* devenv: Factor out a function to get the Nix version.
* devenv: On newer versions of Nix, use `NIX_USER_CONF_FILES`.
This stacks, rather than overwrites.
* devenv: Append Nix caches, instead of overwriting them.
The "extra-" prefix tells Nix to append.
We also switch to non-deprecated configuration keys.
CHANGELOG_BEGIN
CHANGELOG_END
* devenv: Just require Nix v2.4 or newer.
* devenv: `NIX_USER_CONF_FILES` may not be set already.
* Enable experimental nix command
Nix 2.4 got released which confusingly marked the nix command as
experimental despite it being actively worked on and being more stable
than before.
changelog_begin
changelog_end
* switch to CLI flag
changelog_begin
changelog_end
* Revert "switch to CLI flag"
This reverts commit 58d6a25d83.
Our CI nodes install nix in multi-user mode. This means that changing
cache information is only available to certain trusted users for
security reasons. The CI user is not part of those so the cache info
from dev-env/etc/nix.conf is silently ignored.
We could consider not running in multi-user mode although from a
security pov this seems like a pretty sensible decision and our
signing keys change very rarely so for now, I would keep it.
changelog_begin
changelog_end
We're rotating the nix key used by CI to sign our artifacts. This is step
1: add the new public key.
Step 2 will be to update the CI configuration to use the new key, and
step 3 will be the removal of the old key from this conf file.
CHANGELOG_BEGIN
CHANGELOG_END
* Update CI nix version
For `--option http2 false` to take effect requires Nix 2.3.2.
CHANGELOG_BEGIN
CHANGELOG_END
* Set option `http2 = false` dev-env nix config
This is less likely to overlook an instance than manually adding
`--option http2 false` to each Nix invocation.
Setting `--option htt2p false` also had no effect on the multi-user Nix
installation on the Linux CI machines due to
```
WARNING: option '--disk_cache' was expanded to from both option '--config linux' (source /nix/store/2xnfb2l39d2b4nxw5vwmqz5hjwhw0caw-daml-bazelrc) and option '--config linux' (source /nix/store/2xnfb2l39d2b4nxw5vwmqz5hjwhw0caw-daml-bazelrc)
```
Co-authored-by: Andreas Herrmann <andreash87@gmx.ch>
