Fix tokenizer UnboundLocalError when padding is set to PaddingStrategy.MAX_LENGTH (#7610)

* Fix UnboundLocalError when PaddingStrategy is MAX_LENGTH

* Fix UnboundLocalError for TruncationStrategy

src/transformers/tokenization_utils_base.py

@@ -1781,6 +1781,8 @@ class PreTrainedTokenizerBase(SpecialTokensMixin):
                 padding_strategy = PaddingStrategy.LONGEST  # Default to pad to the longest sequence in the batch
             elif not isinstance(padding, PaddingStrategy):
                 padding_strategy = PaddingStrategy(padding)
+            elif isinstance(padding, PaddingStrategy):
+                padding_strategy = padding
         else:
             padding_strategy = PaddingStrategy.DO_NOT_PAD
 
@@ -1806,6 +1808,8 @@ class PreTrainedTokenizerBase(SpecialTokensMixin):
                 )  # Default to truncate the longest sequences in pairs of inputs
             elif not isinstance(truncation, TruncationStrategy):
                 truncation_strategy = TruncationStrategy(truncation)
+            elif isinstance(truncation, TruncationStrategy):
+                truncation_strategy = truncation
         else:
             truncation_strategy = TruncationStrategy.DO_NOT_TRUNCATE