Make the sacremoses dependency optional (huggingface#17049)

* Make sacremoses optional

* Pickle

setup.py

@@ -288,6 +288,7 @@ def run(self):
         "nltk",
         "GitPython",
         "hf-doc-builder",
+        'sacremoses'
     )
     + extras["retrieval"]
     + extras["modelcreation"]
@@ -365,7 +366,6 @@ def run(self):
     "protobuf",
     "regex",
     "requests",
-    "sacremoses",
     "sentencepiece",
     "torch",
     "tokenizers",
@@ -383,7 +383,6 @@ def run(self):
     deps["pyyaml"],  # used for the model cards metadata
     deps["regex"],  # for OpenAI GPT
     deps["requests"],  # for downloading models over HTTPS
-    deps["sacremoses"],  # for XLM
     deps["tokenizers"],
     deps["tqdm"],  # progress bars in model download and training scripts
 ]

src/transformers/dependency_versions_check.py

@@ -23,7 +23,7 @@
 # order specific notes:
 # - tqdm must be checked before tokenizers
 
-pkgs_to_check_at_runtime = "python tqdm regex sacremoses requests packaging filelock numpy tokenizers".split()
+pkgs_to_check_at_runtime = "python tqdm regex requests packaging filelock numpy tokenizers".split()
 if sys.version_info < (3, 7):
     pkgs_to_check_at_runtime.append("dataclasses")
 if sys.version_info < (3, 8):

src/transformers/models/fsmt/tokenization_fsmt.py

@@ -21,8 +21,6 @@
 import unicodedata
 from typing import Dict, List, Optional, Tuple
 
-import sacremoses as sm
-
 from ...tokenization_utils import PreTrainedTokenizer
 from ...utils import logging
 
@@ -212,6 +210,16 @@ def __init__(
             **kwargs,
         )
 
+        try:
+            import sacremoses
+        except ImportError:
+            raise ImportError(
+                "You need to install sacremoses to use XLMTokenizer. "
+                "See https://pypi.org/project/sacremoses/ for installation."
+            )
+
+        self.sm = sacremoses
+
         self.src_vocab_file = src_vocab_file
         self.tgt_vocab_file = tgt_vocab_file
         self.merges_file = merges_file
@@ -254,21 +262,21 @@ def vocab_size(self) -> int:
 
     def moses_punct_norm(self, text, lang):
         if lang not in self.cache_moses_punct_normalizer:
-            punct_normalizer = sm.MosesPunctNormalizer(lang=lang)
+            punct_normalizer = self.sm.MosesPunctNormalizer(lang=lang)
             self.cache_moses_punct_normalizer[lang] = punct_normalizer
         return self.cache_moses_punct_normalizer[lang].normalize(text)
 
     def moses_tokenize(self, text, lang):
         if lang not in self.cache_moses_tokenizer:
-            moses_tokenizer = sm.MosesTokenizer(lang=lang)
+            moses_tokenizer = self.sm.MosesTokenizer(lang=lang)
             self.cache_moses_tokenizer[lang] = moses_tokenizer
         return self.cache_moses_tokenizer[lang].tokenize(
             text, aggressive_dash_splits=True, return_str=False, escape=True
         )
 
     def moses_detokenize(self, tokens, lang):
         if lang not in self.cache_moses_tokenizer:
-            moses_detokenizer = sm.MosesDetokenizer(lang=self.tgt_lang)
+            moses_detokenizer = self.sm.MosesDetokenizer(lang=self.tgt_lang)
             self.cache_moses_detokenizer[lang] = moses_detokenizer
         return self.cache_moses_detokenizer[lang].detokenize(tokens)
 
@@ -516,3 +524,21 @@ def save_vocabulary(self, save_directory: str, filename_prefix: Optional[str] =
                 index += 1
 
         return src_vocab_file, tgt_vocab_file, merges_file
+
+    def __getstate__(self):
+        state = self.__dict__.copy()
+        state["sm"] = None
+        return state
+
+    def __setstate__(self, d):
+        self.__dict__ = d
+
+        try:
+            import sacremoses
+        except ImportError:
+            raise ImportError(
+                "You need to install sacremoses to use XLMTokenizer. "
+                "See https://pypi.org/project/sacremoses/ for installation."
+            )
+
+        self.sm = sacremoses

src/transformers/models/xlm/tokenization_xlm.py

@@ -22,8 +22,6 @@
 import unicodedata
 from typing import List, Optional, Tuple
 
-import sacremoses as sm
-
 from ...tokenization_utils import PreTrainedTokenizer
 from ...utils import logging
 
@@ -629,6 +627,16 @@ def __init__(
             **kwargs,
         )
 
+        try:
+            import sacremoses
+        except ImportError:
+            raise ImportError(
+                "You need to install sacremoses to use XLMTokenizer. "
+                "See https://pypi.org/project/sacremoses/ for installation."
+            )
+
+        self.sm = sacremoses
+
         # cache of sm.MosesPunctNormalizer instance
         self.cache_moses_punct_normalizer = dict()
         # cache of sm.MosesTokenizer instance
@@ -659,15 +667,15 @@ def do_lower_case(self):
 
     def moses_punct_norm(self, text, lang):
         if lang not in self.cache_moses_punct_normalizer:
-            punct_normalizer = sm.MosesPunctNormalizer(lang=lang)
+            punct_normalizer = self.sm.MosesPunctNormalizer(lang=lang)
             self.cache_moses_punct_normalizer[lang] = punct_normalizer
         else:
             punct_normalizer = self.cache_moses_punct_normalizer[lang]
         return punct_normalizer.normalize(text)
 
     def moses_tokenize(self, text, lang):
         if lang not in self.cache_moses_tokenizer:
-            moses_tokenizer = sm.MosesTokenizer(lang=lang)
+            moses_tokenizer = self.sm.MosesTokenizer(lang=lang)
             self.cache_moses_tokenizer[lang] = moses_tokenizer
         else:
             moses_tokenizer = self.cache_moses_tokenizer[lang]
@@ -970,3 +978,21 @@ def save_vocabulary(self, save_directory: str, filename_prefix: Optional[str] =
                 index += 1
 
         return vocab_file, merge_file
+
+    def __getstate__(self):
+        state = self.__dict__.copy()
+        state["sm"] = None
+        return state
+
+    def __setstate__(self, d):
+        self.__dict__ = d
+
+        try:
+            import sacremoses
+        except ImportError:
+            raise ImportError(
+                "You need to install sacremoses to use XLMTokenizer. "
+                "See https://pypi.org/project/sacremoses/ for installation."
+            )
+
+        self.sm = sacremoses