commit: save commit message so it's not destroyed by rollback.
(
issue1635)
Rationale: if a pretxncommit hook rejects this commit, the transaction
is rolled back and the user's commit message is irrevocably lost.
So save a copy in .hg/last-message.txt, just in case. Also handy if
the user deliberately rolls back a commit in order to amend it.
#!/usr/bin/env python
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'
sys.exit(0)