What is the best way to use mycollate?

[Fei-Wang]

below is my code

from mmengine.dataset import COLLATE_FUNCTIONS as MMENGINE_COLLATE_FUNCTIONS
COLLATE_FUNCTIONS = Registry(
    'Collate Functions',
    parent=MMENGINE_COLLATE_FUNCTIONS,
    locations=['myproject.datasets'],
)

and

@COLLATE_FUNCTIONS.register_module()
def mycollate(data_batch, *args, **kwargs):
    pass

and in myconfig.py

collate = dict(
    type='mycollate',
)
train_dataloader=dict(collate=collate,...)

but, default runner will report error at

mmengine/mmengine/runner/runner.py

Line 1402 in 5753cd9

collate_fn = COLLATE_FUNCTIONS.get(collate_fn_type)

so, what is the best way to use mycollate?

[C1rN09]

There is an issue with Registry.get() method that it will not infer scopes as Registry.build() do. As a result, you have to register your mycollate to MMEngine's own root registry rather than your child registry.

Honestly speaking, this behavior is kind of weird. We will try to find a better solution in the future.