add MaxWordsModified constraint, misc fixes and tweaks, linting

CONTRIBUTING.md

@@ -118,7 +118,7 @@ Follow these steps to start contributing:
    ```bash
    $ cd TextAttack
    $ pip install -e . ".[dev]"
-   $ pip install black isort pytest pytest-xdist
+   $ pip install black docformatter isort pytest pytest-xdist
    ```
 
    This will install `textattack` in editable mode and install `black` and 

docs/conf.py

@@ -21,7 +21,7 @@
 author = "UVA QData Lab"
 
 # The full version, including alpha/beta/rc tags
-release = "0.3.4"
+release = "0.3.5"
 
 # Set master doc to `index.rst`.
 master_doc = "index"

tests/test_attacked_text.py

@@ -61,7 +61,7 @@ def test_window_around_index(self, attacked_text):
 
     def test_big_window_around_index(self, attacked_text):
         assert (
-            attacked_text.text_window_around_index(0, 10 ** 5) + "."
+            attacked_text.text_window_around_index(0, 10**5) + "."
         ) == attacked_text.text
 
     def test_window_around_index_start(self, attacked_text):

tests/test_word_embedding.py

@@ -10,7 +10,7 @@ def test_embedding_paragramcf():
     word_embedding = WordEmbedding.counterfitted_GLOVE_embedding()
     assert pytest.approx(word_embedding[0][0]) == -0.022007
     assert pytest.approx(word_embedding["fawn"][0]) == -0.022007
-    assert word_embedding[10 ** 9] is None
+    assert word_embedding[10**9] is None
 
 
 def test_embedding_gensim():
@@ -37,7 +37,7 @@ def test_embedding_gensim():
     word_embedding = GensimWordEmbedding(keyed_vectors)
     assert pytest.approx(word_embedding[0][0]) == 1
     assert pytest.approx(word_embedding["bye-bye"][0]) == -1 / np.sqrt(2)
-    assert word_embedding[10 ** 9] is None
+    assert word_embedding[10**9] is None
 
     # test query functionality
     assert pytest.approx(word_embedding.get_cos_sim(1, 3)) == 0

textattack/attack.py

@@ -81,8 +81,8 @@ def __init__(
         constraints: List[Union[Constraint, PreTransformationConstraint]],
         transformation: Transformation,
         search_method: SearchMethod,
-        transformation_cache_size=2 ** 15,
-        constraint_cache_size=2 ** 15,
+        transformation_cache_size=2**15,
+        constraint_cache_size=2**15,
     ):
         """Initialize an attack object.
 
@@ -371,22 +371,23 @@ def _attack(self, initial_result):
         final_result = self.search_method(initial_result)
         self.clear_cache()
         if final_result.goal_status == GoalFunctionResultStatus.SUCCEEDED:
-            return SuccessfulAttackResult(
+            result = SuccessfulAttackResult(
                 initial_result,
                 final_result,
             )
         elif final_result.goal_status == GoalFunctionResultStatus.SEARCHING:
-            return FailedAttackResult(
+            result = FailedAttackResult(
                 initial_result,
                 final_result,
             )
         elif final_result.goal_status == GoalFunctionResultStatus.MAXIMIZING:
-            return MaximizedAttackResult(
+            result = MaximizedAttackResult(
                 initial_result,
                 final_result,
             )
         else:
             raise ValueError(f"Unrecognized goal status {final_result.goal_status}")
+        return result
 
     def attack(self, example, ground_truth_output):
         """Attack a single example.

textattack/attack_args.py

@@ -478,8 +478,8 @@ class _CommandLineAttackArgs:
     interactive: bool = False
     parallel: bool = False
     model_batch_size: int = 32
-    model_cache_size: int = 2 ** 18
-    constraint_cache_size: int = 2 ** 18
+    model_cache_size: int = 2**18
+    constraint_cache_size: int = 2**18
 
     @classmethod
     def _add_parser_args(cls, parser):

textattack/constraints/grammaticality/cola.py

@@ -43,7 +43,7 @@ def __init__(
 
         self.max_diff = max_diff
         self.model_name = model_name
-        self._reference_score_cache = lru.LRU(2 ** 10)
+        self._reference_score_cache = lru.LRU(2**10)
         model = AutoModelForSequenceClassification.from_pretrained(model_name)
         tokenizer = AutoTokenizer.from_pretrained(model_name)
         self.model = HuggingFaceModelWrapper(model, tokenizer)

textattack/constraints/grammaticality/language_models/google_language_model/alzantot_goog_lm.py

@@ -49,7 +49,7 @@ def __init__(self):
                 self.sess, self.graph, self.PBTXT_PATH, self.CKPT_PATH
             )
 
-        self.lm_cache = lru.LRU(2 ** 18)
+        self.lm_cache = lru.LRU(2**18)
 
     def clear_cache(self):
         self.lm_cache.clear()

textattack/constraints/grammaticality/part_of_speech.py

@@ -56,7 +56,7 @@ def __init__(
         self.language_nltk = language_nltk
         self.language_stanza = language_stanza
 
-        self._pos_tag_cache = lru.LRU(2 ** 14)
+        self._pos_tag_cache = lru.LRU(2**14)
         if tagger_type == "flair":
             if tagset == "universal":
                 self._flair_pos_tagger = SequenceTagger.load("upos-fast")
@@ -93,7 +93,8 @@ def _get_pos(self, before_ctx, word, after_ctx):
 
             if self.tagger_type == "flair":
                 context_key_sentence = Sentence(
-                    context_key, use_tokenizer=textattack.shared.utils.words_from_text
+                    context_key,
+                    use_tokenizer=textattack.shared.utils.TextAttackFlairTokenizer(),
                 )
                 self._flair_pos_tagger.predict(context_key_sentence)
                 word_list, pos_list = textattack.shared.utils.zip_flair_result(

textattack/constraints/pre_transformation/__init__.py

@@ -9,5 +9,6 @@
 from .repeat_modification import RepeatModification
 from .input_column_modification import InputColumnModification
 from .max_word_index_modification import MaxWordIndexModification
+from .max_num_words_modified import MaxNumWordsModified
 from .min_word_length import MinWordLength
 from .max_modification_rate import MaxModificationRate

textattack/constraints/pre_transformation/max_num_words_modified.py

@@ -0,0 +1,25 @@
+"""
+
+Max Modification Rate
+-----------------------------
+
+"""
+
+from textattack.constraints import PreTransformationConstraint
+
+
+class MaxNumWordsModified(PreTransformationConstraint):
+    def __init__(self, max_num_words: int):
+        self.max_num_words = max_num_words
+
+    def _get_modifiable_indices(self, current_text):
+        """Returns the word indices in current_text which are able to be
+        modified."""
+
+        if len(current_text.attack_attrs["modified_indices"]) >= self.max_num_words:
+            return set()
+        else:
+            return set(range(len(current_text.words)))
+
+    def extra_repr_keys(self):
+        return ["max_num_words"]

textattack/constraints/semantics/sentence_encoders/thought_vector.py

@@ -32,7 +32,7 @@ def __init__(self, embedding=None, **kwargs):
     def clear_cache(self):
         self._get_thought_vector.cache_clear()
 
-    @functools.lru_cache(maxsize=2 ** 10)
+    @functools.lru_cache(maxsize=2**10)
     def _get_thought_vector(self, text):
         """Sums the embeddings of all the words in ``text`` into a "thought
         vector"."""

textattack/constraints/semantics/sentence_encoders/universal_sentence_encoder/universal_sentence_encoder.py

@@ -19,7 +19,7 @@ def __init__(self, threshold=0.8, large=False, metric="angular", **kwargs):
         if large:
             tfhub_url = "https://tfhub.dev/google/universal-sentence-encoder-large/5"
         else:
-            tfhub_url = "https://tfhub.dev/google/universal-sentence-encoder/4"
+            tfhub_url = "https://tfhub.dev/google/universal-sentence-encoder/3"
 
         self._tfhub_url = tfhub_url
         # Lazily load the model
@@ -28,7 +28,12 @@ def __init__(self, threshold=0.8, large=False, metric="angular", **kwargs):
     def encode(self, sentences):
         if not self.model:
             self.model = hub.load(self._tfhub_url)
-        return self.model(sentences).numpy()
+        encoding = self.model(sentences)
+
+        if isinstance(encoding, dict):
+            encoding = encoding["outputs"]
+
+        return encoding.numpy()
 
     def __getstate__(self):
         state = self.__dict__.copy()

textattack/goal_functions/goal_function.py

@@ -40,7 +40,7 @@ def __init__(
         use_cache=True,
         query_budget=float("inf"),
         model_batch_size=32,
-        model_cache_size=2 ** 20,
+        model_cache_size=2**20,
     ):
         validators.validate_model_goal_function_compatibility(
             self.__class__, model_wrapper.model.__class__

textattack/goal_functions/text/minimize_bleu.py

@@ -59,7 +59,7 @@ def extra_repr_keys(self):
             return ["maximizable", "target_bleu"]
 
 
-@functools.lru_cache(maxsize=2 ** 12)
+@functools.lru_cache(maxsize=2**12)
 def get_bleu(a, b):
     ref = a.words
     hyp = b.words

textattack/goal_functions/text/non_overlapping_output.py

@@ -38,12 +38,12 @@ def _get_score(self, model_output, _):
             return num_words_diff / len(get_words_cached(self.ground_truth_output))
 
 
-@functools.lru_cache(maxsize=2 ** 12)
+@functools.lru_cache(maxsize=2**12)
 def get_words_cached(s):
     return np.array(words_from_text(s))
 
 
-@functools.lru_cache(maxsize=2 ** 12)
+@functools.lru_cache(maxsize=2**12)
 def word_difference_score(s1, s2):
     """Returns the number of words that are non-overlapping between s1 and
     s2."""

textattack/metrics/attack_metrics/words_perturbed.py

@@ -31,7 +31,7 @@ def calculate(self, results):
         self.total_attacks = len(self.results)
         self.all_num_words = np.zeros(len(self.results))
         self.perturbed_word_percentages = np.zeros(len(self.results))
-        self.num_words_changed_until_success = np.zeros(2 ** 16)
+        self.num_words_changed_until_success = np.zeros(2**16)
         self.max_words_changed = 0
 
         for i, result in enumerate(self.results):

textattack/search_methods/greedy_word_swap_wir.py

@@ -31,8 +31,9 @@ class GreedyWordSwapWIR(SearchMethod):
         model_wrapper: model wrapper used for gradient-based ranking
     """
 
-    def __init__(self, wir_method="unk"):
+    def __init__(self, wir_method="unk", unk_token="[UNK]"):
         self.wir_method = wir_method
+        self.unk_token = unk_token
 
     def _get_index_order(self, initial_text):
         """Returns word indices of ``initial_text`` in descending order of
@@ -41,15 +42,17 @@ def _get_index_order(self, initial_text):
 
         if self.wir_method == "unk":
             leave_one_texts = [
-                initial_text.replace_word_at_index(i, "[UNK]") for i in range(len_text)
+                initial_text.replace_word_at_index(i, self.unk_token)
+                for i in range(len_text)
             ]
             leave_one_results, search_over = self.get_goal_results(leave_one_texts)
             index_scores = np.array([result.score for result in leave_one_results])
 
         elif self.wir_method == "weighted-saliency":
             # first, compute word saliency
             leave_one_texts = [
-                initial_text.replace_word_at_index(i, "[UNK]") for i in range(len_text)
+                initial_text.replace_word_at_index(i, self.unk_token)
+                for i in range(len_text)
             ]
             leave_one_results, search_over = self.get_goal_results(leave_one_texts)
             saliency_scores = np.array([result.score for result in leave_one_results])

textattack/shared/attacked_text.py

@@ -138,7 +138,8 @@ def pos_of_word_index(self, desired_word_idx):
         """
         if not self._pos_tags:
             sentence = Sentence(
-                self.text, use_tokenizer=textattack.shared.utils.words_from_text
+                self.text,
+                use_tokenizer=textattack.shared.utils.TextAttackFlairTokenizer(),
             )
             textattack.shared.utils.flair_tag(sentence)
             self._pos_tags = sentence
@@ -168,7 +169,8 @@ def ner_of_word_index(self, desired_word_idx, model_name="ner"):
         """
         if not self._ner_tags:
             sentence = Sentence(
-                self.text, use_tokenizer=textattack.shared.utils.words_from_text
+                self.text,
+                use_tokenizer=textattack.shared.utils.TextAttackFlairTokenizer(),
             )
             textattack.shared.utils.flair_tag(sentence, model_name)
             self._ner_tags = sentence
@@ -467,6 +469,10 @@ def generate_new_attacked_text(self, new_words):
             # Add substitute word(s) to new sentence.
             perturbed_text += adv_word_seq
         perturbed_text += original_text  # Add all of the ending punctuation.
+
+        # Add pointer to self so chain of replacements can be reconstructed.
+        new_attack_attrs["prev_attacked_text"] = self
+
         # Reform perturbed_text into an OrderedDict.
         perturbed_input_texts = perturbed_text.split(AttackedText.SPLIT_TOKEN)
         perturbed_input = OrderedDict(

textattack/shared/utils/misc.py

@@ -7,7 +7,9 @@
 
 import textattack
 
-device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
+device = os.environ.get(
+    "TA_DEVICE", torch.device("cuda" if torch.cuda.is_available() else "cpu")
+)
 
 
 def html_style_from_dict(style_dict):

textattack/shared/utils/strings.py

@@ -1,5 +1,6 @@
 import string
 
+import flair
 import jieba
 import pycld2 as cld2
 
@@ -106,6 +107,11 @@ def words_from_text(s, words_to_ignore=[]):
     return words
 
 
+class TextAttackFlairTokenizer(flair.data.Tokenizer):
+    def tokenize(self, text: str):
+        return words_from_text(text)
+
+
 def default_class_repr(self):
     if hasattr(self, "extra_repr_keys"):
         extra_params = []