evolve: always create commit when resolving divergence
When resolving content-divergence, the final commit we create may end
up empty (which means that Mercurial won't even create it). We've had
code for handling that in evolve ever since 41bf6c27a122 (evolve:
stabilize now handle conflicting changeset, 2012-08-23). However, that
resolved the issue by marking on the divergent commits as
successor. As Pierre-Yves has pointed out (in other code reviews), we
should instead be creating a new successor. So that's what this patch
does. It does that by setting `ui.allowemptycommit` while creating the
final commit. However, that is not enough, because we may end up
creating the same nodeid as already existed (we'd then end up trying
to mark the "new" commit a successor of itself). To solve that, we add
some salt to the commit extras. That salt affects lots of tests.
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
"""
This file contains class to wrap the state for commands and other
related logic.
All the data related to the command state is stored as dictionary in the object.
The class has methods using which the data can be stored to disk in a file under
.hg/ directory.
We store the data on disk in cbor, for which we use cbor library to serialize
and deserialize data.
"""
from __future__ import absolute_import
import contextlib
import errno
import struct
from .thirdparty import cbor
from mercurial import (
error,
util,
)
from mercurial.i18n import _
class cmdstate(object):
"""a wrapper class to store the state of commands like `evolve`, `pick`
All the data for the state is stored in the form of key-value pairs in a
dictionary.
The class object can write all the data to a file in .hg/ directory and also
can populate the object data reading that file
"""
def __init__(self, repo, path=b'evolvestate', opts=None):
self._repo = repo
self.path = path
if opts is None:
opts = {}
self.opts = opts
def __nonzero__(self):
return self.exists()
__bool__ = __nonzero__
def __contains__(self, key):
return key in self.opts
def __getitem__(self, key):
return self.opts[key]
def get(self, key, default=None):
return self.opts.get(key, default)
def __setitem__(self, key, value):
updates = {key: value}
self.opts.update(updates)
def load(self):
"""load the existing evolvestate file into the class object"""
op = self._read()
if isinstance(op, dict):
self.opts.update(op)
elif self.path == b'evolvestate':
# it is the old evolvestate file
oldop = _oldevolvestateread(self._repo)
self.opts.update(oldop)
def addopts(self, opts):
"""add more key-value pairs to the data stored by the object"""
self.opts.update(opts)
def save(self):
"""write all the evolvestate data stored in .hg/evolvestate file
we use third-party library cbor to serialize data to write in the file.
"""
with self._repo.vfs(self.path, b'wb', atomictemp=True) as fp:
cbor.dump(self.opts, fp)
def _read(self):
"""reads the evolvestate file and returns a dictionary which contain
data in the same format as it was before storing"""
with self._repo.vfs(self.path, b'rb') as fp:
return cbor.load(fp)
def delete(self):
"""drop the evolvestate file if exists"""
util.unlinkpath(self._repo.vfs.join(self.path), ignoremissing=True)
def exists(self):
"""check whether the evolvestate file exists or not"""
return self._repo.vfs.exists(self.path)
def _oldevolvestateread(repo):
"""function to read the old evolvestate file
This exists for BC reasons."""
try:
f = repo.vfs(b'evolvestate')
except IOError as err:
if err.errno != errno.ENOENT:
raise
try:
versionblob = f.read(4)
if len(versionblob) < 4:
repo.ui.debug(b'ignoring corrupted evolvestate (file contains %i bits)'
% len(versionblob))
return None
version = struct.unpack(b'>I', versionblob)[0]
if version != 0:
msg = _(b'unknown evolvestate version %i') % version
raise error.Abort(msg, hint=_(b'upgrade your evolve'))
records = []
data = f.read()
off = 0
end = len(data)
while off < end:
rtype = data[off]
off += 1
length = struct.unpack(b'>I', data[off:(off + 4)])[0]
off += 4
record = data[off:(off + length)]
off += length
if rtype == b't':
rtype, record = record[0], record[1:]
records.append((rtype, record))
state = {}
for rtype, rdata in records:
if rtype == b'C':
state[b'current'] = rdata
elif rtype.lower():
repo.ui.debug(b'ignore evolve state record type %s' % rtype)
else:
raise error.Abort(_(b"unknown evolvestate field type '%s'")
% rtype, hint=_(b'upgrade your evolve'))
return state
finally:
f.close()
@contextlib.contextmanager
def saver(state, opts=None):
"""ensure the state is saved on disk during the duration of the context
The state is preserved if the context is exited through an exception.
"""
if opts:
state.addopts(opts)
state.save()
yield
# delete only if no exception where raised
state.delete()