[HUGE] Refactoring tokenizers backend - padding - truncation - pre-tokenized...

[HUGE] Refactoring tokenizers backend - padding - truncation - pre-tokenized pipeline - fast tokenizers - tests (#4510)

* Use tokenizers pre-tokenized pipeline

* failing pretrokenized test

* Fix is_pretokenized in python

* add pretokenized tests

* style and quality

* better tests for batched pretokenized inputs

* tokenizers clean up - new padding_strategy - split the files

* [HUGE] refactoring tokenizers - padding - truncation - tests

* style and quality

* bump up requied tokenizers version to 0.8.0-rc1

* switched padding/truncation API - simpler better backward compat

* updating tests for custom tokenizers

* style and quality - tests on pad

* fix QA pipeline

* fix backward compatibility for max_length only

* style and quality

* Various cleans up - add verbose

* fix tests

* update docstrings

* Fix tests

* Docs reformatted

* __call__ method documented
Co-authored-by: Thomas Wolf <thomwolf@users.noreply.github.com>
Co-authored-by: Lysandre <lysandre.debut@reseau.eseo.fr>

docs/source/main_classes/tokenizer.rst

@@ -17,12 +17,14 @@ The base classes ``PreTrainedTokenizer`` and ``PreTrainedTokenizerFast`` impleme
 ~~~~~~~~~~~~~~~~~~~~~~~~
 
 .. autoclass:: transformers.PreTrainedTokenizer
+    :special-members: __call__
     :members:
 
 ``PreTrainedTokenizerFast``
-~~~~~~~~~~~~~~~~~~~~~~~~
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 .. autoclass:: transformers.PreTrainedTokenizerFast
+    :special-members: __call__
     :members:
 
 ``BatchEncoding``

examples/summarization/utils.py

@@ -3,8 +3,6 @@ import os
 import torch
 from torch.utils.data import Dataset
 
-from transformers.tokenization_utils import trim_batch
-
 
 def encode_file(tokenizer, data_path, max_length, pad_to_max_length=True, return_tensors="pt"):
     examples = []
@@ -17,6 +15,17 @@ def encode_file(tokenizer, data_path, max_length, pad_to_max_length=True, return
     return examples
 
 
+def trim_batch(
+    input_ids, pad_token_id, attention_mask=None,
+):
+    """Remove columns that are populated exclusively by pad_token_id"""
+    keep_column_mask = input_ids.ne(pad_token_id).any(dim=0)
+    if attention_mask is None:
+        return input_ids[:, keep_column_mask]
+    else:
+        return (input_ids[:, keep_column_mask], attention_mask[:, keep_column_mask])
+
+
 class SummarizationDataset(Dataset):
     def __init__(
         self,

setup.py

@@ -108,7 +108,7 @@ setup(
     packages=find_packages("src"),
     install_requires=[
         "numpy",
-        "tokenizers == 0.7.0",
+        "tokenizers == 0.8.0-rc1",
         # dataclasses for Python versions that don't have it
         "dataclasses;python_version<'3.7'",
         # utilities from PyPA to e.g. compare versions

src/transformers/__init__.py

@@ -133,13 +133,16 @@ from .tokenization_reformer import ReformerTokenizer
 from .tokenization_roberta import RobertaTokenizer, RobertaTokenizerFast
 from .tokenization_t5 import T5Tokenizer
 from .tokenization_transfo_xl import TransfoXLCorpus, TransfoXLTokenizer, TransfoXLTokenizerFast
-from .tokenization_utils import (
+from .tokenization_utils import PreTrainedTokenizer
+from .tokenization_utils_base import (
     BatchEncoding,
-    PreTrainedTokenizer,
-    PreTrainedTokenizerFast,
+    CharSpan,
+    PreTrainedTokenizerBase,
     SpecialTokensMixin,
     TensorType,
+    TokenSpan,
 )
+from .tokenization_utils_fast import PreTrainedTokenizerFast
 from .tokenization_xlm import XLMTokenizer
 from .tokenization_xlm_roberta import XLMRobertaTokenizer
 from .tokenization_xlnet import SPIECE_UNDERLINE, XLNetTokenizer

src/transformers/modeling_tf_albert.py

@@ -1213,7 +1213,7 @@ class TFAlbertForMultipleChoice(TFAlbertPreTrainedModel, TFMultipleChoiceLoss):
         model = TFAlbertForMultipleChoice.from_pretrained('albert-base-v2')
         choices = ["Hello, my dog is cute", "Hello, my cat is amazing"]
 
-        input_ids = tf.constant([tokenizer.encode(s, add_special_tokens=True) for s in choices])[None, :] # Batch size 1, 2 choices
+        input_ids = tokenizer(choices, add_special_tokens=True, return_tensors='tf', truncation=True, padding=True)[None, :] # Batch size 1, 2 choices
         labels = tf.reshape(tf.constant(1), (-1, 1))
         outputs = model(input_ids, labels=labels)
 

src/transformers/tokenization_bert.py

@@ -23,7 +23,8 @@ from typing import List, Optional
 
 from tokenizers import BertWordPieceTokenizer
 
-from .tokenization_utils import PreTrainedTokenizer, PreTrainedTokenizerFast
+from .tokenization_utils import PreTrainedTokenizer
+from .tokenization_utils_fast import PreTrainedTokenizerFast
 
 
 logger = logging.getLogger(__name__)

src/transformers/tokenization_gpt2.py

@@ -23,7 +23,9 @@ from functools import lru_cache
 import regex as re
 from tokenizers import ByteLevelBPETokenizer
 
-from .tokenization_utils import PreTrainedTokenizer, PreTrainedTokenizerFast
+from .tokenization_utils import PreTrainedTokenizer
+from .tokenization_utils_base import BatchEncoding
+from .tokenization_utils_fast import PreTrainedTokenizerFast
 
 
 logger = logging.getLogger(__name__)
@@ -346,3 +348,24 @@ class GPT2TokenizerFast(PreTrainedTokenizerFast):
             unk_token=unk_token,
             **kwargs,
         )
+        self.add_prefix_space = add_prefix_space
+
+    def _batch_encode_plus(self, *args, **kwargs) -> BatchEncoding:
+
+        is_pretokenized = kwargs.get("is_pretokenized", False)
+        assert self.add_prefix_space or not is_pretokenized, (
+            "You need to instantiate GPT2TokenizerFast with add_prefix_space=False "
+            "to use it with pretokenized inputs."
+        )
+
+        return super()._batch_encode_plus(*args, **kwargs)
+
+    def _encode_plus(self, *args, **kwargs) -> BatchEncoding:
+
+        is_pretokenized = kwargs.get("is_pretokenized", False)
+        assert self.add_prefix_space or not is_pretokenized, (
+            "You need to instantiate GPT2TokenizerFast with add_prefix_space=False "
+            "to use it with pretokenized inputs."
+        )
+
+        return super()._encode_plus(*args, **kwargs)

src/transformers/tokenization_openai.py

@@ -23,7 +23,8 @@ import re
 from tokenizers import CharBPETokenizer
 
 from .tokenization_bert import BasicTokenizer
-from .tokenization_utils import PreTrainedTokenizer, PreTrainedTokenizerFast
+from .tokenization_utils import PreTrainedTokenizer
+from .tokenization_utils_fast import PreTrainedTokenizerFast
 
 
 logger = logging.getLogger(__name__)

src/transformers/tokenization_transfo_xl.py

@@ -35,7 +35,8 @@ from tokenizers.pre_tokenizers import CharDelimiterSplit, WhitespaceSplit
 from tokenizers.processors import BertProcessing
 
 from .file_utils import cached_path, is_torch_available
-from .tokenization_utils import PreTrainedTokenizer, PreTrainedTokenizerFast
+from .tokenization_utils import PreTrainedTokenizer
+from .tokenization_utils_fast import PreTrainedTokenizerFast
 
 
 if is_torch_available():

templates/adding_a_new_model/tests/test_tokenization_xxx.py

@@ -51,7 +51,7 @@ class XxxTokenizationTest(TokenizerTesterMixin, unittest.TestCase):
     def get_tokenizer(self, **kwargs):
         return XxxTokenizer.from_pretrained(self.tmpdirname, **kwargs)
 
-    def get_input_output_texts(self):
+    def get_input_output_texts(self, tokenizer):
         input_text = "UNwant\u00E9d,running"
         output_text = "unwanted, running"
         return input_text, output_text

tests/test_tokenization_albert.py

@@ -36,7 +36,7 @@ class AlbertTokenizationTest(TokenizerTesterMixin, unittest.TestCase):
         tokenizer = AlbertTokenizer(SAMPLE_VOCAB)
         tokenizer.save_pretrained(self.tmpdirname)
 
-    def get_input_output_texts(self):
+    def get_input_output_texts(self, tokenizer):
         input_text = "this is a test"
         output_text = "this is a test"
         return input_text, output_text

tests/test_tokenization_bert.py

@@ -44,6 +44,8 @@ class BertTokenizationTest(TokenizerTesterMixin, unittest.TestCase):
             "[UNK]",
             "[CLS]",
             "[SEP]",
+            "[PAD]",
+            "[MASK]",
             "want",
             "##want",
             "##ed",
@@ -62,7 +64,7 @@ class BertTokenizationTest(TokenizerTesterMixin, unittest.TestCase):
     def get_rust_tokenizer(self, **kwargs):
         return BertTokenizerFast.from_pretrained(self.tmpdirname, **kwargs)
 
-    def get_input_output_texts(self):
+    def get_input_output_texts(self, tokenizer):
         input_text = "UNwant\u00E9d,running"
         output_text = "unwanted, running"
         return input_text, output_text
@@ -72,7 +74,7 @@ class BertTokenizationTest(TokenizerTesterMixin, unittest.TestCase):
 
         tokens = tokenizer.tokenize("UNwant\u00E9d,running")
         self.assertListEqual(tokens, ["un", "##want", "##ed", ",", "runn", "##ing"])
-        self.assertListEqual(tokenizer.convert_tokens_to_ids(tokens), [7, 4, 5, 10, 8, 9])
+        self.assertListEqual(tokenizer.convert_tokens_to_ids(tokens), [9, 6, 7, 12, 10, 11])
 
     def test_rust_and_python_full_tokenizers(self):
         if not self.test_rust_tokenizer:
@@ -96,6 +98,25 @@ class BertTokenizationTest(TokenizerTesterMixin, unittest.TestCase):
         rust_ids = rust_tokenizer.encode(sequence)
         self.assertListEqual(ids, rust_ids)
 
+        # With lower casing
+        tokenizer = self.get_tokenizer(do_lower_case=True)
+        rust_tokenizer = self.get_rust_tokenizer(do_lower_case=True)
+
+        sequence = "UNwant\u00E9d,running"
+
+        tokens = tokenizer.tokenize(sequence)
+        rust_tokens = rust_tokenizer.tokenize(sequence)
+        self.assertListEqual(tokens, rust_tokens)
+
+        ids = tokenizer.encode(sequence, add_special_tokens=False)
+        rust_ids = rust_tokenizer.encode(sequence, add_special_tokens=False)
+        self.assertListEqual(ids, rust_ids)
+
+        rust_tokenizer = self.get_rust_tokenizer()
+        ids = tokenizer.encode(sequence)
+        rust_ids = rust_tokenizer.encode(sequence)
+        self.assertListEqual(ids, rust_ids)
+
     def test_chinese(self):
         tokenizer = BasicTokenizer()
 

tests/test_tokenization_ctrl.py

@@ -46,7 +46,7 @@ class CTRLTokenizationTest(TokenizerTesterMixin, unittest.TestCase):
         kwargs.update(self.special_tokens_map)
         return CTRLTokenizer.from_pretrained(self.tmpdirname, **kwargs)
 
-    def get_input_output_texts(self):
+    def get_input_output_texts(self, tokenizer):
         input_text = "adapt react readapt apt"
         output_text = "adapt react readapt apt"
         return input_text, output_text