[pacman-dev] difficult symlink "puzzle"

[ngaba at petra.hos.u-szeged.hu]

Hi!
IMHO this problem is more general and serious, and this should be 
solved. Either you specify some strict Arch packaging standards to 
avoid this bug or you improve pacman. I prefer the 2nd, and that is not 
easy; I make some suggestions here to discuss:
First I define the goal: the content of foo's .FILELIST exists on 
filesystem iff foo is installed.
OK, I assume that the goal above holds for all installed package; we 
just need to keep this during package install/removal.
Install:
-If we install /dir/file: That exists until package foo is removed (in 
normal case). If dir is a symlink, we MUST record the "real" 
destination of file to localdb/foo/files too, because the dir symlink 
can be removed/modified during an other package removal (or update!!: 
you can easily imagine a modified perl example where current is a 
symlink to the latest version...) or by the user.
-If we install /dir/dir_symlink: First, we treat dir2 as a regular 
file, and do the steps above. Then we check if /dir1/dir2 exists. If 
no, we simply create it pointing to the requested dir. If yes and that 
is not a real dir, we can stop with file conflict. If yes and 
dir_symlink is a real dir, we can move its content to the 
dir_symlink-pointed dir, then delete/create_link dir_symlink; we must 
also record the file movements to the localdb as above (this is slow, 
queryfileowner needed, but this a rare case).
Remove:
-If we remove /dir/file: no extra work needed, just we need to use 
"real" path.
-If we remove /dir/dir_sl: If dir_sl_pointed is empty or doesn't exist, 
then simply remove dir_sl. If dir_sl_pointed is not empty then we must 
create a real dir named dir_sl, and moved some files (we scan localdb 
for files need to be installed as /dir/dir_sl/file) from dir_sl_pointed 
to there (and record the movements to localdb again.).
Bye, ngaba
PS: We can implement these without db conversion (and keep compatibility).


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