/usr/lib/python2.7/dist-packages/bzrlib/plugins/changelog_merge/changelog_merge.py is in python-bzrlib 2.7.0-2ubuntu3.1.
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The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 | # Copyright (C) 2010 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, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
"""Merge logic for changelog_merge plugin."""
from __future__ import absolute_import
import difflib
from bzrlib import (
debug,
merge,
urlutils,
)
from bzrlib.merge3 import Merge3
from bzrlib.trace import mutter
def changelog_entries(lines):
"""Return a list of changelog entries.
:param lines: lines of a changelog file.
:returns: list of entries. Each entry is a tuple of lines.
"""
entries = []
for line in lines:
if line[0] not in (' ', '\t', '\n'):
# new entry
entries.append([line])
else:
try:
entry = entries[-1]
except IndexError:
# Cope with leading blank lines.
entries.append([])
entry = entries[-1]
entry.append(line)
return map(tuple, entries)
def entries_to_lines(entries):
"""Turn a list of entries into a flat iterable of lines."""
for entry in entries:
for line in entry:
yield line
class ChangeLogMerger(merge.ConfigurableFileMerger):
"""Merge GNU-format ChangeLog files."""
name_prefix = "changelog"
def get_filepath(self, params, tree):
"""Calculate the path to the file in a tree.
This is overridden to return just the basename, rather than full path,
so that e.g. if the config says ``changelog_merge_files = ChangeLog``,
then all ChangeLog files in the tree will match (not just one in the
root of the tree).
:param params: A MergeHookParams describing the file to merge
:param tree: a Tree, e.g. self.merger.this_tree.
"""
return urlutils.basename(tree.id2path(params.file_id))
def merge_text(self, params):
"""Merge changelog changes.
* new entries from other will float to the top
* edits to older entries are preserved
"""
# Transform files into lists of changelog entries
this_entries = changelog_entries(params.this_lines)
other_entries = changelog_entries(params.other_lines)
base_entries = changelog_entries(params.base_lines)
try:
result_entries = merge_entries(
base_entries, this_entries, other_entries)
except EntryConflict:
# XXX: generating a nice conflict file would be better
return 'not_applicable', None
# Transform the merged elements back into real blocks of lines.
return 'success', entries_to_lines(result_entries)
class EntryConflict(Exception):
pass
def default_guess_edits(new_entries, deleted_entries, entry_as_str=''.join):
"""Default implementation of guess_edits param of merge_entries.
This algorithm does O(N^2 * logN) SequenceMatcher.ratio() calls, which is
pretty bad, but it shouldn't be used very often.
"""
deleted_entries_as_strs = map(entry_as_str, deleted_entries)
new_entries_as_strs = map(entry_as_str, new_entries)
result_new = list(new_entries)
result_deleted = list(deleted_entries)
result_edits = []
sm = difflib.SequenceMatcher()
CUTOFF = 0.8
while True:
best = None
best_score = CUTOFF
# Compare each new entry with each old entry to find the best match
for new_entry_as_str in new_entries_as_strs:
sm.set_seq1(new_entry_as_str)
for old_entry_as_str in deleted_entries_as_strs:
sm.set_seq2(old_entry_as_str)
score = sm.ratio()
if score > best_score:
best = new_entry_as_str, old_entry_as_str
best_score = score
if best is not None:
# Add the best match to the list of edits, and remove it from the
# the list of new/old entries. Also remove it from the new/old
# lists for the next round.
del_index = deleted_entries_as_strs.index(best[1])
new_index = new_entries_as_strs.index(best[0])
result_edits.append(
(result_deleted[del_index], result_new[new_index]))
del deleted_entries_as_strs[del_index], result_deleted[del_index]
del new_entries_as_strs[new_index], result_new[new_index]
else:
# No match better than CUTOFF exists in the remaining new and old
# entries.
break
return result_new, result_deleted, result_edits
def merge_entries(base_entries, this_entries, other_entries,
guess_edits=default_guess_edits):
"""Merge changelog given base, this, and other versions."""
m3 = Merge3(base_entries, this_entries, other_entries, allow_objects=True)
result_entries = []
at_top = True
for group in m3.merge_groups():
if 'changelog_merge' in debug.debug_flags:
mutter('merge group:\n%r', group)
group_kind = group[0]
if group_kind == 'conflict':
_, base, this, other = group
# Find additions
new_in_other = [
entry for entry in other if entry not in base]
# Find deletions
deleted_in_other = [
entry for entry in base if entry not in other]
if at_top and deleted_in_other:
# Magic! Compare deletions and additions to try spot edits
new_in_other, deleted_in_other, edits_in_other = guess_edits(
new_in_other, deleted_in_other)
else:
# Changes not made at the top are always preserved as is, no
# need to try distinguish edits from adds and deletes.
edits_in_other = []
if 'changelog_merge' in debug.debug_flags:
mutter('at_top: %r', at_top)
mutter('new_in_other: %r', new_in_other)
mutter('deleted_in_other: %r', deleted_in_other)
mutter('edits_in_other: %r', edits_in_other)
# Apply deletes and edits
updated_this = [
entry for entry in this if entry not in deleted_in_other]
for old_entry, new_entry in edits_in_other:
try:
index = updated_this.index(old_entry)
except ValueError:
# edited entry no longer present in this! Just give up and
# declare a conflict.
raise EntryConflict()
updated_this[index] = new_entry
if 'changelog_merge' in debug.debug_flags:
mutter('updated_this: %r', updated_this)
if at_top:
# Float new entries from other to the top
result_entries = new_in_other + result_entries
else:
result_entries.extend(new_in_other)
result_entries.extend(updated_this)
else: # unchanged, same, a, or b.
lines = group[1]
result_entries.extend(lines)
at_top = False
return result_entries
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