Hello again,
I have one more question to ask related to mime-support and mailcap files.
Packages can install mailcap entries in /usr/lib/mime/packages/, which are
collected by update-mime from the mime-support via Dpkg triggers, and used
to produce the file /etc/mailcap, together with the information collected
from the Desktop files in /usr/share/applications.
The format of mailcap files allows for continuation lines, when the last
character of a line is a backslash that escapes the newline character.
http://tools.ietf.org/html/rfc1524 (last paragraph of page 2).
update-mime supports this passively, since is to simply copies the contents of
the files in /usr/lib/mime/packages/ as they are. That is, they are not
parsed.
However, this leads to the following bug. The file /etc/mailcap.order can be
used to reorder the contents of the mailcap file according to the local user's
priorities. But this is done with line-by-line matching, and therefore, an
entry spanning two lines will be broken in two parts here and there in
/etc/mailcap.
Given that this bug has not been reported since the ~16 years that the
mailcap.order system is in place in Debian, I conclude that is at least very
rare. Indeed, Debian packages do not seem to use continuation lines in
the mailcap entries that they install in /usr/lib/mime/packages/:
To inspect them, I listed packages of interest with the following command:
apt-file search usr/lib/mime/packages | cut -f 1 -d ':' >
packagesWithMailcapFiles
I then used this list of packages to extract their mailcap files on
lintian.debian.org.
for package in $(cat packagesWithMailcapFiles)
do
for deb in /srv/mirrors/debian/pool/main/*/*/${package}_*_amd*deb
do
dpkg-deb --fsys-tarfile $deb | tar xf - ./usr/lib/mime/packages/$package
done
done
I am therefore tempted to acknowledge this current practice by officially not
supporting continuation lines in the files installed in
/usr/lib/mime/packages/, instead of implementing more complex parsing.
The way I would do it would be to test for the presence of a media type
at the beginning of each line, and emit a warning otherwise. This would
answer to http://bugs.debian.org/384161.
Please let me know if you see reasons for not doing so (and in that case,
patches are more than welcome).
Cheers,
--
Charles Plessy
Tsurumi, Kanagawa, Japan
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