rebase: add boolean config item rebase.store-source
This allows to use rebase without recording a rebase_source extra
field. This is useful for example to build a mirror converted from
another SCM (such as svn) by converting only new revisions, and
then incrementally add them to the destination by pulling from the
newly converted (unrelated) repo and rebasing the new revisions
onto the last old already stored changeset. Without this patch the
rebased changesets would always receive some rebase_source that
would depend on the particular history of the conversion process,
instead of only depending on the original source revisions.
This is used to implement a hg mirror repo of SvarDOS (a partially
nonfree but completely redistributable DOS distribution) in the
scripts at https://hg.pushbx.org/ecm/svardos.scr/
In particular, cre.sh creates an svn mirror, upd.sh recreates an
entire hg repo from the svn mirror (which takes too long to do in a
regular job), and akt.sh uses hg convert with the config item
convert.svn.startrev to incrementally convert only the two most
recent revisions already found in the mirror destination plus any
possible new revisions. If any are found, the temporary repo's
changesets are pulled into the destination (as changesets from an
unrelated repository). Then the changesets corresponding to the new
revisions are rebased onto the prior final changeset. (Finally, the
two remaining duplicates of the prior head and its parent are
stripped from the destination repository.)
Without this patch, the particular rebase_source extra field would
depend on the order and times at which akt.sh was used, instead of
only depending on the source repository. In other words, whatever
sequence of upd.sh and akt.sh is used at whatever times, it is
desired that the final output repositories always match each other
exactly.
# 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 .i18n import _
from . import (
error,
mdiff,
)
from .utils import stringutil
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(range(astart, aend), range(bstart, bend)):
if a[ia] != b[ib]:
return False
else:
return True
class Merge3Text:
"""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_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 == b'unchanged':
yield what, self.base[t[1] : t[2]]
elif what == b'a' or what == b'same':
yield what, self.a[t[1] : t[2]]
elif what == b'b':
yield what, self.b[t[1] : t[2]]
elif what == b'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 b'same', ia, amatch
elif equal_a and not equal_b:
yield b'b', ib, bmatch
elif equal_b and not equal_a:
yield b'a', ia, amatch
elif not equal_a and not equal_b:
yield b'conflict', iz, zmatch, ia, amatch, ib, bmatch
else:
raise AssertionError(b"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 b'unchanged', zmatch, zend
iz = zend
ia = aend
ib = bend
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 _verifytext(input):
"""verifies that text is non-binary (unless opts[text] is passed,
then we just warn)"""
if stringutil.binary(input.text()):
msg = _(b"%s looks like a binary file.") % input.fctx.path()
raise error.Abort(msg)
def _format_labels(*inputs):
pad = max(len(input.label) if input.label else 0 for input in inputs)
labels = []
for input in inputs:
if input.label:
if input.label_detail:
label = (
(input.label + b':').ljust(pad + 1)
+ b' '
+ input.label_detail
)
else:
label = input.label
# 8 for the prefix of conflict marker lines (e.g. '<<<<<<< ')
labels.append(stringutil.ellipsis(label, 80 - 8))
else:
labels.append(None)
return labels
def _detect_newline(m3):
if len(m3.a) > 0:
if m3.a[0].endswith(b'\r\n'):
return b'\r\n'
elif m3.a[0].endswith(b'\r'):
return b'\r'
return b'\n'
def _minimize(a_lines, b_lines):
"""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.
"""
alen = len(a_lines)
blen = len(b_lines)
# find matches at the front
ii = 0
while ii < alen and ii < blen and a_lines[ii] == b_lines[ii]:
ii += 1
startmatches = ii
# find matches at the end
ii = 0
while ii < alen and ii < blen and a_lines[-ii - 1] == b_lines[-ii - 1]:
ii += 1
endmatches = ii
lines_before = a_lines[:startmatches]
new_a_lines = a_lines[startmatches : alen - endmatches]
new_b_lines = b_lines[startmatches : blen - endmatches]
lines_after = a_lines[alen - endmatches :]
return lines_before, new_a_lines, new_b_lines, lines_after
def render_minimized(
m3,
name_a=None,
name_b=None,
start_marker=b'<<<<<<<',
mid_marker=b'=======',
end_marker=b'>>>>>>>',
):
"""Return merge in cvs-like form."""
newline = _detect_newline(m3)
conflicts = False
if name_a:
start_marker = start_marker + b' ' + name_a
if name_b:
end_marker = end_marker + b' ' + name_b
merge_groups = m3.merge_groups()
lines = []
for what, group_lines in merge_groups:
if what == b'conflict':
conflicts = True
base_lines, a_lines, b_lines = group_lines
minimized = _minimize(a_lines, b_lines)
lines_before, a_lines, b_lines, lines_after = minimized
lines.extend(lines_before)
lines.append(start_marker + newline)
lines.extend(a_lines)
lines.append(mid_marker + newline)
lines.extend(b_lines)
lines.append(end_marker + newline)
lines.extend(lines_after)
else:
lines.extend(group_lines)
return lines, conflicts
def render_merge3(m3, name_a, name_b, name_base):
"""Render conflicts as 3-way conflict markers."""
newline = _detect_newline(m3)
conflicts = False
lines = []
for what, group_lines in m3.merge_groups():
if what == b'conflict':
base_lines, a_lines, b_lines = group_lines
conflicts = True
lines.append(b'<<<<<<< ' + name_a + newline)
lines.extend(a_lines)
lines.append(b'||||||| ' + name_base + newline)
lines.extend(base_lines)
lines.append(b'=======' + newline)
lines.extend(b_lines)
lines.append(b'>>>>>>> ' + name_b + newline)
else:
lines.extend(group_lines)
return lines, conflicts
def render_mergediff(m3, name_a, name_b, name_base):
"""Render conflicts as conflict markers with one snapshot and one diff."""
newline = _detect_newline(m3)
lines = []
conflicts = False
for what, group_lines in m3.merge_groups():
if what == b'conflict':
base_lines, a_lines, b_lines = group_lines
base_text = b''.join(base_lines)
b_blocks = list(
mdiff.allblocks(
base_text,
b''.join(b_lines),
lines1=base_lines,
lines2=b_lines,
)
)
a_blocks = list(
mdiff.allblocks(
base_text,
b''.join(a_lines),
lines1=base_lines,
lines2=b_lines,
)
)
def matching_lines(blocks):
return sum(
block[1] - block[0]
for block, kind in blocks
if kind == b'='
)
def diff_lines(blocks, lines1, lines2):
for block, kind in blocks:
if kind == b'=':
for line in lines1[block[0] : block[1]]:
yield b' ' + line
else:
for line in lines1[block[0] : block[1]]:
yield b'-' + line
for line in lines2[block[2] : block[3]]:
yield b'+' + line
lines.append(b"<<<<<<<" + newline)
if matching_lines(a_blocks) < matching_lines(b_blocks):
lines.append(b"======= " + name_a + newline)
lines.extend(a_lines)
lines.append(b"------- " + name_base + newline)
lines.append(b"+++++++ " + name_b + newline)
lines.extend(diff_lines(b_blocks, base_lines, b_lines))
else:
lines.append(b"------- " + name_base + newline)
lines.append(b"+++++++ " + name_a + newline)
lines.extend(diff_lines(a_blocks, base_lines, a_lines))
lines.append(b"======= " + name_b + newline)
lines.extend(b_lines)
lines.append(b">>>>>>>" + newline)
conflicts = True
else:
lines.extend(group_lines)
return lines, conflicts
def _resolve(m3, sides):
lines = []
for what, group_lines in m3.merge_groups():
if what == b'conflict':
for side in sides:
lines.extend(group_lines[side])
else:
lines.extend(group_lines)
return lines
class MergeInput:
def __init__(self, fctx, label=None, label_detail=None):
self.fctx = fctx
self.label = label
# If the "detail" part is set, then that is rendered after the label and
# separated by a ':'. The label is padded to make the ':' aligned among
# all merge inputs.
self.label_detail = label_detail
self._text = None
def text(self):
if self._text is None:
# 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.
self._text = self.fctx.decodeddata()
return self._text
def set_text(self, text):
self._text = text
def simplemerge(
local,
base,
other,
mode=b'merge',
allow_binary=False,
):
"""Performs the simplemerge algorithm.
The merged result is written into `localctx`.
"""
if not allow_binary:
_verifytext(local)
_verifytext(base)
_verifytext(other)
m3 = Merge3Text(base.text(), local.text(), other.text())
conflicts = False
if mode == b'union':
lines = _resolve(m3, (1, 2))
elif mode == b'local':
lines = _resolve(m3, (1,))
elif mode == b'other':
lines = _resolve(m3, (2,))
else:
if mode == b'mergediff':
labels = _format_labels(local, other, base)
lines, conflicts = render_mergediff(m3, *labels)
elif mode == b'merge3':
labels = _format_labels(local, other, base)
lines, conflicts = render_merge3(m3, *labels)
else:
labels = _format_labels(local, other)
lines, conflicts = render_minimized(m3, *labels)
mergedtext = b''.join(lines)
return mergedtext, conflicts