typing: add `from __future__ import annotations` to most files Now that py36 is no longer supported, we can postpone annotation evaluation. This means that the quoting is usually optional (for things imported under the guard of `if typing.TYPE_CHECKING:` to avoid circular imports), and there's less overhead on startup[1]. There may be some missing here. I backed out 6000f5b25c9b (which removed the `from __future__ import ...` that was supporting py2), reverted the changes in `contrib/`, `doc/`, and `tests/`, and then ran: $ hg status -n --change . | \ xargs sed -i -e 's/from __future__ import .*$/from __future__ import annotations/' There were some minor tweaks needed when reviewing (mostly making the spacing around the import consistent, and `mercurial/testing/__init__.py` had a multiline import that wasn't fully rewritten. [1] https://docs.python.org/3/whatsnew/3.7.html#pep-563-postponed-evaluation-of-annotations

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# scmutil.py - Mercurial core utility functions

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#

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#  Copyright Olivia Mackall <olivia@selenic.com> and other

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#

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# This software may be used and distributed according to the terms of the

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# GNU General Public License version 2 or any later version.

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from __future__ import annotations

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from . import repoview

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def cachetocopy(srcrepo):

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    """return the list of cache file valuable to copy during a clone"""

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    # In local clones we're copying all nodes, not just served

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    # ones. Therefore copy all branch caches over.

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    cachefiles = [b'branch2']

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    cachefiles += [b'branch2-%s' % f for f in repoview.filtertable]

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    cachefiles += [b'branch3']

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    cachefiles += [b'branch3-%s' % f for f in repoview.filtertable]

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    cachefiles += [b'rbc-names-v1', b'rbc-revs-v1']

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    cachefiles += [b'tags2']

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    cachefiles += [b'tags2-%s' % f for f in repoview.filtertable]

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    cachefiles += [b'hgtagsfnodes1']

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    return cachefiles