Previously, the garbage collector found runtime roots on Darwin by
shelling out to `lsof -n -w -F n` then parsing the result.
However, this requires an lsof binary and can be extremely slow.
The official Apple lsof returns in a reasonable amount of time,
about 250ms in my tests, but the lsof packaged in nixpkgs is quite slow,
taking about 40 seconds to run the command.
Using libproc directly is about the same speed as Apple lsof,
and allows us to reënable several tests that were disabled on Darwin.
Change-Id: Ifa0adda7984e13c15535693baba835aae79a3577
I think it is bad for these reasons when `tests/` contains a mix of
functional and integration tests
- Concepts is harder to understand, the documentation makes a good
unit vs functional vs integration distinction, but when the
integration tests are just two subdirs within `tests/` this is not
clear.
- Source filtering in the `flake.nix` is more complex. We need to
filter out some of the dirs from `tests/`, rather than simply pick
the dirs we want and take all of them. This is a good sign the
structure of what we are trying to do is not matching the structure
of the files.
With this change we have a clean:
```shell-session
$ git show 'HEAD:tests'
tree HEAD:tests
functional/
installer/
nixos/
```
(cherry picked from commit 68c81c737571794f7246db53fb4774e94fcf4b7e)
Artemis Tosini
