Fix bug involving temporary filepaths when loading a Tokenizer of a T…

…okenTextEncoder.

Because the data directory is marked as "incomplete" while the dataset is being built, and later renamed, absolute filepaths written while the dataset is being built are wrong. This change eliminates the absolute filepaths and instead assumes a constant relative structure between the metadata files.

PiperOrigin-RevId: 258279826

tensorflow_datasets/core/features/text/text_encoder.py

@@ -330,16 +330,16 @@ def save_to_file(self, filename_prefix):
     }
     if self._user_defined_tokenizer is not None:
       self._tokenizer.save_to_file(filename)
-      kwargs["tokenizer_file_prefix"] = filename
+      kwargs["has_tokenizer"] = True
     self._write_lines_to_file(filename, self._vocab_list, kwargs)
 
   @classmethod
   def load_from_file(cls, filename_prefix):
     filename = cls._filename(filename_prefix)
     vocab_lines, kwargs = cls._read_lines_from_file(filename)
-    tokenizer_file = kwargs.pop("tokenizer_file_prefix", None)
-    if tokenizer_file:
-      kwargs["tokenizer"] = Tokenizer.load_from_file(tokenizer_file)
+    has_tokenizer = kwargs.pop("has_tokenizer", False)
+    if has_tokenizer:
+      kwargs["tokenizer"] = Tokenizer.load_from_file(filename)
     return cls(vocab_list=vocab_lines, **kwargs)