debugcommands: add debugwireproto command
We currently don't have a low-level mechanism for sending
arbitrary wire protocol commands. Having a generic and robust
mechanism for sending wire protocol commands, examining wire
data, etc would make it vastly easier to test the wire protocol
and debug server operation. This is a problem I've wanted a
solution for numerous times, especially recently as I've been
hacking on a new version of the wire protocol.
This commit establishes a `hg debugwireproto` command for sending
data to a peer.
The command invents a mini language for specifying actions to take.
This will enable a lot of flexibility for issuing commands and testing
variations for how commands are sent.
Right now, we only support low-level raw sends and receives. These
are probably the least valuable commands to intended users of this
command. But they are the most useful commands to implement to
bootstrap the feature (I've chosen to reimplement test-ssh-proto.t
using this command to prove its usefulness).
My eventual goal of `hg debugwireproto` is to allow calling wire
protocol commands with a human-friendly interface. Essentially,
people can type in a command name and arguments and
`hg debugwireproto` will figure out how to send that on the wire.
I'd love to eventually be able to save the server's raw response
to a file. This would allow us to e.g. call "getbundle" wire
protocol commands easily.
test-ssh-proto.t has been updated to use the new command in lieu
of piping directly to a server process. As part of the transition,
test behavior improved. Before, we piped all request data to the
server at once. Now, we have explicit control over the ordering of
operations. e.g. we can send one command, receive its response,
then send another command. This will allow us to more robustly
test race conditions, buffering behavior, etc.
There were some subtle changes in test behavior. For example,
previous behavior would often send trailing newlines to the server.
The new mechanism doesn't treat literal newlines specially and
requires newlines be escaped in the payload.
Because the new logging code is very low level, it is easy to
introduce race conditions in tests. For example, the number of bytes
returned by a read() may vary depending on load. This is why tests
make heavy use of "readline" for consuming data: the result of
that operation should be deterministic and not subject to race
conditions. There are still some uses of "readavailable." However,
those are only for reading from stderr. I was able to reproduce
timing issues with my system under load when using "readavailable"
globally. But if I "readline" to grab stdout, "readavailable"
appears to work deterministically for stderr. I think this is
because the server writes to stderr first. As long as the OS
delivers writes to pipes in the same order they were made, this
should work. If there are timing issues, we can introduce a
mechanism to readline from stderr.
Differential Revision: https://phab.mercurial-scm.org/D2392
# Copyright (C) 2004, 2005 Canonical Ltd
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, see <http://www.gnu.org/licenses/>.
# mbp: "you know that thing where cvs gives you conflict markers?"
# s: "i hate that."
from __future__ import absolute_import
from .i18n import _
from . import (
error,
mdiff,
pycompat,
util,
)
class CantReprocessAndShowBase(Exception):
pass
def intersect(ra, rb):
"""Given two ranges return the range where they intersect or None.
>>> intersect((0, 10), (0, 6))
(0, 6)
>>> intersect((0, 10), (5, 15))
(5, 10)
>>> intersect((0, 10), (10, 15))
>>> intersect((0, 9), (10, 15))
>>> intersect((0, 9), (7, 15))
(7, 9)
"""
assert ra[0] <= ra[1]
assert rb[0] <= rb[1]
sa = max(ra[0], rb[0])
sb = min(ra[1], rb[1])
if sa < sb:
return sa, sb
else:
return None
def compare_range(a, astart, aend, b, bstart, bend):
"""Compare a[astart:aend] == b[bstart:bend], without slicing.
"""
if (aend - astart) != (bend - bstart):
return False
for ia, ib in zip(xrange(astart, aend), xrange(bstart, bend)):
if a[ia] != b[ib]:
return False
else:
return True
class Merge3Text(object):
"""3-way merge of texts.
Given strings BASE, OTHER, THIS, tries to produce a combined text
incorporating the changes from both BASE->OTHER and BASE->THIS."""
def __init__(self, basetext, atext, btext, base=None, a=None, b=None):
self.basetext = basetext
self.atext = atext
self.btext = btext
if base is None:
base = mdiff.splitnewlines(basetext)
if a is None:
a = mdiff.splitnewlines(atext)
if b is None:
b = mdiff.splitnewlines(btext)
self.base = base
self.a = a
self.b = b
def merge_lines(self,
name_a=None,
name_b=None,
name_base=None,
start_marker='<<<<<<<',
mid_marker='=======',
end_marker='>>>>>>>',
base_marker=None,
localorother=None,
minimize=False):
"""Return merge in cvs-like form.
"""
self.conflicts = False
newline = '\n'
if len(self.a) > 0:
if self.a[0].endswith('\r\n'):
newline = '\r\n'
elif self.a[0].endswith('\r'):
newline = '\r'
if name_a and start_marker:
start_marker = start_marker + ' ' + name_a
if name_b and end_marker:
end_marker = end_marker + ' ' + name_b
if name_base and base_marker:
base_marker = base_marker + ' ' + name_base
merge_regions = self.merge_regions()
if minimize:
merge_regions = self.minimize(merge_regions)
for t in merge_regions:
what = t[0]
if what == 'unchanged':
for i in range(t[1], t[2]):
yield self.base[i]
elif what == 'a' or what == 'same':
for i in range(t[1], t[2]):
yield self.a[i]
elif what == 'b':
for i in range(t[1], t[2]):
yield self.b[i]
elif what == 'conflict':
if localorother == 'local':
for i in range(t[3], t[4]):
yield self.a[i]
elif localorother == 'other':
for i in range(t[5], t[6]):
yield self.b[i]
else:
self.conflicts = True
if start_marker is not None:
yield start_marker + newline
for i in range(t[3], t[4]):
yield self.a[i]
if base_marker is not None:
yield base_marker + newline
for i in range(t[1], t[2]):
yield self.base[i]
if mid_marker is not None:
yield mid_marker + newline
for i in range(t[5], t[6]):
yield self.b[i]
if end_marker is not None:
yield end_marker + newline
else:
raise ValueError(what)
def merge_groups(self):
"""Yield sequence of line groups. Each one is a tuple:
'unchanged', lines
Lines unchanged from base
'a', lines
Lines taken from a
'same', lines
Lines taken from a (and equal to b)
'b', lines
Lines taken from b
'conflict', base_lines, a_lines, b_lines
Lines from base were changed to either a or b and conflict.
"""
for t in self.merge_regions():
what = t[0]
if what == 'unchanged':
yield what, self.base[t[1]:t[2]]
elif what == 'a' or what == 'same':
yield what, self.a[t[1]:t[2]]
elif what == 'b':
yield what, self.b[t[1]:t[2]]
elif what == 'conflict':
yield (what,
self.base[t[1]:t[2]],
self.a[t[3]:t[4]],
self.b[t[5]:t[6]])
else:
raise ValueError(what)
def merge_regions(self):
"""Return sequences of matching and conflicting regions.
This returns tuples, where the first value says what kind we
have:
'unchanged', start, end
Take a region of base[start:end]
'same', astart, aend
b and a are different from base but give the same result
'a', start, end
Non-clashing insertion from a[start:end]
'conflict', zstart, zend, astart, aend, bstart, bend
Conflict between a and b, with z as common ancestor
Method is as follows:
The two sequences align only on regions which match the base
and both descendants. These are found by doing a two-way diff
of each one against the base, and then finding the
intersections between those regions. These "sync regions"
are by definition unchanged in both and easily dealt with.
The regions in between can be in any of three cases:
conflicted, or changed on only one side.
"""
# section a[0:ia] has been disposed of, etc
iz = ia = ib = 0
for region in self.find_sync_regions():
zmatch, zend, amatch, aend, bmatch, bend = region
#print 'match base [%d:%d]' % (zmatch, zend)
matchlen = zend - zmatch
assert matchlen >= 0
assert matchlen == (aend - amatch)
assert matchlen == (bend - bmatch)
len_a = amatch - ia
len_b = bmatch - ib
len_base = zmatch - iz
assert len_a >= 0
assert len_b >= 0
assert len_base >= 0
#print 'unmatched a=%d, b=%d' % (len_a, len_b)
if len_a or len_b:
# try to avoid actually slicing the lists
equal_a = compare_range(self.a, ia, amatch,
self.base, iz, zmatch)
equal_b = compare_range(self.b, ib, bmatch,
self.base, iz, zmatch)
same = compare_range(self.a, ia, amatch,
self.b, ib, bmatch)
if same:
yield 'same', ia, amatch
elif equal_a and not equal_b:
yield 'b', ib, bmatch
elif equal_b and not equal_a:
yield 'a', ia, amatch
elif not equal_a and not equal_b:
yield 'conflict', iz, zmatch, ia, amatch, ib, bmatch
else:
raise AssertionError("can't handle a=b=base but unmatched")
ia = amatch
ib = bmatch
iz = zmatch
# if the same part of the base was deleted on both sides
# that's OK, we can just skip it.
if matchlen > 0:
assert ia == amatch
assert ib == bmatch
assert iz == zmatch
yield 'unchanged', zmatch, zend
iz = zend
ia = aend
ib = bend
def minimize(self, merge_regions):
"""Trim conflict regions of lines where A and B sides match.
Lines where both A and B have made the same changes at the beginning
or the end of each merge region are eliminated from the conflict
region and are instead considered the same.
"""
for region in merge_regions:
if region[0] != "conflict":
yield region
continue
issue, z1, z2, a1, a2, b1, b2 = region
alen = a2 - a1
blen = b2 - b1
# find matches at the front
ii = 0
while ii < alen and ii < blen and \
self.a[a1 + ii] == self.b[b1 + ii]:
ii += 1
startmatches = ii
# find matches at the end
ii = 0
while ii < alen and ii < blen and \
self.a[a2 - ii - 1] == self.b[b2 - ii - 1]:
ii += 1
endmatches = ii
if startmatches > 0:
yield 'same', a1, a1 + startmatches
yield ('conflict', z1, z2,
a1 + startmatches, a2 - endmatches,
b1 + startmatches, b2 - endmatches)
if endmatches > 0:
yield 'same', a2 - endmatches, a2
def find_sync_regions(self):
"""Return a list of sync regions, where both descendants match the base.
Generates a list of (base1, base2, a1, a2, b1, b2). There is
always a zero-length sync region at the end of all the files.
"""
ia = ib = 0
amatches = mdiff.get_matching_blocks(self.basetext, self.atext)
bmatches = mdiff.get_matching_blocks(self.basetext, self.btext)
len_a = len(amatches)
len_b = len(bmatches)
sl = []
while ia < len_a and ib < len_b:
abase, amatch, alen = amatches[ia]
bbase, bmatch, blen = bmatches[ib]
# there is an unconflicted block at i; how long does it
# extend? until whichever one ends earlier.
i = intersect((abase, abase + alen), (bbase, bbase + blen))
if i:
intbase = i[0]
intend = i[1]
intlen = intend - intbase
# found a match of base[i[0], i[1]]; this may be less than
# the region that matches in either one
assert intlen <= alen
assert intlen <= blen
assert abase <= intbase
assert bbase <= intbase
asub = amatch + (intbase - abase)
bsub = bmatch + (intbase - bbase)
aend = asub + intlen
bend = bsub + intlen
assert self.base[intbase:intend] == self.a[asub:aend], \
(self.base[intbase:intend], self.a[asub:aend])
assert self.base[intbase:intend] == self.b[bsub:bend]
sl.append((intbase, intend,
asub, aend,
bsub, bend))
# advance whichever one ends first in the base text
if (abase + alen) < (bbase + blen):
ia += 1
else:
ib += 1
intbase = len(self.base)
abase = len(self.a)
bbase = len(self.b)
sl.append((intbase, intbase, abase, abase, bbase, bbase))
return sl
def find_unconflicted(self):
"""Return a list of ranges in base that are not conflicted."""
am = mdiff.get_matching_blocks(self.basetext, self.atext)
bm = mdiff.get_matching_blocks(self.basetext, self.btext)
unc = []
while am and bm:
# there is an unconflicted block at i; how long does it
# extend? until whichever one ends earlier.
a1 = am[0][0]
a2 = a1 + am[0][2]
b1 = bm[0][0]
b2 = b1 + bm[0][2]
i = intersect((a1, a2), (b1, b2))
if i:
unc.append(i)
if a2 < b2:
del am[0]
else:
del bm[0]
return unc
def _verifytext(text, path, ui, opts):
"""verifies that text is non-binary (unless opts[text] is passed,
then we just warn)"""
if util.binary(text):
msg = _("%s looks like a binary file.") % path
if not opts.get('quiet'):
ui.warn(_('warning: %s\n') % msg)
if not opts.get('text'):
raise error.Abort(msg)
return text
def _picklabels(defaults, overrides):
if len(overrides) > 3:
raise error.Abort(_("can only specify three labels."))
result = defaults[:]
for i, override in enumerate(overrides):
result[i] = override
return result
def simplemerge(ui, localctx, basectx, otherctx, **opts):
"""Performs the simplemerge algorithm.
The merged result is written into `localctx`.
"""
opts = pycompat.byteskwargs(opts)
def readctx(ctx):
# Merges were always run in the working copy before, which means
# they used decoded data, if the user defined any repository
# filters.
#
# Maintain that behavior today for BC, though perhaps in the future
# it'd be worth considering whether merging encoded data (what the
# repository usually sees) might be more useful.
return _verifytext(ctx.decodeddata(), ctx.path(), ui, opts)
mode = opts.get('mode','merge')
name_a, name_b, name_base = None, None, None
if mode != 'union':
name_a, name_b, name_base = _picklabels([localctx.path(),
otherctx.path(), None],
opts.get('label', []))
try:
localtext = readctx(localctx)
basetext = readctx(basectx)
othertext = readctx(otherctx)
except error.Abort:
return 1
m3 = Merge3Text(basetext, localtext, othertext)
extrakwargs = {
"localorother": opts.get("localorother", None),
'minimize': True,
}
if mode == 'union':
extrakwargs['start_marker'] = None
extrakwargs['mid_marker'] = None
extrakwargs['end_marker'] = None
elif name_base is not None:
extrakwargs['base_marker'] = '|||||||'
extrakwargs['name_base'] = name_base
extrakwargs['minimize'] = False
mergedtext = ""
for line in m3.merge_lines(name_a=name_a, name_b=name_b,
**pycompat.strkwargs(extrakwargs)):
if opts.get('print'):
ui.fout.write(line)
else:
mergedtext += line
if not opts.get('print'):
localctx.write(mergedtext, localctx.flags())
if m3.conflicts and not mode == 'union':
return 1