[Bart] better error message (#14854)

src/transformers/models/bart/modeling_bart.py

@@ -1171,6 +1171,13 @@ class BartModel(BartPretrainedModel):
         # different to other models, Bart automatically creates decoder_input_ids from
         # input_ids if no decoder_input_ids are provided
         if decoder_input_ids is None and decoder_inputs_embeds is None:
+            if input_ids is None:
+                raise ValueError(
+                    "If no `decoder_input_ids` or `decoder_inputs_embeds` are "
+                    "passed, `input_ids` cannot be `None`. Please pass either "
+                    "`input_ids` or `decoder_input_ids` or `decoder_inputs_embeds`."
+                )
+
             decoder_input_ids = shift_tokens_right(
                 input_ids, self.config.pad_token_id, self.config.decoder_start_token_id
             )

src/transformers/models/bigbird_pegasus/modeling_bigbird_pegasus.py

@@ -2369,6 +2369,13 @@ class BigBirdPegasusModel(BigBirdPegasusPreTrainedModel):
         # different to other models, BigBirdPegasus automatically creates decoder_input_ids from
         # input_ids if no decoder_input_ids are provided
         if decoder_input_ids is None and decoder_inputs_embeds is None:
+            if input_ids is None:
+                raise ValueError(
+                    "If no `decoder_input_ids` or `decoder_inputs_embeds` are "
+                    "passed, `input_ids` cannot be `None`. Please pass either "
+                    "`input_ids` or `decoder_input_ids` or `decoder_inputs_embeds`."
+                )
+
             decoder_input_ids = shift_tokens_right(
                 input_ids, self.config.pad_token_id, self.config.decoder_start_token_id
             )