torch/_compile.py

# mypy: allow-untyped-defs
"""
APIs related to torch.compile which lazily import torch._dynamo to avoid
circular dependencies.
"""

import functools


def _disable_dynamo(fn=None, recursive=True):
    """
    This API should be only used inside torch, external users should still use
    torch._dynamo.disable. The main goal of this API is to avoid circular
    imports issues that is common while using _dynamo.disable inside torch
    itself.

    This API avoids it by lazily importing torch._dynamo from the import time to
    the invocation of the decorated function.
    """
    if fn is not None:

        @functools.wraps(fn)
        def inner(*args, **kwargs):
            # cache this on the first invocation to avoid adding too much overhead.
            disable_fn = getattr(fn, "__dynamo_disable", None)
            if disable_fn is None:
                import torch._dynamo

                disable_fn = torch._dynamo.disable(fn, recursive)
                fn.__dynamo_disable = disable_fn

            return disable_fn(*args, **kwargs)

        return inner
    else:
        # decorator usage like @_disable_dynamo(recursive=False). The resulting
        # object expects the original decorated function as the arg.
        return functools.partial(_disable_dynamo, recursive=recursive)