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localrepo: iteratively derive local repository type...
localrepo: iteratively derive local repository type This commit implements the dynamic local repository type derivation that was explained in the recent commit bfeab472e3c0 "localrepo: create new function for instantiating a local repo object." Instead of a static localrepository class/type which must be customized after construction, we now dynamically construct a type by building up base classes/types to represent specific repository interfaces. Conceptually, the end state is similar to what was happening when various extensions would monkeypatch the __class__ of newly-constructed repo instances. However, the approach is inverted. Instead of making the instance then customizing it, we do the customization up front by influencing the behavior of the type then we instantiate that custom type. This approach gives us much more flexibility. For example, we can use completely separate classes for implementing different aspects of the repository. For example, we could have one class representing revlog-based file storage and another representing non-revlog based file storage. When then choose which implementation to use based on the presence of repo requirements. A concern with this approach is that it creates a lot more types and complexity and that complexity adds overhead. Yes, it is true that this approach will result in more types being created. Yes, this is more complicated than traditional "instantiate a static type." However, I believe the alternatives to supporting alternate storage backends are just as complicated. (Before I arrived at this solution, I had patches storing factory functions on local repo instances for e.g. constructing a file storage instance. We ended up having a handful of these. And this was logically identical to assigning custom methods. Since we were logically changing the type of the instance, I figured it would be better to just use specialized types instead of introducing levels of abstraction at run-time.) On the performance front, I don't believe that having N base classes has any significant performance overhead compared to just a single base class. Intuition says that Python will need to iterate the base classes to find an attribute. However, CPython caches method lookups: as long as the __class__ or MRO isn't changing, method attribute lookup should be constant time after first access. And non-method attributes are stored in __dict__, of which there is only 1 per object, so the number of base classes for __dict__ is irrelevant. Anyway, this commit splits up the monolithic completelocalrepository interface into sub-interfaces: 1 for file storage and 1 representing everything else. We've taught ``makelocalrepository()`` to call a series of factory functions which will produce types implementing specific interfaces. It then calls type() to create a new type from the built-up list of base types. This commit should be considered a start and not the end state. I suspect we'll hit a number of problems as we start to implement alternate storage backends: * Passing custom arguments to __init__ and setting custom attributes on __dict__. * Customizing the set of interfaces that are needed. e.g. the "readonly" intent could translate to not requesting an interface providing methods related to writing. * More ergonomic way for extensions to insert themselves so their callbacks aren't unconditionally called. * Wanting to modify vfs instances, other arguments passed to __init__. That being said, this code is usable in its current state and I'm convinced future commits will demonstrate the value in this approach. Differential Revision: https://phab.mercurial-scm.org/D4642

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subrepoutil.py
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# subrepoutil.py - sub-repository operations and substate handling
#
# Copyright 2009-2010 Matt Mackall <mpm@selenic.com>
#
# 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 absolute_import
import errno
import os
import posixpath
import re
from .i18n import _
from . import (
config,
error,
filemerge,
pathutil,
phases,
util,
)
from .utils import (
stringutil,
)
nullstate = ('', '', 'empty')
def state(ctx, ui):
"""return a state dict, mapping subrepo paths configured in .hgsub
to tuple: (source from .hgsub, revision from .hgsubstate, kind
(key in types dict))
"""
p = config.config()
repo = ctx.repo()
def read(f, sections=None, remap=None):
if f in ctx:
try:
data = ctx[f].data()
except IOError as err:
if err.errno != errno.ENOENT:
raise
# handle missing subrepo spec files as removed
ui.warn(_("warning: subrepo spec file \'%s\' not found\n") %
repo.pathto(f))
return
p.parse(f, data, sections, remap, read)
else:
raise error.Abort(_("subrepo spec file \'%s\' not found") %
repo.pathto(f))
if '.hgsub' in ctx:
read('.hgsub')
for path, src in ui.configitems('subpaths'):
p.set('subpaths', path, src, ui.configsource('subpaths', path))
rev = {}
if '.hgsubstate' in ctx:
try:
for i, l in enumerate(ctx['.hgsubstate'].data().splitlines()):
l = l.lstrip()
if not l:
continue
try:
revision, path = l.split(" ", 1)
except ValueError:
raise error.Abort(_("invalid subrepository revision "
"specifier in \'%s\' line %d")
% (repo.pathto('.hgsubstate'), (i + 1)))
rev[path] = revision
except IOError as err:
if err.errno != errno.ENOENT:
raise
def remap(src):
for pattern, repl in p.items('subpaths'):
# Turn r'C:\foo\bar' into r'C:\\foo\\bar' since re.sub
# does a string decode.
repl = stringutil.escapestr(repl)
# However, we still want to allow back references to go
# through unharmed, so we turn r'\\1' into r'\1'. Again,
# extra escapes are needed because re.sub string decodes.
repl = re.sub(br'\\\\([0-9]+)', br'\\\1', repl)
try:
src = re.sub(pattern, repl, src, 1)
except re.error as e:
raise error.Abort(_("bad subrepository pattern in %s: %s")
% (p.source('subpaths', pattern),
stringutil.forcebytestr(e)))
return src
state = {}
for path, src in p[''].items():
kind = 'hg'
if src.startswith('['):
if ']' not in src:
raise error.Abort(_('missing ] in subrepository source'))
kind, src = src.split(']', 1)
kind = kind[1:]
src = src.lstrip() # strip any extra whitespace after ']'
if not util.url(src).isabs():
parent = _abssource(repo, abort=False)
if parent:
parent = util.url(parent)
parent.path = posixpath.join(parent.path or '', src)
parent.path = posixpath.normpath(parent.path)
joined = bytes(parent)
# Remap the full joined path and use it if it changes,
# else remap the original source.
remapped = remap(joined)
if remapped == joined:
src = remap(src)
else:
src = remapped
src = remap(src)
state[util.pconvert(path)] = (src.strip(), rev.get(path, ''), kind)
return state
def writestate(repo, state):
"""rewrite .hgsubstate in (outer) repo with these subrepo states"""
lines = ['%s %s\n' % (state[s][1], s) for s in sorted(state)
if state[s][1] != nullstate[1]]
repo.wwrite('.hgsubstate', ''.join(lines), '')
def submerge(repo, wctx, mctx, actx, overwrite, labels=None):
"""delegated from merge.applyupdates: merging of .hgsubstate file
in working context, merging context and ancestor context"""
if mctx == actx: # backwards?
actx = wctx.p1()
s1 = wctx.substate
s2 = mctx.substate
sa = actx.substate
sm = {}
repo.ui.debug("subrepo merge %s %s %s\n" % (wctx, mctx, actx))
def debug(s, msg, r=""):
if r:
r = "%s:%s:%s" % r
repo.ui.debug(" subrepo %s: %s %s\n" % (s, msg, r))
promptssrc = filemerge.partextras(labels)
for s, l in sorted(s1.iteritems()):
prompts = None
a = sa.get(s, nullstate)
ld = l # local state with possible dirty flag for compares
if wctx.sub(s).dirty():
ld = (l[0], l[1] + "+")
if wctx == actx: # overwrite
a = ld
prompts = promptssrc.copy()
prompts['s'] = s
if s in s2:
r = s2[s]
if ld == r or r == a: # no change or local is newer
sm[s] = l
continue
elif ld == a: # other side changed
debug(s, "other changed, get", r)
wctx.sub(s).get(r, overwrite)
sm[s] = r
elif ld[0] != r[0]: # sources differ
prompts['lo'] = l[0]
prompts['ro'] = r[0]
if repo.ui.promptchoice(
_(' subrepository sources for %(s)s differ\n'
'use (l)ocal%(l)s source (%(lo)s)'
' or (r)emote%(o)s source (%(ro)s)?'
'$$ &Local $$ &Remote') % prompts, 0):
debug(s, "prompt changed, get", r)
wctx.sub(s).get(r, overwrite)
sm[s] = r
elif ld[1] == a[1]: # local side is unchanged
debug(s, "other side changed, get", r)
wctx.sub(s).get(r, overwrite)
sm[s] = r
else:
debug(s, "both sides changed")
srepo = wctx.sub(s)
prompts['sl'] = srepo.shortid(l[1])
prompts['sr'] = srepo.shortid(r[1])
option = repo.ui.promptchoice(
_(' subrepository %(s)s diverged (local revision: %(sl)s, '
'remote revision: %(sr)s)\n'
'(M)erge, keep (l)ocal%(l)s or keep (r)emote%(o)s?'
'$$ &Merge $$ &Local $$ &Remote')
% prompts, 0)
if option == 0:
wctx.sub(s).merge(r)
sm[s] = l
debug(s, "merge with", r)
elif option == 1:
sm[s] = l
debug(s, "keep local subrepo revision", l)
else:
wctx.sub(s).get(r, overwrite)
sm[s] = r
debug(s, "get remote subrepo revision", r)
elif ld == a: # remote removed, local unchanged
debug(s, "remote removed, remove")
wctx.sub(s).remove()
elif a == nullstate: # not present in remote or ancestor
debug(s, "local added, keep")
sm[s] = l
continue
else:
if repo.ui.promptchoice(
_(' local%(l)s changed subrepository %(s)s'
' which remote%(o)s removed\n'
'use (c)hanged version or (d)elete?'
'$$ &Changed $$ &Delete') % prompts, 0):
debug(s, "prompt remove")
wctx.sub(s).remove()
for s, r in sorted(s2.items()):
prompts = None
if s in s1:
continue
elif s not in sa:
debug(s, "remote added, get", r)
mctx.sub(s).get(r)
sm[s] = r
elif r != sa[s]:
prompts = promptssrc.copy()
prompts['s'] = s
if repo.ui.promptchoice(
_(' remote%(o)s changed subrepository %(s)s'
' which local%(l)s removed\n'
'use (c)hanged version or (d)elete?'
'$$ &Changed $$ &Delete') % prompts, 0) == 0:
debug(s, "prompt recreate", r)
mctx.sub(s).get(r)
sm[s] = r
# record merged .hgsubstate
writestate(repo, sm)
return sm
def precommit(ui, wctx, status, match, force=False):
"""Calculate .hgsubstate changes that should be applied before committing
Returns (subs, commitsubs, newstate) where
- subs: changed subrepos (including dirty ones)
- commitsubs: dirty subrepos which the caller needs to commit recursively
- newstate: new state dict which the caller must write to .hgsubstate
This also updates the given status argument.
"""
subs = []
commitsubs = set()
newstate = wctx.substate.copy()
# only manage subrepos and .hgsubstate if .hgsub is present
if '.hgsub' in wctx:
# we'll decide whether to track this ourselves, thanks
for c in status.modified, status.added, status.removed:
if '.hgsubstate' in c:
c.remove('.hgsubstate')
# compare current state to last committed state
# build new substate based on last committed state
oldstate = wctx.p1().substate
for s in sorted(newstate.keys()):
if not match(s):
# ignore working copy, use old state if present
if s in oldstate:
newstate[s] = oldstate[s]
continue
if not force:
raise error.Abort(
_("commit with new subrepo %s excluded") % s)
dirtyreason = wctx.sub(s).dirtyreason(True)
if dirtyreason:
if not ui.configbool('ui', 'commitsubrepos'):
raise error.Abort(dirtyreason,
hint=_("use --subrepos for recursive commit"))
subs.append(s)
commitsubs.add(s)
else:
bs = wctx.sub(s).basestate()
newstate[s] = (newstate[s][0], bs, newstate[s][2])
if oldstate.get(s, (None, None, None))[1] != bs:
subs.append(s)
# check for removed subrepos
for p in wctx.parents():
r = [s for s in p.substate if s not in newstate]
subs += [s for s in r if match(s)]
if subs:
if (not match('.hgsub') and
'.hgsub' in (wctx.modified() + wctx.added())):
raise error.Abort(_("can't commit subrepos without .hgsub"))
status.modified.insert(0, '.hgsubstate')
elif '.hgsub' in status.removed:
# clean up .hgsubstate when .hgsub is removed
if ('.hgsubstate' in wctx and
'.hgsubstate' not in (status.modified + status.added +
status.removed)):
status.removed.insert(0, '.hgsubstate')
return subs, commitsubs, newstate
def reporelpath(repo):
"""return path to this (sub)repo as seen from outermost repo"""
parent = repo
while util.safehasattr(parent, '_subparent'):
parent = parent._subparent
return repo.root[len(pathutil.normasprefix(parent.root)):]
def subrelpath(sub):
"""return path to this subrepo as seen from outermost repo"""
return sub._relpath
def _abssource(repo, push=False, abort=True):
"""return pull/push path of repo - either based on parent repo .hgsub info
or on the top repo config. Abort or return None if no source found."""
if util.safehasattr(repo, '_subparent'):
source = util.url(repo._subsource)
if source.isabs():
return bytes(source)
source.path = posixpath.normpath(source.path)
parent = _abssource(repo._subparent, push, abort=False)
if parent:
parent = util.url(util.pconvert(parent))
parent.path = posixpath.join(parent.path or '', source.path)
parent.path = posixpath.normpath(parent.path)
return bytes(parent)
else: # recursion reached top repo
path = None
if util.safehasattr(repo, '_subtoppath'):
path = repo._subtoppath
elif push and repo.ui.config('paths', 'default-push'):
path = repo.ui.config('paths', 'default-push')
elif repo.ui.config('paths', 'default'):
path = repo.ui.config('paths', 'default')
elif repo.shared():
# chop off the .hg component to get the default path form. This has
# already run through vfsmod.vfs(..., realpath=True), so it doesn't
# have problems with 'C:'
return os.path.dirname(repo.sharedpath)
if path:
# issue5770: 'C:\' and 'C:' are not equivalent paths. The former is
# as expected: an absolute path to the root of the C: drive. The
# latter is a relative path, and works like so:
#
# C:\>cd C:\some\path
# C:\>D:
# D:\>python -c "import os; print os.path.abspath('C:')"
# C:\some\path
#
# D:\>python -c "import os; print os.path.abspath('C:relative')"
# C:\some\path\relative
if util.hasdriveletter(path):
if len(path) == 2 or path[2:3] not in br'\/':
path = os.path.abspath(path)
return path
if abort:
raise error.Abort(_("default path for subrepository not found"))
def newcommitphase(ui, ctx):
commitphase = phases.newcommitphase(ui)
substate = getattr(ctx, "substate", None)
if not substate:
return commitphase
check = ui.config('phases', 'checksubrepos')
if check not in ('ignore', 'follow', 'abort'):
raise error.Abort(_('invalid phases.checksubrepos configuration: %s')
% (check))
if check == 'ignore':
return commitphase
maxphase = phases.public
maxsub = None
for s in sorted(substate):
sub = ctx.sub(s)
subphase = sub.phase(substate[s][1])
if maxphase < subphase:
maxphase = subphase
maxsub = s
if commitphase < maxphase:
if check == 'abort':
raise error.Abort(_("can't commit in %s phase"
" conflicting %s from subrepository %s") %
(phases.phasenames[commitphase],
phases.phasenames[maxphase], maxsub))
ui.warn(_("warning: changes are committed in"
" %s phase from subrepository %s\n") %
(phases.phasenames[maxphase], maxsub))
return maxphase
return commitphase