updmap.cfg, update-updmap and removed packages: Yet an other approach
Hi,
I had an idea for a totally different approach to the problem that
removed packages leave their map files on the system, but must
deactivate them. I'm not yet convinced that it is better than what
Florent has designed, especially because I haven't completely written it
down yet - but if it works, it would have certain advantages.
The main advantage is the reason why I'm sending this to this bug
(Original title: updmap-sys --enable-map should act on 00updmap.cfg).
The problem in this bug is that according to upstream's documentation
(and, of course, many resources on the web and in newsgroups and mailing
lists) one can permanently enable map files with "updmap[-sys] --enable
[Mixed]Map=...". This edits updmap.cfg, and of course will be
overwritten by update-updmap every time this command is run.
In the original bug report, I suggested that we patch updmap-sys to act
on 00updmap.cfg instead. However, since map entries can be in different
files in updmap.d, it is unclear on which file in this directory it
should actually act. This is even more severe for --disable, which
would need to parse all cfg files in updmap.d. If people start
combining updmap-sys --enable with editing of files in that directory,
the outcome is even more complicated (there may be two entries for one
map file...).
Furthermore such a patch to updmap-sys will lead to further code
divergence from upstream, making maintenance of the code more
difficult.
Therefore I propose the following scheme:
updmap.cfg is a configuration file in /etc/texmf/. update-updmap does
not just concatenate the files in updmap.d; instead it parses them, and
acts on each Map line (I'm going to say Map in the following, the same
holds for MixedMap of course) in turn. Basically, it runs "updmap-sys
--enable Map=..." for every line, and writes the same information into a
file in /var/, let's call it fontmap.var. The purpose of this file is
to be able to compare the actual setting with the setting provided by
the previous conffile that has just been replaced.
Preservation of local configuration during upgrade or while a package is
removed works as follows:
1. For every map line in updmap.d/*.cfg, a line is written to
fontmap.var. The line indicates whether the corresponding package is
installed or removed, and what the setting is in the conffile in
updmap.d. Let's say there's a I for installed and a R for removed, a
whitespace and the line itself. In the case of R, an additional + or
- follows the R to indicate whether there was a discrepancy between
the conffile setting and the local setting.
2. If a package was purged and is now installed, update-updmap does not
find any information about the map lines in fontmap.var. Therefore
2.1) for "Map enabled.map" in updmapd.d/*.cfg it writes to fontmap.var
I Map enabled.map
and calls
updmap-sys --enable Map enabled.map
2.2) for "#! Map disabled.map" in updmapd.d/*.cfg it writes to fontmap.var
I #! Map disabled.map
and calls
updmap-sys --enable Map disabled.map # to add a line at all
updmap-sys --disable disabled.map # to disable it
3. If the user changes the settings in updmap.cfg, the next time
update-updmap acts on this Map line it notices that the setting is
different in fontmap.var and updmap.cfg and respects the setting in
updmap.cfg, i.e. it doesn't call updmap-sys --[en|dis]able.
4. If the conffile in updmap.d changes (either because the package
changes, or because the local admin changes it and runs
update-updmap) it goes like this:
4.1) conffile changes from enabled to disabled
4.1.1) setting in updmap.cfg and fontmap.var is enabled (i.e. no
local change): Change setting to disabled in both files
4.1.2) enabled in fontmap.var, disabled in updmap.cfg (i.e. local
change): Change setting to disabled in fontmap.var. Now all
three files have the same information, no problem in the
future
4.2) conffile changes from disabled to enabled
4.2.1) settings in updmap.cfg and fontmap.var are diabled (i.e. no
local change): Change setting to disabled in both files
4.2.2) disabled in fontmap.var, enabled in updmap.cfg (i.e. local
change): Change setting to enabled in fontmap.var. Now all
three files have the same information, no problem in the
future
5. If the file is removed, but not purged, updmap-sys is called with
--disable in all cases, but the current state in updmap.cfg is
written into fontmap.var, with R prepended instead of I. If this
means a change to the setting (i.e. there was a local change), R- is
written R+ otherwise.
6. If after removal the package is reinstalled
6.1) with a conffile setting now enabled:
6.1.1) setting in fontmap.var is
R+ #!...
(i.e. previously map file was disabled in conffile and
updmap.cfg, no local changes):
Enable in upmap.cfg and fontmap.var
6.1.2) setting in fontmap.var is
R- #!...
(i.e. previously map file was enabled in conffile but
disabled in updmap.cfg, local change):
Disable in upmap.cfg, enable in fontmap.var
6.1.3) setting in fontmap.var is
R+ Map...
(i.e. previously map file was enabled in conffile and
in updmap.cfg, no local change):
Enable in upmap.cfg and fontmap.var
6.1.3) setting in fontmap.var is
R- Map...
(i.e. previously map file was disabled in conffile but
enabled in updmap.cfg, local change):
Enable in upmap.cfg and fontmap.var
6.2) with a conffile setting now disabled:
6.2.1) setting in fontmap.var is
R+ #!...
(i.e. previously map file was disabled in conffile and
updmap.cfg, no local changes):
Disable in upmap.cfg and fontmap.var
6.2.2) setting in fontmap.var is
R- #!...
(i.e. previously map file was enabled in conffile but
disabled in updmap.cfg, local change):
Disable in upmap.cfg and fontmap.var
6.2.3) setting in fontmap.var is
R+ Map...
(i.e. previously map file was enabled in conffile and
in updmap.cfg, no local change):
Disable in upmap.cfg and fontmap.var
6.2.3) setting in fontmap.var is
R- Map...
(i.e. previously map file was disabled in conffile but
enabled in updmap.cfg, local change):
Enable in upmap.cfg, disable in fontmap.var
Uff. I think this would work.
It would get even nicer if we enhance updmap's --enable with a
--comment=".." option that writes the comment line before the Map line
- surely Thomas Esser would accept such a patch.
And it makes it trivial to swap map files between packages, they simply
don't care about settings in files in updmap.d, because the actual local
setting is always in updmap.cfg (or fontmap.var after a removal)
Good night...
Frank
--
Frank Küster
Inst. f. Biochemie der Univ. Zürich
Debian Developer
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