commit: improve the files field of changelog for merges
Currently, the files list of merge commits repeats all the deletions
(either actual deletions, or files that got renamed) that happened
between base and p2 of the merge. If p2 is the main branch, the list
can easily be much bigger than the change being merged.
This results in various problems worth improving:
- changelog is bigger than necessary
- `hg log directory` lists many unrelated merge commits, and `hg log
-v -r commit` frequently fills multiple screens worth of files
- it possibly slows down adjustlinkrev, by forcing it to read more
manifests, and that function can certainly be a bottleneck
- the server side of pulls can waste a lot of time simply opening the
filelogs for pointless files (the constant factors for opening even
a tiny filelog is apparently pretty bad)
So stop listing such files as described in the code. Impacted merge
commits and their descendants get a different hash than they would
have without this. This doesn't seem problematic, except for
convert. The previous commit helped with that in the hg->hg case (but
if you do svn->hg twice from scratch, hashes can still change).
The rest of the description is numbers. I don't have much to report,
because recreating the files list of existing repositories is not
easy:
- debugupgradeformat and bundle/unbundle don't recreate the list
- export/import tends to choke quickly applying patches or on
description that contain diffs,
- merge commits from the convert extension don't have the right files
list for reasons orthogonal to the current commit
- replaying the merge with hg update/hg merge/hg revert --all/hg
commit can end up failing in hg revert
- I wasn't sure that using debugsetparents + debugrebuilddirstate
would really build the right thing
I measured commit time before and after this change, in a case with no
files filtered out, several files filtered out (no difference) and 5k
files filtered out (+1% time).
Recreating the 100 more recent merges in a private repo, the
concatenated uncompressed files lists goes from 1.12MB to
0.52MB. Excluding 3 merges that are not representative, then the size
goes from 570k to 15k.
I converted part of mozilla-central, and observed file list shrinking
quite a bit too, starting at the very first merge,
733641d9feaf, going
from 550 files to 10 files (although they have relatively few merges,
so they probably wouldn't care).
Differential Revision: https://phab.mercurial-scm.org/D6613
# drawdag.py - convert ASCII revision DAG to actual changesets
#
# Copyright 2016 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.
"""
create changesets from an ASCII graph for testing purpose.
For example, given the following input::
c d
|/
b
|
a
4 changesets and 4 local tags will be created.
`hg log -G -T "{rev} {desc} (tag: {tags})"` will output::
o 3 d (tag: d tip)
|
| o 2 c (tag: c)
|/
o 1 b (tag: b)
|
o 0 a (tag: a)
For root nodes (nodes without parents) in the graph, they can be revsets
pointing to existing nodes. The ASCII graph could also have disconnected
components with same names referring to the same changeset.
Therefore, given the repo having the 4 changesets (and tags) above, with the
following ASCII graph as input::
foo bar bar foo
| / | |
ancestor(c,d) a baz
The result (`hg log -G -T "{desc}"`) will look like::
o foo
|\
+---o bar
| | |
| o | baz
| /
+---o d
| |
+---o c
| |
o | b
|/
o a
Note that if you take the above `hg log` output directly as input. It will work
as expected - the result would be an isomorphic graph::
o foo
|\
| | o d
| |/
| | o c
| |/
| | o bar
| |/|
| o | b
| |/
o / baz
/
o a
This is because 'o' is specially handled in the input: instead of using 'o' as
the node name, the word to the right will be used.
Some special comments could have side effects:
- Create obsmarkers
# replace: A -> B -> C -> D # chained 1 to 1 replacements
# split: A -> B, C # 1 to many
# prune: A, B, C # many to nothing
"""
from __future__ import absolute_import, print_function
import collections
import itertools
import re
from mercurial.i18n import _
from mercurial import (
context,
error,
node,
obsolete,
pycompat,
registrar,
scmutil,
tags as tagsmod,
)
cmdtable = {}
command = registrar.command(cmdtable)
_pipechars = b'\\/+-|'
_nonpipechars = b''.join(pycompat.bytechr(i) for i in range(33, 127)
if pycompat.bytechr(i) not in _pipechars)
def _isname(ch):
"""char -> bool. return True if ch looks like part of a name, False
otherwise"""
return ch in _nonpipechars
def _parseasciigraph(text):
r"""str -> {str : [str]}. convert the ASCII graph to edges
>>> import pprint
>>> pprint.pprint({pycompat.sysstr(k): [pycompat.sysstr(vv) for vv in v]
... for k, v in _parseasciigraph(br'''
... G
... |
... I D C F # split: B -> E, F, G
... \ \| | # replace: C -> D -> H
... H B E # prune: F, I
... \|/
... A
... ''').items()})
{'A': [],
'B': ['A'],
'C': ['B'],
'D': ['B'],
'E': ['A'],
'F': ['E'],
'G': ['F'],
'H': ['A'],
'I': ['H']}
>>> pprint.pprint({pycompat.sysstr(k): [pycompat.sysstr(vv) for vv in v]
... for k, v in _parseasciigraph(br'''
... o foo
... |\
... +---o bar
... | | |
... | o | baz
... | /
... +---o d
... | |
... +---o c
... | |
... o | b
... |/
... o a
... ''').items()})
{'a': [],
'b': ['a'],
'bar': ['b', 'a'],
'baz': [],
'c': ['b'],
'd': ['b'],
'foo': ['baz', 'b']}
"""
lines = text.splitlines()
edges = collections.defaultdict(list) # {node: []}
def get(y, x):
"""(int, int) -> char. give a coordinate, return the char. return a
space for anything out of range"""
if x < 0 or y < 0:
return b' '
try:
return lines[y][x:x + 1] or b' '
except IndexError:
return b' '
def getname(y, x):
"""(int, int) -> str. like get(y, x) but concatenate left and right
parts. if name is an 'o', try to replace it to the right"""
result = b''
for i in itertools.count(0):
ch = get(y, x - i)
if not _isname(ch):
break
result = ch + result
for i in itertools.count(1):
ch = get(y, x + i)
if not _isname(ch):
break
result += ch
if result == b'o':
# special handling, find the name to the right
result = b''
for i in itertools.count(2):
ch = get(y, x + i)
if ch == b' ' or ch in _pipechars:
if result or x + i >= len(lines[y]):
break
else:
result += ch
return result or b'o'
return result
def parents(y, x):
"""(int, int) -> [str]. follow the ASCII edges at given position,
return a list of parents"""
visited = {(y, x)}
visit = []
result = []
def follow(y, x, expected):
"""conditionally append (y, x) to visit array, if it's a char
in excepted. 'o' in expected means an '_isname' test.
if '-' (or '+') is not in excepted, and get(y, x) is '-' (or '+'),
the next line (y + 1, x) will be checked instead."""
ch = get(y, x)
if any(ch == c and c not in expected for c in (b'-', b'+')):
y += 1
return follow(y + 1, x, expected)
if ch in expected or (b'o' in expected and _isname(ch)):
visit.append((y, x))
# -o- # starting point:
# /|\ # follow '-' (horizontally), and '/|\' (to the bottom)
follow(y + 1, x, b'|')
follow(y + 1, x - 1, b'/')
follow(y + 1, x + 1, b'\\')
follow(y, x - 1, b'-')
follow(y, x + 1, b'-')
while visit:
y, x = visit.pop()
if (y, x) in visited:
continue
visited.add((y, x))
ch = get(y, x)
if _isname(ch):
result.append(getname(y, x))
continue
elif ch == b'|':
follow(y + 1, x, b'/|o')
follow(y + 1, x - 1, b'/')
follow(y + 1, x + 1, b'\\')
elif ch == b'+':
follow(y, x - 1, b'-')
follow(y, x + 1, b'-')
follow(y + 1, x - 1, b'/')
follow(y + 1, x + 1, b'\\')
follow(y + 1, x, b'|')
elif ch == b'\\':
follow(y + 1, x + 1, b'\\|o')
elif ch == b'/':
follow(y + 1, x - 1, b'/|o')
elif ch == b'-':
follow(y, x - 1, b'-+o')
follow(y, x + 1, b'-+o')
return result
for y, line in enumerate(lines):
for x, ch in enumerate(pycompat.bytestr(line)):
if ch == b'#': # comment
break
if _isname(ch):
edges[getname(y, x)] += parents(y, x)
return dict(edges)
class simplefilectx(object):
def __init__(self, path, data):
self._data = data
self._path = path
def data(self):
return self._data
def filenode(self):
return None
def path(self):
return self._path
def copysource(self):
return None
def flags(self):
return b''
class simplecommitctx(context.committablectx):
def __init__(self, repo, name, parentctxs, added):
opts = {
'changes': scmutil.status([], list(added), [], [], [], [], []),
'date': b'0 0',
'extra': {b'branch': b'default'},
}
super(simplecommitctx, self).__init__(repo, name, **opts)
self._added = added
self._parents = parentctxs
while len(self._parents) < 2:
self._parents.append(repo[node.nullid])
def filectx(self, key):
return simplefilectx(key, self._added[key])
def commit(self):
return self._repo.commitctx(self)
def p1copies(self):
return {}
def p2copies(self):
return {}
def _walkgraph(edges):
"""yield node, parents in topologically order"""
visible = set(edges.keys())
remaining = {} # {str: [str]}
for k, vs in edges.items():
for v in vs:
if v not in remaining:
remaining[v] = []
remaining[k] = vs[:]
while remaining:
leafs = [k for k, v in remaining.items() if not v]
if not leafs:
raise error.Abort(_('the graph has cycles'))
for leaf in sorted(leafs):
if leaf in visible:
yield leaf, edges[leaf]
del remaining[leaf]
for k, v in remaining.items():
if leaf in v:
v.remove(leaf)
def _getcomments(text):
r"""
>>> [pycompat.sysstr(s) for s in _getcomments(br'''
... G
... |
... I D C F # split: B -> E, F, G
... \ \| | # replace: C -> D -> H
... H B E # prune: F, I
... \|/
... A
... ''')]
['split: B -> E, F, G', 'replace: C -> D -> H', 'prune: F, I']
"""
for line in text.splitlines():
if b' # ' not in line:
continue
yield line.split(b' # ', 1)[1].split(b' # ')[0].strip()
@command(b'debugdrawdag', [])
def debugdrawdag(ui, repo, **opts):
r"""read an ASCII graph from stdin and create changesets
The ASCII graph is like what :hg:`log -G` outputs, with each `o` replaced
to the name of the node. The command will create dummy changesets and local
tags with those names to make the dummy changesets easier to be referred
to.
If the name of a node is a single character 'o', It will be replaced by the
word to the right. This makes it easier to reuse
:hg:`log -G -T '{desc}'` outputs.
For root (no parents) nodes, revset can be used to query existing repo.
Note that the revset cannot have confusing characters which can be seen as
the part of the graph edges, like `|/+-\`.
"""
text = ui.fin.read()
# parse the graph and make sure len(parents) <= 2 for each node
edges = _parseasciigraph(text)
for k, v in edges.items():
if len(v) > 2:
raise error.Abort(_('%s: too many parents: %s')
% (k, b' '.join(v)))
# parse comments to get extra file content instructions
files = collections.defaultdict(dict) # {(name, path): content}
comments = list(_getcomments(text))
filere = re.compile(br'^(\w+)/([\w/]+)\s*=\s*(.*)$', re.M)
for name, path, content in filere.findall(b'\n'.join(comments)):
content = content.replace(br'\n', b'\n').replace(br'\1', b'\1')
files[name][path] = content
committed = {None: node.nullid} # {name: node}
# for leaf nodes, try to find existing nodes in repo
for name, parents in edges.items():
if len(parents) == 0:
try:
committed[name] = scmutil.revsingle(repo, name)
except error.RepoLookupError:
pass
# commit in topological order
for name, parents in _walkgraph(edges):
if name in committed:
continue
pctxs = [repo[committed[n]] for n in parents]
pctxs.sort(key=lambda c: c.node())
added = {}
if len(parents) > 1:
# If it's a merge, take the files and contents from the parents
for f in pctxs[1].manifest():
if f not in pctxs[0].manifest():
added[f] = pctxs[1][f].data()
else:
# If it's not a merge, add a single file
added[name] = name
# add extra file contents in comments
for path, content in files.get(name, {}).items():
added[path] = content
ctx = simplecommitctx(repo, name, pctxs, added)
n = ctx.commit()
committed[name] = n
tagsmod.tag(repo, [name], n, message=None, user=None, date=None,
local=True)
# handle special comments
with repo.wlock(), repo.lock(), repo.transaction(b'drawdag'):
getctx = lambda x: repo.unfiltered()[committed[x.strip()]]
for comment in comments:
rels = [] # obsolete relationships
args = comment.split(b':', 1)
if len(args) <= 1:
continue
cmd = args[0].strip()
arg = args[1].strip()
if cmd in (b'replace', b'rebase', b'amend'):
nodes = [getctx(m) for m in arg.split(b'->')]
for i in range(len(nodes) - 1):
rels.append((nodes[i], (nodes[i + 1],)))
elif cmd in (b'split',):
pre, succs = arg.split(b'->')
succs = succs.split(b',')
rels.append((getctx(pre), (getctx(s) for s in succs)))
elif cmd in (b'prune',):
for n in arg.split(b','):
rels.append((getctx(n), ()))
if rels:
obsolete.createmarkers(repo, rels, date=(0, 0), operation=cmd)