mdiff/patch: fix bad hunk handling for unified diffs with zero context
Prior to this patch "hg diff -U0", i.e., zero lines of context, would
output hunk headers with a start line one greater than what GNU patch
and git output. Guido van Rossum documents the unified diff format[1]
as having a start line value "one lower than one would expect" for
zero length hunks.
Comparing the behaviour of the three systems prior to this patch in
transforming
c1
c3
to
c1
c2
c3
- GNU "diff -U0" reports the hunk as "@@ -1,0 +2 @@"
- "git diff -U0" reports the hunk as "@@ -1,0 +2 @@"
- "hg diff -U0" reports the hunk as "@@ -2,0 +2,1 @@"
After this patch, "hg diff -U0" reports "@@ -1,0 +2,1 @@".
Since "hg export --config diff.unified=0" outputs zero-context unified
diffs, "hg import" has also been updated to account for start lines
one less than expected for zero length hunk ranges.
[1]: http://www.artima.com/weblogs/viewpost.jsp?thread=164293
# config.py - configuration parsing for Mercurial
#
# Copyright 2009 Matt Mackall <mpm@selenic.com> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from i18n import _
import error, util
import re, os, errno
class sortdict(dict):
'a simple sorted dictionary'
def __init__(self, data=None):
self._list = []
if data:
self.update(data)
def copy(self):
return sortdict(self)
def __setitem__(self, key, val):
if key in self:
self._list.remove(key)
self._list.append(key)
dict.__setitem__(self, key, val)
def __iter__(self):
return self._list.__iter__()
def update(self, src):
for k in src:
self[k] = src[k]
def clear(self):
dict.clear(self)
self._list = []
def items(self):
return [(k, self[k]) for k in self._list]
def __delitem__(self, key):
dict.__delitem__(self, key)
self._list.remove(key)
class config(object):
def __init__(self, data=None):
self._data = {}
self._source = {}
if data:
for k in data._data:
self._data[k] = data[k].copy()
self._source = data._source.copy()
def copy(self):
return config(self)
def __contains__(self, section):
return section in self._data
def __getitem__(self, section):
return self._data.get(section, {})
def __iter__(self):
for d in self.sections():
yield d
def update(self, src):
for s in src:
if s not in self:
self._data[s] = sortdict()
self._data[s].update(src._data[s])
self._source.update(src._source)
def get(self, section, item, default=None):
return self._data.get(section, {}).get(item, default)
def source(self, section, item):
return self._source.get((section, item), "")
def sections(self):
return sorted(self._data.keys())
def items(self, section):
return self._data.get(section, {}).items()
def set(self, section, item, value, source=""):
if section not in self:
self._data[section] = sortdict()
self._data[section][item] = value
self._source[(section, item)] = source
def parse(self, src, data, sections=None, remap=None, include=None):
sectionre = re.compile(r'\[([^\[]+)\]')
itemre = re.compile(r'([^=\s][^=]*?)\s*=\s*(.*\S|)')
contre = re.compile(r'\s+(\S|\S.*\S)\s*$')
emptyre = re.compile(r'(;|#|\s*$)')
commentre = re.compile(r'(;|#)')
unsetre = re.compile(r'%unset\s+(\S+)')
includere = re.compile(r'%include\s+(\S|\S.*\S)\s*$')
section = ""
item = None
line = 0
cont = False
for l in data.splitlines(True):
line += 1
if cont:
if commentre.match(l):
continue
m = contre.match(l)
if m:
if sections and section not in sections:
continue
v = self.get(section, item) + "\n" + m.group(1)
self.set(section, item, v, "%s:%d" % (src, line))
continue
item = None
cont = False
m = includere.match(l)
if m:
inc = util.expandpath(m.group(1))
base = os.path.dirname(src)
inc = os.path.normpath(os.path.join(base, inc))
if include:
try:
include(inc, remap=remap, sections=sections)
except IOError, inst:
if inst.errno != errno.ENOENT:
raise error.ParseError(_("cannot include %s (%s)")
% (inc, inst.strerror),
"%s:%s" % (src, line))
continue
if emptyre.match(l):
continue
m = sectionre.match(l)
if m:
section = m.group(1)
if remap:
section = remap.get(section, section)
if section not in self:
self._data[section] = sortdict()
continue
m = itemre.match(l)
if m:
item = m.group(1)
cont = True
if sections and section not in sections:
continue
self.set(section, item, m.group(2), "%s:%d" % (src, line))
continue
m = unsetre.match(l)
if m:
name = m.group(1)
if sections and section not in sections:
continue
if self.get(section, name) is not None:
del self._data[section][name]
continue
raise error.ParseError(l.rstrip(), ("%s:%s" % (src, line)))
def read(self, path, fp=None, sections=None, remap=None):
if not fp:
fp = util.posixfile(path)
self.parse(path, fp.read(), sections, remap, self.read)