tests/test-custom-filters

hgfixes: add a fixer to convert plain strings to bytestrings

This patch implements a 2to3 fixer that converts all plain strings in a python
source file to byte strings syntax. Example:

foo = 'Normal string'

would become

foo = b'Normal string'

The motivation behind this fixer can be found in
http://selenic.com/pipermail/mercurial-devel/2010-June/022363.html or, in other
words: the current hg source assumes that _most_ strings are "meant" to be byte
sequences, so it makes sense to make the convertion implemented by this patch.

As mentioned above, not all mercurial modules want to use strings as bytes,
examples include i18n (which uses unicode), and demandimport (in py3k, module
names are normal strings, thus unicode, and there's no need for a convertion).
Therefore, these modules are blacklisted in the fixer. There are also a few
functions that can take only unicode arguments, thus the convertion shouldn't
be done for those.

#!/bin/sh

hg init

cat > .hg/hgrc <<EOF
[extensions]
prefixfilter = prefix.py
[encode]
*.txt = stripprefix: Copyright 2046, The Masters
[decode]
*.txt = insertprefix: Copyright 2046, The Masters
EOF

cat > prefix.py <<EOF
from mercurial import util
def stripprefix(s, cmd, filename, **kwargs):
    header = '%s\n' % cmd
    if s[:len(header)] != header:
        raise util.Abort('missing header "%s" in %s' % (cmd, filename))
    return s[len(header):]
def insertprefix(s, cmd):
    return '%s\n%s' % (cmd, s)
def reposetup(ui, repo):
    repo.adddatafilter('stripprefix:', stripprefix)
    repo.adddatafilter('insertprefix:', insertprefix)
EOF

cat > .hgignore <<EOF
.hgignore
prefix.py
prefix.pyc
EOF

cat > stuff.txt <<EOF
Copyright 2046, The Masters
Some stuff to ponder very carefully.
EOF
hg add stuff.txt
hg ci -m stuff

echo '% Repository data:'
hg cat stuff.txt

echo '% Fresh checkout:'
rm stuff.txt
hg up -C
cat stuff.txt
echo >> stuff.txt <<EOF
Very very carefully.
EOF
hg stat

cat > morestuff.txt <<EOF
Unauthorized material subject to destruction.
EOF

echo '% Problem encoding:'
hg add morestuff.txt
hg ci -m morestuff
hg stat