git-fast-import doc problem and git-fast-export does not quote filenames correctly

[Michael Haggerty <mhagger@alum.mit.edu>]

According to the git-fast-import manpage:

> A `<path>` string must use UNIX-style directory separators (forward
> slash `/`), may contain any byte other than `LF`, and must not
> start with double quote (`"`).
> 
> If an `LF` or double quote must be encoded into `<path>` shell-style
> quoting should be used, e.g. `"path/with\n and \" in it"`.
> 
> The value of `<path>` must be in canonical form. That is it must not:
> 
> * contain an empty directory component (e.g. `foo//bar` is invalid),
> * end with a directory separator (e.g. `foo/` is invalid),
> * start with a directory separator (e.g. `/foo` is invalid),
> * contain the special component `.` or `..` (e.g. `foo/./bar` and
>   `foo/../bar` are invalid).
> 
> It is recommended that `<path>` always be encoded using UTF-8.

The first problem is that the doc seems to allow NUL bytes (which I
suspect are not really allowed) or the backslash '\' character (which,
if allowed, would logically have to be escaped, too).

The second problem is that "git fast-export" does not do even the
specified quoting:

$ git init
Initialized empty Git repository in /home/mhagger/tmp/gitfoo/.git/
$ touch '"path with
 and " in it"'
$ git add -u
$ git commit -am 'Madness'
[master (root-commit) 2472bdb] Madness
 0 files changed, 0 insertions(+), 0 deletions(-)
 create mode 100644 "\"path with\n and \" in it\""
$ git fast-export --all
blob
mark :1
data 0

reset refs/heads/master
commit refs/heads/master
mark :2
author Michael Haggerty <mhagger@michael.localdomain> 1283580642 +0200
committer Michael Haggerty <mhagger@michael.localdomain> 1283580642 +0200
data 8
Madness
M 100644 :1 "path with
 and " in it"

reset refs/heads/master
from :2

Michael