transformers: Failing to load saved TFBertModel

TF version: 2.2.0-rc1 transformers version: 2.7.0

import tensorflow as tf import transformers print(tf.__version__) print(transformers.__version__) MAX_LEN = 10 model_path = 'saved_model/temp_model' ids = tf.keras.layers.Input((MAX_LEN,), dtype=tf.int32) mask = tf.keras.layers.Input((MAX_LEN,), dtype=tf.int32) token_type_ids = tf.keras.layers.Input((MAX_LEN,), dtype=tf.int32) base_model = transformers.TFBertModel.from_pretrained("bert-base-cased" , output_hidden_states=False) base_output = base_model([ids, mask, token_type_ids]) seq_out, _ = base_output[0], base_output[1] base_model.trainable = False model = tf.keras.models.Model(inputs=[ids, mask, token_type_ids], outputs=[seq_out]) model.compile(optimizer='adam', loss='binary_crossentropy', metrics=['accuracy']) print(model.summary()) model.save(model_path) model = tf.keras.models.load_model(model_path)

Model load fails with the following error:

Traceback (most recent call last): File “/Users/sourabhmaity/anaconda3/lib/python3.7/site-packages/tensorflow/python/util/nest.py”, line 378, in assert_same_structure expand_composites) TypeError: The two structures don’t have the same nested structure.

First structure: type=dict str={‘input_ids’: TensorSpec(shape=(None, 5), dtype=tf.int32, name=‘input_ids’)}

Second structure: type=list str=[TensorSpec(shape=(None, 10), dtype=tf.int32, name=‘inputs/0’), TensorSpec(shape=(None, 10), dtype=tf.int32, name=‘inputs/1’), TensorSpec(shape=(None, 10), dtype=tf.int32, name=‘inputs/2’)]

More specifically: The two namedtuples don’t have the same sequence type. First structure type=dict str={‘input_ids’: TensorSpec(shape=(None, 5), dtype=tf.int32, name=‘input_ids’)} has type dict, while second structure type=list str=[TensorSpec(shape=(None, 10), dtype=tf.int32, name=‘inputs/0’), TensorSpec(shape=(None, 10), dtype=tf.int32, name=‘inputs/1’), TensorSpec(shape=(None, 10), dtype=tf.int32, name=‘inputs/2’)] has type list

During handling of the above exception, another exception occurred:

Traceback (most recent call last): File “temp.py”, line 29, in <module> model = tf.keras.models.load_model(model_path) File “/Users/sourabhmaity/anaconda3/lib/python3.7/site-packages/tensorflow/python/keras/saving/save.py”, line 190, in load_model return saved_model_load.load(filepath, compile) File “/Users/sourabhmaity/anaconda3/lib/python3.7/site-packages/tensorflow/python/keras/saving/saved_model/load.py”, line 116, in load model = tf_load.load_internal(path, loader_cls=KerasObjectLoader) File “/Users/sourabhmaity/anaconda3/lib/python3.7/site-packages/tensorflow/python/saved_model/load.py”, line 604, in load_internal export_dir) File “/Users/sourabhmaity/anaconda3/lib/python3.7/site-packages/tensorflow/python/keras/saving/saved_model/load.py”, line 188, in init super(KerasObjectLoader, self).init(*args, **kwargs) File “/Users/sourabhmaity/anaconda3/lib/python3.7/site-packages/tensorflow/python/saved_model/load.py”, line 123, in init self._load_all() File “/Users/sourabhmaity/anaconda3/lib/python3.7/site-packages/tensorflow/python/keras/saving/saved_model/load.py”, line 215, in _load_all self._finalize_objects() File “/Users/sourabhmaity/anaconda3/lib/python3.7/site-packages/tensorflow/python/keras/saving/saved_model/load.py”, line 506, in _finalize_objects _finalize_saved_model_layers(layers_revived_from_saved_model) File “/Users/sourabhmaity/anaconda3/lib/python3.7/site-packages/tensorflow/python/keras/saving/saved_model/load.py”, line 677, in _finalize_saved_model_layers inputs = infer_inputs_from_restored_call_function(call_fn) File “/Users/sourabhmaity/anaconda3/lib/python3.7/site-packages/tensorflow/python/keras/saving/saved_model/load.py”, line 921, in infer_inputs_from_restored_call_function spec = nest.map_structure(common_spec, spec, spec2) File “/Users/sourabhmaity/anaconda3/lib/python3.7/site-packages/tensorflow/python/util/nest.py”, line 611, in map_structure expand_composites=expand_composites) File “/Users/sourabhmaity/anaconda3/lib/python3.7/site-packages/tensorflow/python/util/nest.py”, line 385, in assert_same_structure % (str(e), str1, str2)) TypeError: The two structures don’t have the same nested structure.

First structure: type=dict str={‘input_ids’: TensorSpec(shape=(None, 5), dtype=tf.int32, name=‘input_ids’)}

Second structure: type=list str=[TensorSpec(shape=(None, 10), dtype=tf.int32, name=‘inputs/0’), TensorSpec(shape=(None, 10), dtype=tf.int32, name=‘inputs/1’), TensorSpec(shape=(None, 10), dtype=tf.int32, name=‘inputs/2’)]

More specifically: The two namedtuples don’t have the same sequence type. First structure type=dict str={‘input_ids’: TensorSpec(shape=(None, 5), dtype=tf.int32, name=‘input_ids’)} has type dict, while second structure type=list str=[TensorSpec(shape=(None, 10), dtype=tf.int32, name=‘inputs/0’), TensorSpec(shape=(None, 10), dtype=tf.int32, name=‘inputs/1’), TensorSpec(shape=(None, 10), dtype=tf.int32, name=‘inputs/2’)] has type list Entire first structure: {‘input_ids’: .} Entire second structure: [., ., .]