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
"""utilities to assist in working with pygit2"""
from __future__ import annotations
from mercurial.node import bin, sha1nodeconstants
pygit2_module = None
def get_pygit2():
global pygit2_module
if pygit2_module is None:
try:
import pygit2 as pygit2_module # pytype: disable=import-error
pygit2_module.InvalidSpecError
except (ImportError, AttributeError):
pass
return pygit2_module
def pygit2_version():
mod = get_pygit2()
v = "N/A"
if mod:
try:
v = mod.__version__
except AttributeError:
pass
return b"(pygit2 %s)" % v.encode("utf-8")
def togitnode(n):
"""Wrapper to convert a Mercurial binary node to a unicode hexlified node.
pygit2 and sqlite both need nodes as strings, not bytes.
"""
assert len(n) == 20
return n.hex()
def fromgitnode(n):
"""Opposite of togitnode."""
assert len(n) == 40
return bin(n)
nullgit = togitnode(sha1nodeconstants.nullid)