Due to a known limitation with RPM, it is not possible to replace a directory with any kind of file or symlink, nor is it possible to replace a symlink to a directory with a directory, without RPM producing file conflict errors while trying to install the package. For more information on the issues involved, refer to bug 447156 and bug 646523.
While its obviously not possible to foresee all the cases where the need might arise, when the need is foreseeable, such as with bundled libraries, it'd be better to use a symlink from the start, as the symlink target can be changed more easily. For instance, if you have a bundled libfoo library inside the packages directory structure, place it in a eg. libfoo.bundled directory and make libfoo a symlink to that. When the bundling is eventually removed, you just need to drop the directory and change the symlink to point to the corresponding system library directory, without resorting to the scriptlets described below.
To work around this problem, you must include a %pretrans scriptlet that manually performs the conversion prior to RPM attempting to install the package.
%pretrans scriptlets must use -p
-p
os.execute()
to actually perform the replacement.
Please use whichever of the two following snippets is necessary in packages that need this transition, replacing /path/to/dir
with the path to the directory that is being converted.
RPM cannot simply remove a directory when it is replaced by a file or symlink, since users may have added or modified files to the directory. To protect against accidental data loss, you must use the following scriptlet which renames the directory with a .rpmmoved
suffix so that users can find the backed up directory if they need to after the package is upgraded. (It also will append an integer to the suffix in the rare event that directory also exists.)
%pretrans -p <lua>
-- Define the path to directory being replaced below.
-- DO NOT add a trailing slash at the end.
path = "/path/to/dir"
st = posix.stat(path)
if st and st.type == "directory" then
status = os.rename(path, path .. ".rpmmoved")
if not status then
suffix = 0
while not status do
suffix = suffix + 1
status = os.rename(path .. ".rpmmoved", path .. ".rpmmoved." .. suffix)
end
os.rename(path, path .. ".rpmmoved")
end
end
Additionally, you should define the /path/to/dir.rpmmoved
directory as a %ghost
entry in the %files
list in the package's spec file, so that the directory is not entirely orphaned and can be deleted if the package is ever uninstalled and the directory is empty.
Replacing a symlink to a directory with a regular directory is much simpler, since there's no potential for accidentally removing files added externally. This scriptlet check the remove the symlink (there is no need to create the directory here, rpm will do so later when it is used):
%pretrans -p <lua>
-- Define the path to the symlink being replaced below.
path = "/path/to/dir"
st = posix.stat(path)
if st and st.type == "link" then
os.remove(path)
end