interfaces: introduce and use a protocol class for the `bdiff` module
This is allowed by PEP 544[1], and we basically follow the example there. The
class here is copied from `mercurial.pure.bdiff`, and the implementation
removed.
There are several modules that have a few different implementations, and the
implementation chosen is controlled by `HGMODULEPOLICY`. The module is loaded
via `mercurial/policy.py`, and has been inferred by pytype as `Any` up to this
point. Therefore it and PyCharm were blind to all functions on the module, and
their signatures. Also, having multiple instances of the same module allows
their signatures to get out of sync.
Introducing a protocol class allows the loaded module that is stored in a
variable to be given type info, which cascades through the various places it is
used. This change alters 11 *.pyi files, for example. In theory, this would
also allow us to ensure the various implementations of the same module are kept
in alignment- simply import the module in a test module, attempt to pass it to a
function that uses the corresponding protocol as an argument, and run pytype on
it.
In practice, this doesn't work (yet). PyCharm (erroneously) flags imported
modules being passed where a protocol class is used[2]. Pytype has problems the
other way- it fails to detect when a module that doesn't adhere to the protocol
is passed to a protocol argument. The good news is that mypy properly detects
this case. The bad news is that mypy spews a bunch of other errors when
importing even simple modules, like the various `bdiff` modules. Therefore I'm
punting on the tests for now because the type info around a loaded module in
PyCharm is a clear win by itself.
[1] https://peps.python.org/pep-0544/#modules-as-implementations-of-protocols
[2] https://youtrack.jetbrains.com/issue/PY-58679/Support-modules-implementing-protocols
# darcs.py - darcs support for the convert extension
#
# Copyright 2007-2009 Olivia Mackall <olivia@selenic.com> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from __future__ import annotations
import os
import re
import shutil
from xml.etree.ElementTree import (
ElementTree,
XMLParser,
)
from mercurial.i18n import _
from mercurial import (
error,
pycompat,
util,
)
from mercurial.utils import dateutil
from . import common
NoRepo = common.NoRepo
class darcs_source(common.converter_source, common.commandline):
def __init__(self, ui, repotype, path, revs=None):
common.converter_source.__init__(self, ui, repotype, path, revs=revs)
common.commandline.__init__(self, ui, b'darcs')
# check for _darcs, ElementTree so that we can easily skip
# test-convert-darcs if ElementTree is not around
if not os.path.exists(os.path.join(path, b'_darcs')):
raise NoRepo(_(b"%s does not look like a darcs repository") % path)
common.checktool(b'darcs')
version = self.run0(b'--version').splitlines()[0].strip()
if version < b'2.1':
raise error.Abort(
_(b'darcs version 2.1 or newer needed (found %r)') % version
)
if "ElementTree" not in globals():
raise error.Abort(_(b"Python ElementTree module is not available"))
self.path = os.path.realpath(path)
self.lastrev = None
self.changes = {}
self.parents = {}
self.tags = {}
# Check darcs repository format
format = self.format()
if format:
if format in (b'darcs-1.0', b'hashed'):
raise NoRepo(
_(
b"%s repository format is unsupported, "
b"please upgrade"
)
% format
)
else:
self.ui.warn(_(b'failed to detect repository format!'))
def before(self):
self.tmppath = pycompat.mkdtemp(
prefix=b'convert-' + os.path.basename(self.path) + b'-'
)
output, status = self.run(b'init', repodir=self.tmppath)
self.checkexit(status)
tree = self.xml(
b'changes', xml_output=True, summary=True, repodir=self.path
)
tagname = None
child = None
for elt in tree.findall('patch'):
node = self.recode(elt.get('hash'))
name = self.recode(elt.findtext('name', ''))
if name.startswith(b'TAG '):
tagname = name[4:].strip()
elif tagname is not None:
self.tags[tagname] = node
tagname = None
self.changes[node] = elt
self.parents[child] = [node]
child = node
self.parents[child] = []
def after(self):
self.ui.debug(b'cleaning up %s\n' % self.tmppath)
shutil.rmtree(self.tmppath, ignore_errors=True)
def recode(self, s, encoding=None):
if isinstance(s, str):
# XMLParser returns unicode objects for anything it can't
# encode into ASCII. We convert them back to str to get
# recode's normal conversion behavior.
s = s.encode('latin-1')
return super(darcs_source, self).recode(s, encoding)
def xml(self, cmd, **kwargs):
# NOTE: darcs is currently encoding agnostic and will print
# patch metadata byte-for-byte, even in the XML changelog.
etree = ElementTree()
# While we are decoding the XML as latin-1 to be as liberal as
# possible, etree will still raise an exception if any
# non-printable characters are in the XML changelog.
parser = XMLParser(encoding='latin-1')
p = self._run(cmd, **kwargs)
etree.parse(p.stdout, parser=parser)
p.wait()
self.checkexit(p.returncode)
return etree.getroot()
def format(self):
output, status = self.run(b'show', b'repo', repodir=self.path)
self.checkexit(status)
m = re.search(br'^\s*Format:\s*(.*)$', output, re.MULTILINE)
if not m:
return None
return b','.join(sorted(f.strip() for f in m.group(1).split(b',')))
def manifest(self):
man = []
output, status = self.run(
b'show', b'files', no_directories=True, repodir=self.tmppath
)
self.checkexit(status)
for line in output.split(b'\n'):
path = line[2:]
if path:
man.append(path)
return man
def getheads(self):
return self.parents[None]
def getcommit(self, rev):
elt = self.changes[rev]
dateformat = b'%a %b %d %H:%M:%S %Z %Y'
date = dateutil.strdate(self.recode(elt.get('local_date')), dateformat)
desc = elt.findtext('name') + '\n' + elt.findtext('comment', '')
# etree can return unicode objects for name, comment, and author,
# so recode() is used to ensure str objects are emitted.
newdateformat = b'%Y-%m-%d %H:%M:%S %1%2'
return common.commit(
author=self.recode(elt.get('author')),
date=dateutil.datestr(date, newdateformat),
desc=self.recode(desc).strip(),
parents=self.parents[rev],
)
def pull(self, rev):
output, status = self.run(
b'pull',
self.path,
all=True,
match=b'hash %s' % self.recode(rev),
no_test=True,
no_posthook=True,
external_merge=b'/bin/false',
repodir=self.tmppath,
)
if status:
if output.find(b'We have conflicts in') == -1:
self.checkexit(status, output)
output, status = self.run(b'revert', all=True, repodir=self.tmppath)
self.checkexit(status, output)
def getchanges(self, rev, full):
if full:
raise error.Abort(_(b"convert from darcs does not support --full"))
copies = {}
changes = []
man = None
for elt in self.changes[rev].find('summary'):
if elt.tag in ('add_directory', 'remove_directory'):
continue
if elt.tag == 'move':
if man is None:
man = self.manifest()
source = self.recode(elt.get('from'))
dest = self.recode(elt.get('to'))
if source in man:
# File move
changes.append((source, rev))
changes.append((dest, rev))
copies[dest] = source
else:
# Directory move, deduce file moves from manifest
source = source + b'/'
for f in man:
if not f.startswith(source):
continue
fdest = dest + b'/' + f[len(source) :]
changes.append((f, rev))
changes.append((fdest, rev))
copies[fdest] = f
else:
changes.append((self.recode(elt.text.strip()), rev))
self.pull(rev)
self.lastrev = rev
return sorted(changes), copies, set()
def getfile(self, name, rev):
if rev != self.lastrev:
raise error.Abort(_(b'internal calling inconsistency'))
path = os.path.join(self.tmppath, name)
try:
data = util.readfile(path)
mode = os.lstat(path).st_mode
except FileNotFoundError:
return None, None
mode = (mode & 0o111) and b'x' or b''
return data, mode
def gettags(self):
return self.tags