config: add sanity assert that files are opened as binary

This helps with some debugging in Python 3, and shouldn't hurt
anything in Python 2. The unusual construction using getattr is done
so that StringIO/BytesIO instances can be used as well as real files.

mercurial/config.py

@@ -1,174 +1,177
 # config.py - configuration parsing for Mercurial
 #
 #  Copyright 2009 Matt Mackall <[e-mail]> 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 __future__ import absolute_import
 
 import errno
 import os
 
 from .i18n import _
 from . import (
     error,
     util,
 )
 
 class config(object):
     def __init__(self, data=None, includepaths=[]):
         self._data = {}
         self._source = {}
         self._unset = []
         self._includepaths = includepaths
         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 hasitem(self, section, item):
         return item in self._data.get(section, {})
     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, n in src._unset:
             if s in self and n in self._data[s]:
                 del self._data[s][n]
                 del self._source[(s, n)]
         for s in src:
             if s not in self:
                 self._data[s] = util.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 backup(self, section, item):
         """return a tuple allowing restore to reinstall a previous value
 
         The main reason we need it is because it handles the "no data" case.
         """
         try:
             value = self._data[section][item]
             source = self.source(section, item)
             return (section, item, value, source)
         except KeyError:
             return (section, item)
 
     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] = util.sortdict()
         self._data[section][item] = value
         if source:
             self._source[(section, item)] = source
 
     def restore(self, data):
         """restore data returned by self.backup"""
         if len(data) == 4:
             # restore old data
             section, item, value, source = data
             self._data[section][item] = value
             self._source[(section, item)] = source
         else:
             # no data before, remove everything
             section, item = data
             if section in self._data:
                 self._data[section].pop(item, None)
             self._source.pop((section, item), None)
 
     def parse(self, src, data, sections=None, remap=None, include=None):
         sectionre = util.re.compile(br'\[([^\[]+)\]')
         itemre = util.re.compile(br'([^=\s][^=]*?)\s*=\s*(.*\S|)')
         contre = util.re.compile(br'\s+(\S|\S.*\S)\s*$')
         emptyre = util.re.compile(br'(;|#|\s*$)')
         commentre = util.re.compile(br'(;|#)')
         unsetre = util.re.compile(br'%unset\s+(\S+)')
         includere = util.re.compile(br'%include\s+(\S|\S.*\S)\s*$')
         section = ""
         item = None
         line = 0
         cont = False
 
         for l in data.splitlines(True):
             line += 1
             if line == 1 and l.startswith('\xef\xbb\xbf'):
                 # Someone set us up the BOM
                 l = l[3:]
             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 and include:
                 expanded = util.expandpath(m.group(1))
                 includepaths = [os.path.dirname(src)] + self._includepaths
 
                 for base in includepaths:
                     inc = os.path.normpath(os.path.join(base, expanded))
 
                     try:
                         include(inc, remap=remap, sections=sections)
                         break
                     except IOError as 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] = util.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]
                 self._unset.append((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, 'rb')
+        assert getattr(fp, 'mode', r'rb') == r'rb', (
+            'config files must be opened in binary mode, got fp=%r mode=%r' % (
+                fp, fp.mode))
         self.parse(path, fp.read(),
                    sections=sections, remap=remap, include=self.read)