors/hprof/descriptors/InstanceFieldDescriptorImpl.java
      Heap heap = instance.getHeap();
      Instance inlineInstance = heap.getInstance(instance.getId() + 16);
      if (isCharArray(inlineInstance)) {
        charArray = (ArrayInstance) inlineInstance;
        offset = 0;
      } else {
        throw new UnsupportedOperationException("Could not find char array in " + instance);
      }
    }
    checkNotNull(count, "count");
    checkNotNull(charArray, "charArray");
    checkNotNull(offset, "offset");

    if (count == 0) {
      return "";
    }

    char[] chars = charArray.asCharArray(offset, count);

    return new String(chars);
  }

[cristiangarciascmspain]

another issue related to #267

[jrodbx]

Duplicate of #341