Repair pager for Python2.6

The pager used with `stg show`, `stg patches`, and `stg diff` comes from
the pydoc module in the Python standard library.

For Python 2.6, the pager attempts to encode the unicode text as ascii and
thus any non-ascii text causes the pager to crash.

To repair, we adopt the strategy used in Python 2.7: encode the text to be
paged using the locale's preferred encoding and 'xmlcharrefreplace' error
handling.

Repairs #19.

Signed-off-by: Peter Grayson <jpgrayson@gmail.com>

stgit/commands/diff.py

@@ -1,13 +1,13 @@
 # -*- coding: utf-8 -*-
 from __future__ import (absolute_import, division, print_function,
                         unicode_literals)
-from pydoc import pager
 
 from stgit import argparse, git
 from stgit.argparse import opt
 from stgit.commands.common import (DirectoryHasRepository,
                                    color_diff_flags,
                                    git_id)
+from stgit.compat import pager
 from stgit.lib import git as gitlib
 from stgit.out import out
 

stgit/commands/patches.py

@@ -1,11 +1,11 @@
 # -*- coding: utf-8 -*-
 from __future__ import (absolute_import, division, print_function,
                         unicode_literals)
-from pydoc import pager
 
 from stgit import argparse, git
 from stgit.argparse import opt
 from stgit.commands.common import CmdException, DirectoryHasRepository
+from stgit.compat import pager
 from stgit.out import out
 
 __copyright__ = """

stgit/commands/show.py

@@ -1,14 +1,13 @@
 # -*- coding: utf-8 -*-
 from __future__ import (absolute_import, division, print_function,
                         unicode_literals)
-from pydoc import pager
-
 from stgit import argparse, git
 from stgit.argparse import opt
 from stgit.commands.common import (DirectoryHasRepository,
                                    color_diff_flags,
                                    git_id,
                                    parse_patches)
+from stgit.compat import pager
 from stgit.lib import git as gitlib
 
 __copyright__ = """

stgit/compat.py

@@ -3,6 +3,7 @@
                         unicode_literals)
 import email
 import os
+import pydoc
 import sys
 
 # With unicode_literals enabled, the type of a string literal will be `unicode`
@@ -135,3 +136,13 @@ def decode_utf8_with_latin1(input, errors='strict'):
         else:
             break
     return s
+
+
+if sys.version_info[0:2] <= (2, 6):
+    def pager(text):
+        import locale
+        encoding = locale.getpreferredencoding()
+        b = text.encode(encoding, 'xmlcharrefreplace')
+        return pydoc.pager(b)
+else:
+    pager = pydoc.pager

stgit/main.py

@@ -8,7 +8,7 @@
 import traceback
 
 from stgit import argparse, run, utils
-from stgit.compat import environ_get, fsdecode_utf8
+from stgit.compat import environ_get, fsdecode_utf8, pager
 from stgit.config import config
 from stgit.out import out
 import stgit.commands
@@ -136,7 +136,6 @@ def _main():
             parser = argparse.make_option_parser(command)
             if is_cmd_alias(command):
                 parser.remove_option('-h')
-            from pydoc import pager
             pager(parser.format_help())
         else:
             print_help()