It was never meant to be used for anything other than testing
and setting it globally can cause weird loops in GTK-based portals,
where the portal will end up waiting for itself until it times out.
https://github.com/NixOS/nixpkgs/issues/135898
Or it can mess up fonts:
https://github.com/NixOS/nixpkgs/issues/155291#issuecomment-1166199585
Having the option in NixOS makes it look like it is okay or even
desirable to enable, when in fact it is a hack that can subtly break apps.
Some apps allow opting into using portal-based APIs, e.g. for Firefox,
you can set `widget.use-xdg-desktop-portal.file-picker` to `1` in about:config.
Otherwise, you can set the `GTK_USE_PORTAL` environment variable to 1
for individual apps.
People who really want it and aware of the downsides can just set
`environment.sessionVariables.GTK_USE_PORTAL = "1";` NixOS option
directly to set the environment variable globally.
A centralized list for these renames is not good because:
- It breaks disabledModules for modules that have a rename defined
- Adding/removing renames for a module means having to find them in the
central file
- Merge conflicts due to multiple people editing the central file
If lib.optional is given a false value it will return an empty list.
Thusly the set-environment script can have
```
export GTK_USE_PORTAL=
```
This can rub certain bugs the wrong way #65679
so lets make sure this isn't set in the environment
at all.
Prior to this change GTK_USE_PORTAL was unconditionally
set to "1". For this to not break things you have to have some
sort of portal implementation in extraPortals.
Setting GTK_USE_PORTAL in this manner is actually only useful
when using portals for applications outside flatpak. For example
people using non-flatpak Firefox who want native filechoosers.
It's also WIP for electron applications to support this.
Left to do: re-enable as needed in the usual situations.
This added ~286MiB to the base system closure, which is enough to bring
the sd images over the limit allowed on Hydra.
Back in 2013, update-mime-database started using fdatasync() to write out
its changes after processing each file in /share/mime, with the reasoning
that a corrupted database from an interruption midway would be
problematic for applications[1]. Unfortunately, this caused a
significant regression in the time required to run update-mime-database:
commonly from under a second to half a minute or more.
This delay affects the time required to build system-path on NixOS, when
xdg.mime.enable is true (the default). For example, on one of my systems
system-path builds in ~48 seconds, 45 of which are update-mime-database.
This makes rapidly building new system configurations not fun.
This commit disables the calls to fdatasync(). update-mime-database
checks an environment variable, PKGSYSTEM_ENABLE_FSYNC, to determine
whether it should sync, and we can set this to false. system-path
already only has whatever filesystem commit guarantees that the Nix
builder provides. Furthermore, there is no risk of a failed MIME
database update messing up existing packages, because this is Nix.
(This issue was also reported at and discussed by Debian, Red Hat, and
Gentoo at least.)
[1] https://bugs.freedesktop.org/show_bug.cgi?id=70366
For update-mime-database to work, you must have to have some mime
packages installed. In some DEs like XFCE this is not guaranteed to
happen. In that case just skip the update-mime-database call.
Fixes#46162
