The rss-bridge service changes introduced in f2201789fe
resp. https://github.com/NixOS/nixpkgs/pull/223148 removes the need for
the package patch. This commit removes the patch to ease updating and
maintenance.
Relevant service functionality was also removed (e.g. the setting of
RSSBRIDGE_DATA).
The explicit definition of FileCache.path so users can easily see its
default value and change it, requires to use a freeformType to let users
freely add potentially upcoming config options. This type is restricted
to ini types (although we coerce them to environment variables).
This however makes the list of enabled_bridges impossible. That was
fixed by explicitly introducing this option with a type allowing lists.
The default value however should be unset, which is expressed as `null`,
which further spurred a change in the environment variable generation to
ignore null values (instead of coercing them to an empty string).
A breaking change note was added to highlight this change. A check that
warns users of the not-application of their existing config file is
not easily possible, as people could have only added or changed the
config.ini.php file on the file system without changing a nix variable.
In preparation for the deprecation of `stdenv.isX`.
These shorthands are not conducive to cross-compilation because they
hide the platforms.
Darwin might get cross-compilation for which the continued usage of `stdenv.isDarwin` will get in the way
One example of why this is bad and especially affects compiler packages
https://www.github.com/NixOS/nixpkgs/pull/343059
There are too many files to go through manually but a treewide should
get users thinking when they see a `hostPlatform.isX` in a place where it
doesn't make sense.
```
fd --type f "\.nix" | xargs sd --fixed-strings "stdenv.is" "stdenv.hostPlatform.is"
fd --type f "\.nix" | xargs sd --fixed-strings "stdenv'.is" "stdenv'.hostPlatform.is"
fd --type f "\.nix" | xargs sd --fixed-strings "clangStdenv.is" "clangStdenv.hostPlatform.is"
fd --type f "\.nix" | xargs sd --fixed-strings "gccStdenv.is" "gccStdenv.hostPlatform.is"
fd --type f "\.nix" | xargs sd --fixed-strings "stdenvNoCC.is" "stdenvNoCC.hostPlatform.is"
fd --type f "\.nix" | xargs sd --fixed-strings "inherit (stdenv) is" "inherit (stdenv.hostPlatform) is"
fd --type f "\.nix" | xargs sd --fixed-strings "buildStdenv.is" "buildStdenv.hostPlatform.is"
fd --type f "\.nix" | xargs sd --fixed-strings "effectiveStdenv.is" "effectiveStdenv.hostPlatform.is"
fd --type f "\.nix" | xargs sd --fixed-strings "originalStdenv.is" "originalStdenv.hostPlatform.is"
```
