# Buggy code
def changed_cache_file(self, hash_):
    """Compare the given hash with the (corresponding) actual one.

    - Use `State` as a cache for computed hashes
        + The entries are invalidated by taking into account the following:
            * mtime
            * inode
            * size
            * hash

    - Remove the file from cache if it doesn't match the actual hash
    """
    # Prefer string path over PathInfo when possible due to performance
    cache_info = self.hash_to_path(hash_)
    if self.tree.is_protected(cache_info):
        logger.debug("Assuming '%s' is unchanged since it is read-only", cache_info)
        return False

    _, actual = self.tree.get_hash(cache_info)

    logger.debug(
        "cache '%s' expected '%s' actual '%s'",
        cache_info,
        hash_,
        actual,
    )

    if not hash_ or not actual:
        return True

    if actual.split(".")[0] == hash_.split(".")[0]:
        # making cache file read-only so we don't need to check it
        # next time
        self.tree.protect(cache_info)
        return False

    if self.tree.exists(cache_info):
        logger.warning("corrupted cache file '%s'.", cache_info)
        self.tree.remove(cache_info)

    return True


# Traceback (dvc.exceptions.RemoteCacheRequiredError)
2020-07-01 17:14:02,947 DEBUG: fetched: [(3,)]
2020-07-01 17:14:03,123 DEBUG: Removing output 'some_target' of stage: 'some_target.dvc'.
Importing 's3://some_bucket/some_target' -> 'some_target'
2020-07-01 17:14:03,123 DEBUG: Computed stage: 'some_target.dvc' md5: '2f8b87d3b22efd1638f414c3b3f65614'
2020-07-01 17:14:03,123 DEBUG: 'md5' of stage: 'some_target.dvc' changed.
2020-07-01 17:14:04,088 DEBUG: fetched: [(0,)]
2020-07-01 17:14:04,146 ERROR: failed to import s3://some_bucket/some_target. You could also try downloading it manually, and adding it with `dvc add`. - Current operation was unsuccessful because 's3://some_bucket/some_target' requires existing cache on 's3' remote. See <https://man.dvc.org/config#cache> for information on how to set up remote cache.
------------------------------------------------------------
Traceback (most recent call last):
File "/usr/lib/python3.8/site-packages/dvc/command/imp_url.py", line 14, in run
self.repo.imp_url(
File "/usr/lib/python3.8/site-packages/dvc/repo/__init__.py", line 36, in wrapper
ret = f(repo, *args, **kwargs)
File "/usr/lib/python3.8/site-packages/dvc/repo/scm_context.py", line 4, in run
result = method(repo, *args, **kw)
File "/usr/lib/python3.8/site-packages/dvc/repo/imp_url.py", line 54, in imp_url
stage.run()
File "/home/anotherbugmaster/.local/lib/python3.8/site-packages/funcy/decorators.py", line 39, in wrapper
return deco(call, *dargs, **dkwargs)
File "/usr/lib/python3.8/site-packages/dvc/stage/decorators.py", line 35, in rwlocked
return call()
File "/home/anotherbugmaster/.local/lib/python3.8/site-packages/funcy/decorators.py", line 60, in __call__
return self._func(*self._args, **self._kwargs)
File "/usr/lib/python3.8/site-packages/dvc/stage/__init__.py", line 424, in run
sync_import(self, dry, force)
File "/usr/lib/python3.8/site-packages/dvc/stage/imports.py", line 29, in sync_import
stage.save_deps()
File "/usr/lib/python3.8/site-packages/dvc/stage/__init__.py", line 387, in save_deps
dep.save()
File "/usr/lib/python3.8/site-packages/dvc/output/base.py", line 268, in save
self.info = self.save_info()
File "/usr/lib/python3.8/site-packages/dvc/output/base.py", line 192, in save_info
return self.remote.save_info(self.path_info)
File "/usr/lib/python3.8/site-packages/dvc/remote/base.py", line 762, in save_info
return self.tree.save_info(path_info, **kwargs)
File "/usr/lib/python3.8/site-packages/dvc/remote/base.py", line 329, in save_info
self.PARAM_CHECKSUM: self.get_hash(path_info, tree=tree, **kwargs)
File "/usr/lib/python3.8/site-packages/dvc/remote/base.py", line 297, in get_hash
hash_ = self.get_dir_hash(path_info, tree, **kwargs)
File "/usr/lib/python3.8/site-packages/dvc/remote/base.py", line 311, in get_dir_hash
raise RemoteCacheRequiredError(path_info)
dvc.exceptions.RemoteCacheRequiredError: Current operation was unsuccessful because 's3://some_bucket/some_target' requires existing cache on 's3' remote. See <https://man.dvc.org/config#cache> for information on how to set up remote cache.
------------------------------------------------------------

Having any troubles? Hit us up at https://dvc.org/support, we are always happy to help!

# Fixed code
def changed_cache_file(self, hash_):
    """Compare the given hash with the (corresponding) actual one.

    - Use `State` as a cache for computed hashes
        + The entries are invalidated by taking into account the following:
            * mtime
            * inode
            * size
            * hash

    - Remove the file from cache if it doesn't match the actual hash
    """
    # Prefer string path over PathInfo when possible due to performance
    cache_info = self.hash_to_path(hash_)
    if self.tree.is_protected(cache_info):
        logger.debug("Assuming '%s' is unchanged since it is read-only", cache_info)
        return False

    actual = self.tree.get_hash(cache_info)

    logger.debug(
        "cache '%s' expected '%s' actual '%s'",
        cache_info,
        hash_,
        actual,
    )

    if not hash_ or not actual:
        return True

    if actual.value.split(".")[0] == hash_.split(".")[0]:
        # making cache file read-only so we don't need to check it
        # next time
        self.tree.protect(cache_info)
        return False

    if self.tree.exists(cache_info):
        logger.warning("corrupted cache file '%s'.", cache_info)
        self.tree.remove(cache_info)

    return True