[GNC] XDG_CONFIG_HOME

[Geert Janssens]

Op maandag 16 april 2018 20:10:16 CEST schreef Fross, Michael:
> Just so I'm clear:
> 
> XDG_DATA_HOME will point to the GNC config directory on linux.
> GNC_DATA_HOME will do likewise on Windows?  And the config directory is
> essentially the .gnucash from the v2.6 release?
> 
> I think this is right, just making sure I understand.
> 
> Thank you,
> 
> Michael

Hi Michael,

No it's more subtle than that.

The XDG_* variables come from a free desktop specification [1] that defines a 
number standard directories and paths that each system that claims to follow 
this standard should adhere to. Most desktop environments (kde, gnome, 
xfce,...) on linux do adhere to this so they can interoperate properly. Many 
programs rely on this, and gnucash is no exception as it's based on gtk (which 
underpins the gnome desktop environment as well).

There are two that gnucash uses as of gnucash 3.0 and related to user data:
XDG_DATA_HOME (defaults to ~/.local/share on linux)
XDG_CONFIG_HOME (defaults to ~/.config on linux)

On systems that follow the XDG specification, users can override either by 
setting environment variables with these names. In practice this is everywhere 
except on Windows and in the Quarz version of gnucash. Both of these instead 
use the platform specific default paths and will ignore the XDG_* settings 
[2].

As you may observe neither path is specific to gnucash. These directories are 
shared by all applications adherering to the above specification. So in order 
to keep these directories tidy, most applications make an application specific 
subdirectory in there. For gnucash on linux these are (predictably)
~/.local/share/gnucash
~/.config/gnucash

The former can be overridden by setting GNC_DATA_HOME, the latter can't be 
overridden (that's an oversight, not intentional).

Lastly, the 2.6 .gnucash dir has no one to one mapping to a directory under 
3.0. In fact it's content has been distributed over the two directories above. 
The rationale is this:
Any configuration file we expect the user to tweak manually should go in 
config/gnucash. GnuCash will never alter any file in there (except for the 
one-time initial migration. Any file we don't expect the user to tweak 
manually (as it's written and maintained by gnucash itself) should go into 
local/share/gnucash. We expect users to not touch these files directly and 
gnucash can overwrite these at any time.

Files that should go in .config are things like a customized css file, a 
config file with custom scheme code, ...
Files that still go in .local/share are saved reports (gnucash manages these), 
state files, style sheets,...

Currently the accelerator-maps are also still stored in there, but I believe 
this is a mistake as well that should be corrected at some point.

I hope this additional background info is helpful.

Regards,

Geert


[1] https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html
[2] this is not completely true, but I'm trying to to complicate it even more. 
The be precise: gnucash itself will ignore the two environment variables on 
Windows and OS X/Quarz, but some of its dependencies don't (like you can set 
XDG_CONFIG_HOME to tweak where gtk looks for its user config for example).