Bazaar tries to write 0-length strings to files

There are a few places where we might try to create an empty file.

Often this is done using Transport.put_bytes('') or Transport.put_bytes_non_atomic('').
In either case we end up doing something like:
  os.write(fd, '')

It seems that on Mac OS X, when you mount a Samba share, this fails. I'm not sure why it is the only place that doesn't like writing 0 bytes to a file.

This works around it at the Local transport layer. Such that we don't try to write a zero length string:

=== modified file 'bzrlib/transport/local.py'
--- bzrlib/transport/local.py 2007-10-04 22:00:07 +0000
+++ bzrlib/transport/local.py 2007-11-15 18:06:02 +0000
@@ -185,7 +185,8 @@
         except (IOError, OSError),e:
             self._translate_error(e, path)
         try:
- fp.write(bytes)
+ if bytes:
+ fp.write(bytes)
             fp.commit()
         finally:
             fp.close()
@@ -265,8 +266,12 @@

     def put_bytes_non_atomic(self, relpath, bytes, mode=None,
                              create_parent_dir=False, dir_mode=None):
- def writer(fd):
- os.write(fd, bytes)
+ if bytes:
+ def writer(fd):
+ os.write(fd, bytes)
+ else:
+ def writer(fd):
+ pass #Nothing to write
         self._put_non_atomic_helper(relpath, writer, mode=mode,
                                     create_parent_dir=create_parent_dir,
                                     dir_mode=dir_mode)