support new marian models (#15831)

* support not sharing embeddings

* update modeling

* update tokenizer

* fix conversion script

* always use self.shared

* boom boom

* begin tests

* update tests

* fix resize_decoder_token_embeddings

* address Patrick's comments

* style

* update conversion script

* fix conversion script

* fix tokenizer

* better name target vocab

* add integration test for tokenizer with two vocabs

* style

* address Patrick's comments

* add integration test for model

tests/marian/test_modeling_marian.py

@@ -268,6 +268,58 @@ class MarianModelTest(ModelTesterMixin, GenerationTesterMixin, unittest.TestCase
         model.generate(input_ids, attention_mask=attention_mask)
         model.generate(num_beams=4, do_sample=True, early_stopping=False, num_return_sequences=3)
 
+    def test_share_encoder_decoder_embeddings(self):
+        config, input_dict = self.model_tester.prepare_config_and_inputs()
+
+        # check if embeddings are shared by default
+        for model_class in self.all_model_classes:
+            model = model_class(config)
+            self.assertIs(model.get_encoder().embed_tokens, model.get_decoder().embed_tokens)
+            self.assertIs(model.get_encoder().embed_tokens.weight, model.get_decoder().embed_tokens.weight)
+
+        # check if embeddings are not shared when config.share_encoder_decoder_embeddings = False
+        config.share_encoder_decoder_embeddings = False
+        for model_class in self.all_model_classes:
+            model = model_class(config)
+            self.assertIsNot(model.get_encoder().embed_tokens, model.get_decoder().embed_tokens)
+            self.assertIsNot(model.get_encoder().embed_tokens.weight, model.get_decoder().embed_tokens.weight)
+
+        # check if a model with shared embeddings can be saved and loaded with share_encoder_decoder_embeddings = False
+        config, _ = self.model_tester.prepare_config_and_inputs()
+        for model_class in self.all_model_classes:
+            model = model_class(config)
+            with tempfile.TemporaryDirectory() as tmpdirname:
+                model.save_pretrained(tmpdirname)
+                model = model_class.from_pretrained(tmpdirname, share_encoder_decoder_embeddings=False)
+                self.assertIsNot(model.get_encoder().embed_tokens, model.get_decoder().embed_tokens)
+                self.assertIsNot(model.get_encoder().embed_tokens.weight, model.get_decoder().embed_tokens.weight)
+
+    def test_resize_decoder_token_embeddings(self):
+        config, _ = self.model_tester.prepare_config_and_inputs()
+
+        # check if resize_decoder_token_embeddings raises an error when embeddings are shared
+        for model_class in self.all_model_classes:
+            model = model_class(config)
+            with self.assertRaises(ValueError):
+                model.resize_decoder_token_embeddings(config.vocab_size + 1)
+
+        # check if decoder embeddings are resized when config.share_encoder_decoder_embeddings = False
+        config.share_encoder_decoder_embeddings = False
+        for model_class in self.all_model_classes:
+            model = model_class(config)
+            model.resize_decoder_token_embeddings(config.vocab_size + 1)
+            self.assertEqual(model.get_decoder().embed_tokens.weight.shape, (config.vocab_size + 1, config.d_model))
+
+        # check if lm_head is also resized
+        config, _ = self.model_tester.prepare_config_and_inputs()
+        config.share_encoder_decoder_embeddings = False
+        model = MarianMTModel(config)
+        model.resize_decoder_token_embeddings(config.vocab_size + 1)
+        self.assertEqual(model.lm_head.weight.shape, (config.vocab_size + 1, config.d_model))
+
+    def test_tie_word_embeddings_decoder(self):
+        pass
+
 
 def assert_tensors_close(a, b, atol=1e-12, prefix=""):
     """If tensors have different shapes, different values or a and b are not both tensors, raise a nice Assertion error."""
@@ -529,6 +581,27 @@ class TestMarian_en_ROMANCE(MarianIntegrationTest):
         self.assertEqual(self.expected_text, [x["translation_text"] for x in output])
 
 
+@require_sentencepiece
+@require_tokenizers
+class TestMarian_FI_EN_V2(MarianIntegrationTest):
+    src = "fi"
+    tgt = "en"
+    src_text = [
+        "minä tykkään kirjojen lukemisesta",
+        "Pidän jalkapallon katsomisesta",
+    ]
+    expected_text = ["I like to read books", "I like watching football"]
+
+    @classmethod
+    def setUpClass(cls) -> None:
+        cls.model_name = "hf-internal-testing/test-opus-tatoeba-fi-en-v2"
+        return cls
+
+    @slow
+    def test_batch_generation_en_fr(self):
+        self._assert_generated_batch_equal_expected()
+
+
 @require_torch
 class TestConversionUtils(unittest.TestCase):
     def test_renaming_multilingual(self):