plugins directory not found after default install

[bazwal]

exaile-0.3.0b1 running on linux2 (mandriva 2009.1)

after installing exaile using the default prefix of /usr/local, the plugins directory was not found on my system. this is because another application had already set XDG_DATA_DIRS, and the list of paths did not happen to include /usr/local/share.

i have fixed this by making sure XDG_DATA_DIRS is set properly in my bash_profile.

however, i think exaile should always enforce the inclusion of INSTALL_PREFIX/share/exaile in its list of data directories. at the moment, /usr/local/share is only guaranteed to be included if XDG_DATA_DIRS has not been set at all.

[reacocard (reacocard)]

We're just following the xdg spec exactly:

"If $XDG_DATA_DIRS is either not set or empty, a value equal to /usr/local/share/:/usr/share/ should be used." - http://standards.freedesktop.org/basedir-spec/basedir-spec-0.6.html

If another application has broken that default, then it's not our place to fix that application.

[bazwal (bazwal)]

yes, i looked at that spec. any application that sets XDG_DATA_DIRS should ensure that the default paths are included in the list. i have no argument with that.

what i was trying to get at was: installations of exaile may break if a prefix is used that is not in the list of xdg defaults.

for instance, if i installed exaile under the /opt directory, it would not find the plugins in /opt/share/exaile/plugins because /opt/share is not one of the default xdg data directories. (of course, some other application may have added it).

should users be able to choose where to install exaile? if so, at the very least, the installation instructions should include a warning about the possible consequences of doing that.

[reacocard (reacocard)]

> what i was trying to get at was: installations of exaile may break if a prefix is used that is not in the list of xdg defaults.

Yes, but the default prefix _is_ in the set of paths, and therefore it is my opinion that it is the user's job to ensure that they set XDG_DATA_DIRS appropriately if they choose a non-standard prefix.

> at the very least, the installation instructions should include a warning about the possible consequences of doing that.

true, this is worth mentioning.

[reacocard (reacocard)]

note added in r2349

[reacocard (reacocard)]

It occurred to me recently that we could fix this more-fully by setting these vars in the resulting PREFIX/bin/exaile script. we already do a similar action to this to set the path to the main exaile.py script. Logic for the additional code would be something like

if xdg_var is set, xdg_var=xdg_var:custom_location
else, xdg_var=xdg_defaults:custom_location

for both XDG_CONFIG_DIRS and XDG_DATA_DIRS

[Dan Fuhry (danfuhry)]

Here's my patch as discussed in IRC. It basically creates a launcher script which gracefully handles XDG_DATA_DIRS and the case of installation into a relative prefix.

If the system has readlink installed, relative prefix installation is supported; otherwise, the generate-launcher script will fail with an error message. The readlink utility is not required for absolute path installations (the vast majority of cases).

Before committing, chmod +x tools/generate-launcher

[reacocard (reacocard)]

patch committed trunk/2886, thanks!