Program: 87424
Project: 87424
Buggy source:
/** 
 * Handle a press on the backspace key.
 * @param settingsValues The current settings values.
 * @param spaceState The space state at start of this batch edit.
 */
private void handleBackspace(final SettingsValues settingsValues,final int spaceState,final LatinIME.UIHandler handler,final KeyboardSwitcher keyboardSwitcher){
  mSpaceState=SpaceState.NONE;
  final int deleteCountAtStart=mDeleteCount;
  mDeleteCount++;
  handler.postUpdateShiftState();
  if (mWordComposer.isCursorFrontOrMiddleOfComposingWord()) {
    resetEntireInputState(settingsValues,mConnection.getExpectedSelectionStart(),mConnection.getExpectedSelectionEnd());
  }
  if (mWordComposer.isComposingWord()) {
    if (mWordComposer.isBatchMode()) {
      if (ProductionFlag.USES_DEVELOPMENT_ONLY_DIAGNOSTICS) {
        final String word=mWordComposer.getTypedWord();
        ResearchLogger.latinIME_handleBackspace_batch(word,1);
      }
      final String rejectedSuggestion=mWordComposer.getTypedWord();
      mWordComposer.reset();
      mWordComposer.setRejectedBatchModeSuggestion(rejectedSuggestion);
    }
 else {
      mWordComposer.deleteLast();
    }
    mConnection.setComposingText(getTextWithUnderline(mWordComposer.getTypedWord()),1);
    handler.postUpdateSuggestionStrip();
    if (!mWordComposer.isComposingWord()) {
      keyboardSwitcher.updateShiftState();
    }
  }
 else {
    if (mLastComposedWord.canRevertCommit()) {
      if (settingsValues.mIsInternal) {
        LatinImeLoggerUtils.onAutoCorrectionCancellation();
      }
      revertCommit(settingsValues,handler);
      return;
    }
    if (mEnteredText != null && mConnection.sameAsTextBeforeCursor(mEnteredText)) {
      mConnection.deleteSurroundingText(mEnteredText.length(),0);
      if (ProductionFlag.USES_DEVELOPMENT_ONLY_DIAGNOSTICS) {
        ResearchLogger.latinIME_handleBackspace_cancelTextInput(mEnteredText);
      }
      mEnteredText=null;
      return;
    }
    if (SpaceState.DOUBLE == spaceState) {
      handler.cancelDoubleSpacePeriodTimer();
      if (mConnection.revertDoubleSpacePeriod()) {
        return;
      }
    }
 else     if (SpaceState.SWAP_PUNCTUATION == spaceState) {
      if (mConnection.revertSwapPunctuation()) {
        return;
      }
    }
    if (mConnection.hasSelection()) {
      final int numCharsDeleted=mConnection.getExpectedSelectionEnd() - mConnection.getExpectedSelectionStart();
      mConnection.setSelection(mConnection.getExpectedSelectionEnd(),mConnection.getExpectedSelectionEnd());
      mConnection.deleteSurroundingText(numCharsDeleted,0);
      if (ProductionFlag.USES_DEVELOPMENT_ONLY_DIAGNOSTICS) {
        ResearchLogger.latinIME_handleBackspace(numCharsDeleted,false);
      }
    }
 else {
      if (Constants.NOT_A_CURSOR_POSITION == mConnection.getExpectedSelectionEnd()) {
        Log.e(TAG,"String_Node_Str");
      }
      if (settingsValues.isBeforeJellyBean() || settingsValues.mInputAttributes.isTypeNull()) {
        sendDownUpKeyEvent(KeyEvent.KEYCODE_DEL);
        if (mDeleteCount > Constants.DELETE_ACCELERATE_AT) {
          sendDownUpKeyEvent(KeyEvent.KEYCODE_DEL);
        }
      }
 else {
        final int codePointBeforeCursor=mConnection.getCodePointBeforeCursor();
        if (codePointBeforeCursor == Constants.NOT_A_CODE) {
          mConnection.deleteSurroundingText(1,0);
          return;
        }
        final int lengthToDelete=Character.isSupplementaryCodePoint(codePointBeforeCursor) ? 2 : 1;
        mConnection.deleteSurroundingText(lengthToDelete,0);
        if (ProductionFlag.USES_DEVELOPMENT_ONLY_DIAGNOSTICS) {
          ResearchLogger.latinIME_handleBackspace(lengthToDelete,true);
        }
        if (mDeleteCount > Constants.DELETE_ACCELERATE_AT) {
          final int codePointBeforeCursorToDeleteAgain=mConnection.getCodePointBeforeCursor();
          if (codePointBeforeCursorToDeleteAgain != Constants.NOT_A_CODE) {
            final int lengthToDeleteAgain=Character.isSupplementaryCodePoint(codePointBeforeCursorToDeleteAgain) ? 2 : 1;
            mConnection.deleteSurroundingText(lengthToDeleteAgain,0);
            if (ProductionFlag.USES_DEVELOPMENT_ONLY_DIAGNOSTICS) {
              ResearchLogger.latinIME_handleBackspace(lengthToDeleteAgain,true);
            }
          }
        }
      }
    }
    if (settingsValues.isSuggestionStripVisible() && settingsValues.mSpacingAndPunctuations.mCurrentLanguageHasSpaces && !mConnection.isCursorFollowedByWordCharacter(settingsValues.mSpacingAndPunctuations)) {
      restartSuggestionsOnWordTouchedByCursor(settingsValues,true);
    }
    keyboardSwitcher.updateShiftState();
  }
}

Fixed version (ground truth):
/** 
 * Handle a press on the backspace key.
 * @param settingsValues The current settings values.
 * @param spaceState The space state at start of this batch edit.
 */
private void handleBackspace(final SettingsValues settingsValues,final int spaceState,final LatinIME.UIHandler handler,final KeyboardSwitcher keyboardSwitcher){
  mSpaceState=SpaceState.NONE;
  final int deleteCountAtStart=mDeleteCount;
  mDeleteCount++;
  handler.postUpdateShiftState();
  if (mWordComposer.isCursorFrontOrMiddleOfComposingWord()) {
    resetEntireInputState(settingsValues,mConnection.getExpectedSelectionStart(),mConnection.getExpectedSelectionEnd(),true);
  }
  if (mWordComposer.isComposingWord()) {
    if (mWordComposer.isBatchMode()) {
      if (ProductionFlag.USES_DEVELOPMENT_ONLY_DIAGNOSTICS) {
        final String word=mWordComposer.getTypedWord();
        ResearchLogger.latinIME_handleBackspace_batch(word,1);
      }
      final String rejectedSuggestion=mWordComposer.getTypedWord();
      mWordComposer.reset();
      mWordComposer.setRejectedBatchModeSuggestion(rejectedSuggestion);
    }
 else {
      mWordComposer.deleteLast();
    }
    mConnection.setComposingText(getTextWithUnderline(mWordComposer.getTypedWord()),1);
    handler.postUpdateSuggestionStrip();
    if (!mWordComposer.isComposingWord()) {
      keyboardSwitcher.updateShiftState();
    }
  }
 else {
    if (mLastComposedWord.canRevertCommit()) {
      if (settingsValues.mIsInternal) {
        LatinImeLoggerUtils.onAutoCorrectionCancellation();
      }
      revertCommit(settingsValues,handler);
      return;
    }
    if (mEnteredText != null && mConnection.sameAsTextBeforeCursor(mEnteredText)) {
      mConnection.deleteSurroundingText(mEnteredText.length(),0);
      if (ProductionFlag.USES_DEVELOPMENT_ONLY_DIAGNOSTICS) {
        ResearchLogger.latinIME_handleBackspace_cancelTextInput(mEnteredText);
      }
      mEnteredText=null;
      return;
    }
    if (SpaceState.DOUBLE == spaceState) {
      handler.cancelDoubleSpacePeriodTimer();
      if (mConnection.revertDoubleSpacePeriod()) {
        return;
      }
    }
 else     if (SpaceState.SWAP_PUNCTUATION == spaceState) {
      if (mConnection.revertSwapPunctuation()) {
        return;
      }
    }
    if (mConnection.hasSelection()) {
      final int numCharsDeleted=mConnection.getExpectedSelectionEnd() - mConnection.getExpectedSelectionStart();
      mConnection.setSelection(mConnection.getExpectedSelectionEnd(),mConnection.getExpectedSelectionEnd());
      mConnection.deleteSurroundingText(numCharsDeleted,0);
      if (ProductionFlag.USES_DEVELOPMENT_ONLY_DIAGNOSTICS) {
        ResearchLogger.latinIME_handleBackspace(numCharsDeleted,false);
      }
    }
 else {
      if (Constants.NOT_A_CURSOR_POSITION == mConnection.getExpectedSelectionEnd()) {
        Log.e(TAG,"String_Node_Str");
      }
      if (settingsValues.isBeforeJellyBean() || settingsValues.mInputAttributes.isTypeNull()) {
        sendDownUpKeyEvent(KeyEvent.KEYCODE_DEL);
        if (mDeleteCount > Constants.DELETE_ACCELERATE_AT) {
          sendDownUpKeyEvent(KeyEvent.KEYCODE_DEL);
        }
      }
 else {
        final int codePointBeforeCursor=mConnection.getCodePointBeforeCursor();
        if (codePointBeforeCursor == Constants.NOT_A_CODE) {
          mConnection.deleteSurroundingText(1,0);
          return;
        }
        final int lengthToDelete=Character.isSupplementaryCodePoint(codePointBeforeCursor) ? 2 : 1;
        mConnection.deleteSurroundingText(lengthToDelete,0);
        if (ProductionFlag.USES_DEVELOPMENT_ONLY_DIAGNOSTICS) {
          ResearchLogger.latinIME_handleBackspace(lengthToDelete,true);
        }
        if (mDeleteCount > Constants.DELETE_ACCELERATE_AT) {
          final int codePointBeforeCursorToDeleteAgain=mConnection.getCodePointBeforeCursor();
          if (codePointBeforeCursorToDeleteAgain != Constants.NOT_A_CODE) {
            final int lengthToDeleteAgain=Character.isSupplementaryCodePoint(codePointBeforeCursorToDeleteAgain) ? 2 : 1;
            mConnection.deleteSurroundingText(lengthToDeleteAgain,0);
            if (ProductionFlag.USES_DEVELOPMENT_ONLY_DIAGNOSTICS) {
              ResearchLogger.latinIME_handleBackspace(lengthToDeleteAgain,true);
            }
          }
        }
      }
    }
    if (settingsValues.isSuggestionStripVisible() && settingsValues.mSpacingAndPunctuations.mCurrentLanguageHasSpaces && !mConnection.isCursorFollowedByWordCharacter(settingsValues.mSpacingAndPunctuations)) {
      restartSuggestionsOnWordTouchedByCursor(settingsValues,true);
    }
    keyboardSwitcher.updateShiftState();
  }
}