Generate: Fix GIT batched captioning (#21738)

tests/models/git/test_modeling_git.py

@@ -340,6 +340,24 @@ class GitModelTester:
 
         self.parent.assertEqual(generated_ids.shape, (self.batch_size * 2, 20))
 
+    def _test_batched_generate_captioning(self, config, input_ids, input_mask, pixel_values):
+        model = GitForCausalLM(config=config)
+        model.to(torch_device)
+        model.eval()
+
+        # generate
+        generated_ids = model.generate(
+            input_ids=None,  # captioning -> no input_ids
+            attention_mask=None,
+            pixel_values=pixel_values,
+            do_sample=False,
+            max_length=20,
+            num_beams=2,
+            num_return_sequences=2,
+        )
+
+        self.parent.assertEqual(generated_ids.shape, (self.batch_size * 2, 20))
+
     def prepare_config_and_inputs_for_common(self):
         config_and_inputs = self.prepare_config_and_inputs()
 
@@ -398,6 +416,10 @@ class GitModelTest(ModelTesterMixin, GenerationTesterMixin, unittest.TestCase):
         config_and_inputs = self.model_tester.prepare_config_and_inputs()
         self.model_tester._test_beam_search_generate(*config_and_inputs)
 
+    def test_batched_generate_captioning(self):
+        config_and_inputs = self.model_tester.prepare_config_and_inputs()
+        self.model_tester._test_batched_generate_captioning(*config_and_inputs)
+
     def test_model_various_embeddings(self):
         config_and_inputs = self.model_tester.prepare_config_and_inputs()
         for type in ["absolute", "relative_key", "relative_key_query"]: