git: skeleton of a new extension to _directly_ operate on git repos
This is based in part of work I did years ago in hgit, but it's mostly
new code since I'm using pygit2 instead of dulwich and the hg storage
interfaces have improved. Some cleanup of old hgit code by Pulkit,
which I greatly appreciate.
test-git-interop.t does not cover a whole lot of cases, but it
passes. It includes status, diff, making a new commit, and `hg annotate`
working on the git repository.
This is _not_ (yet) production quality code: this is an
experiment. Known technical debt lurking in this implementation:
* Writing bookmarks just totally ignores transactions.
* The way progress is threaded down into the gitstore is awful.
* Ideally we'd find a way to incrementally reindex DAGs. I'm not sure
how to do that efficiently, so we might need a "known only fast-forwards"
mode on the DAG indexer for use on `hg commit` and friends.
* We don't even _try_ to do anything reasonable for `hg pull` or `hg push`.
* Mercurial need an interface for the changelog type.
Tests currently require git 2.24 as far as I'm aware: `git status` has
some changed output that I didn't try and handle in a compatible way.
This patch has produced some interesting cleanups, most recently on
the manifest type. I expect continuing down this road will produce
other meritorious cleanups throughout our code.
Differential Revision: https://phab.mercurial-scm.org/D6734
# shallowbundle.py - bundle10 implementation for use with shallow repositories
#
# Copyright 2013 Facebook, Inc.
#
# 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
from mercurial.i18n import _
from mercurial.node import bin, hex, nullid
from mercurial import (
bundlerepo,
changegroup,
error,
match,
mdiff,
pycompat,
)
from . import (
constants,
remotefilelog,
shallowutil,
)
NoFiles = 0
LocalFiles = 1
AllFiles = 2
def shallowgroup(cls, self, nodelist, rlog, lookup, units=None, reorder=None):
if not isinstance(rlog, remotefilelog.remotefilelog):
for c in super(cls, self).group(nodelist, rlog, lookup, units=units):
yield c
return
if len(nodelist) == 0:
yield self.close()
return
nodelist = shallowutil.sortnodes(nodelist, rlog.parents)
# add the parent of the first rev
p = rlog.parents(nodelist[0])[0]
nodelist.insert(0, p)
# build deltas
for i in pycompat.xrange(len(nodelist) - 1):
prev, curr = nodelist[i], nodelist[i + 1]
linknode = lookup(curr)
for c in self.nodechunk(rlog, curr, prev, linknode):
yield c
yield self.close()
class shallowcg1packer(changegroup.cgpacker):
def generate(self, commonrevs, clnodes, fastpathlinkrev, source, **kwargs):
if shallowutil.isenabled(self._repo):
fastpathlinkrev = False
return super(shallowcg1packer, self).generate(
commonrevs, clnodes, fastpathlinkrev, source, **kwargs
)
def group(self, nodelist, rlog, lookup, units=None, reorder=None):
return shallowgroup(
shallowcg1packer, self, nodelist, rlog, lookup, units=units
)
def generatefiles(self, changedfiles, *args):
try:
linknodes, commonrevs, source = args
except ValueError:
commonrevs, source, mfdicts, fastpathlinkrev, fnodes, clrevs = args
if shallowutil.isenabled(self._repo):
repo = self._repo
if isinstance(repo, bundlerepo.bundlerepository):
# If the bundle contains filelogs, we can't pull from it, since
# bundlerepo is heavily tied to revlogs. Instead require that
# the user use unbundle instead.
# Force load the filelog data.
bundlerepo.bundlerepository.file(repo, b'foo')
if repo._cgfilespos:
raise error.Abort(
b"cannot pull from full bundles",
hint=b"use `hg unbundle` instead",
)
return []
filestosend = self.shouldaddfilegroups(source)
if filestosend == NoFiles:
changedfiles = list(
[f for f in changedfiles if not repo.shallowmatch(f)]
)
return super(shallowcg1packer, self).generatefiles(changedfiles, *args)
def shouldaddfilegroups(self, source):
repo = self._repo
if not shallowutil.isenabled(repo):
return AllFiles
if source == b"push" or source == b"bundle":
return AllFiles
caps = self._bundlecaps or []
if source == b"serve" or source == b"pull":
if constants.BUNDLE2_CAPABLITY in caps:
return LocalFiles
else:
# Serving to a full repo requires us to serve everything
repo.ui.warn(_(b"pulling from a shallow repo\n"))
return AllFiles
return NoFiles
def prune(self, rlog, missing, commonrevs):
if not isinstance(rlog, remotefilelog.remotefilelog):
return super(shallowcg1packer, self).prune(
rlog, missing, commonrevs
)
repo = self._repo
results = []
for fnode in missing:
fctx = repo.filectx(rlog.filename, fileid=fnode)
if fctx.linkrev() not in commonrevs:
results.append(fnode)
return results
def nodechunk(self, revlog, node, prevnode, linknode):
prefix = b''
if prevnode == nullid:
delta = revlog.rawdata(node)
prefix = mdiff.trivialdiffheader(len(delta))
else:
# Actually uses remotefilelog.revdiff which works on nodes, not revs
delta = revlog.revdiff(prevnode, node)
p1, p2 = revlog.parents(node)
flags = revlog.flags(node)
meta = self.builddeltaheader(node, p1, p2, prevnode, linknode, flags)
meta += prefix
l = len(meta) + len(delta)
yield changegroup.chunkheader(l)
yield meta
yield delta
def makechangegroup(orig, repo, outgoing, version, source, *args, **kwargs):
if not shallowutil.isenabled(repo):
return orig(repo, outgoing, version, source, *args, **kwargs)
original = repo.shallowmatch
try:
# if serving, only send files the clients has patterns for
if source == b'serve':
bundlecaps = kwargs.get('bundlecaps')
includepattern = None
excludepattern = None
for cap in bundlecaps or []:
if cap.startswith(b"includepattern="):
raw = cap[len(b"includepattern=") :]
if raw:
includepattern = raw.split(b'\0')
elif cap.startswith(b"excludepattern="):
raw = cap[len(b"excludepattern=") :]
if raw:
excludepattern = raw.split(b'\0')
if includepattern or excludepattern:
repo.shallowmatch = match.match(
repo.root, b'', None, includepattern, excludepattern
)
else:
repo.shallowmatch = match.always()
return orig(repo, outgoing, version, source, *args, **kwargs)
finally:
repo.shallowmatch = original
def addchangegroupfiles(orig, repo, source, revmap, trp, expectedfiles, *args):
if not shallowutil.isenabled(repo):
return orig(repo, source, revmap, trp, expectedfiles, *args)
newfiles = 0
visited = set()
revisiondatas = {}
queue = []
# Normal Mercurial processes each file one at a time, adding all
# the new revisions for that file at once. In remotefilelog a file
# revision may depend on a different file's revision (in the case
# of a rename/copy), so we must lay all revisions down across all
# files in topological order.
# read all the file chunks but don't add them
progress = repo.ui.makeprogress(_(b'files'), total=expectedfiles)
while True:
chunkdata = source.filelogheader()
if not chunkdata:
break
f = chunkdata[b"filename"]
repo.ui.debug(b"adding %s revisions\n" % f)
progress.increment()
if not repo.shallowmatch(f):
fl = repo.file(f)
deltas = source.deltaiter()
fl.addgroup(deltas, revmap, trp)
continue
chain = None
while True:
# returns: (node, p1, p2, cs, deltabase, delta, flags) or None
revisiondata = source.deltachunk(chain)
if not revisiondata:
break
chain = revisiondata[0]
revisiondatas[(f, chain)] = revisiondata
queue.append((f, chain))
if f not in visited:
newfiles += 1
visited.add(f)
if chain is None:
raise error.Abort(_(b"received file revlog group is empty"))
processed = set()
def available(f, node, depf, depnode):
if depnode != nullid and (depf, depnode) not in processed:
if not (depf, depnode) in revisiondatas:
# It's not in the changegroup, assume it's already
# in the repo
return True
# re-add self to queue
queue.insert(0, (f, node))
# add dependency in front
queue.insert(0, (depf, depnode))
return False
return True
skipcount = 0
# Prefetch the non-bundled revisions that we will need
prefetchfiles = []
for f, node in queue:
revisiondata = revisiondatas[(f, node)]
# revisiondata: (node, p1, p2, cs, deltabase, delta, flags)
dependents = [revisiondata[1], revisiondata[2], revisiondata[4]]
for dependent in dependents:
if dependent == nullid or (f, dependent) in revisiondatas:
continue
prefetchfiles.append((f, hex(dependent)))
repo.fileservice.prefetch(prefetchfiles)
# Apply the revisions in topological order such that a revision
# is only written once it's deltabase and parents have been written.
while queue:
f, node = queue.pop(0)
if (f, node) in processed:
continue
skipcount += 1
if skipcount > len(queue) + 1:
raise error.Abort(_(b"circular node dependency"))
fl = repo.file(f)
revisiondata = revisiondatas[(f, node)]
# revisiondata: (node, p1, p2, cs, deltabase, delta, flags)
node, p1, p2, linknode, deltabase, delta, flags = revisiondata
if not available(f, node, f, deltabase):
continue
base = fl.rawdata(deltabase)
text = mdiff.patch(base, delta)
if not isinstance(text, bytes):
text = bytes(text)
meta, text = shallowutil.parsemeta(text)
if b'copy' in meta:
copyfrom = meta[b'copy']
copynode = bin(meta[b'copyrev'])
if not available(f, node, copyfrom, copynode):
continue
for p in [p1, p2]:
if p != nullid:
if not available(f, node, f, p):
continue
fl.add(text, meta, trp, linknode, p1, p2)
processed.add((f, node))
skipcount = 0
progress.complete()
return len(revisiondatas), newfiles