LLaVaNeXT: pad on right if training (#32134)

* pad on right if training

* docs

* add tests

tests/models/llava_next/test_modeling_llava_next.py

@@ -123,7 +123,7 @@ class LlavaNextVisionText2TextModelTester:
         self.batch_size = 3
         self.num_channels = 3
         self.image_size = 30
-        self.encoder_seq_length = 341
+        self.encoder_seq_length = 342
         self.image_grid_pinpoints = [[32, 32]]
 
     def get_config(self):
@@ -156,9 +156,7 @@ class LlavaNextVisionText2TextModelTester:
         config_and_inputs = self.prepare_config_and_inputs()
         config, pixel_values = config_and_inputs
         input_ids = ids_tensor([self.batch_size, self.seq_length], config.text_config.vocab_size - 2) + 2
-        # make attention mask left-padded to avoid issues with "model has no attribute padding_side"
         attention_mask = torch.ones(input_ids.shape, dtype=torch.long).to(torch_device)
-        attention_mask[:, :1] = 0
         # we are giving 3 images let's make sure we pass in 3 image tokens
         input_ids[:, 1] = config.image_token_index
         labels = torch.zeros((self.batch_size, self.seq_length), dtype=torch.long, device=torch_device)
@@ -473,3 +471,37 @@ class LlavaNextForConditionalGenerationIntegrationTest(unittest.TestCase):
             self.processor.decode(output_batched[0], skip_special_tokens=True),
             self.processor.decode(output_single[0], skip_special_tokens=True),
         )
+
+    @slow
+    @require_bitsandbytes
+    def test_padding_side_when_merging_inputs(self):
+        model = LlavaNextForConditionalGeneration.from_pretrained(
+            "llava-hf/llava-v1.6-mistral-7b-hf",
+            load_in_4bit=True,
+        )
+
+        url = "http://images.cocodataset.org/val2017/000000039769.jpg"
+        lowres_url = "https://4.img-dpreview.com/files/p/TS560x560~forums/56876524/03975b28741443319e9a94615e35667e"
+        cats_image = Image.open(requests.get(url, stream=True).raw)
+        lowres_img = Image.open(requests.get(lowres_url, stream=True).raw)
+
+        inputs_batched = self.processor(
+            [self.prompt, self.prompt], images=[lowres_img, cats_image], return_tensors="pt", padding=True
+        ).to(torch_device)
+
+        # model is in eval mode by default so we should get pad on the left side
+        # we can check the first hidden-states (aka inputs embeds)
+        # the first element was lo-res image and we expect the first 1414 tokens to be all pads
+        output_eval = model(**inputs_batched, output_hidden_states=True)
+        self.assertTrue((output_eval.hidden_states[0][0, :1414, ...] == 0).all().item())
+
+        # otherwise padding is on the right side, so it's last 1414 tokens
+        self.processor.padding_side = "right"
+        inputs_batched = self.processor(
+            [self.prompt, self.prompt], images=[lowres_img, cats_image], return_tensors="pt", padding=True
+        ).to(torch_device)
+
+        model.train()
+        with torch.no_grad():
+            output_train = model(**inputs_batched, output_hidden_states=True)
+        self.assertTrue((output_train.hidden_states[0][0, -1414:, ...] == 0).all().item())