tests/test-mq-symlinks

localrepo._tag: add a seek before writing the new tag

Some systems require a seek (or flush) between read and write
operations on the same file object.

This should fix issue838.

#!/bin/sh

echo "[extensions]" >> $HGRCPATH
echo "mq=" >> $HGRCPATH

cat >> readlink.py <<EOF
import errno, os, sys

for f in sys.argv[1:]:
    try:
        print f, '->', os.readlink(f)
    except OSError, err:
        if err.errno != errno.EINVAL: raise
        print f, 'not a symlink'
EOF

hg init
hg qinit
hg qnew base.patch
echo a > a
echo b > b
hg add a b
hg qrefresh
python readlink.py a

hg qnew symlink.patch
rm a
ln -s b a
hg qrefresh --git
python readlink.py a

hg qpop
hg qpush
python readlink.py a