perl: run initLibStore() on openStore()

[Ma27]

Motivation

Fix calling openStore() from Perl code (needed e.g. in Hydra)

Context

Since #7478 it's mandatory that initLibStore() is called for store operations. However that's not the case when running openStore() in Perl using the perl-bindings. That breaks e.g. hydra-eval-jobset when built against Nix 2.13 which uses small portions of the store API.

Checklist for maintainers

Maintainers: tick if completed or explain if not relevant

• agreed on idea
• agreed on implementation strategy
• tests, as appropriate
  • functional tests - tests/**.sh
  • unit tests - src/*/tests
  • integration tests - tests/nixos/*
• documentation in the manual
• code and comments are self-explanatory
• commit message explains why the change was made
• new feature or bug fix: updated release notes

[edolstra]

Shouldn't it call initLibStore() instead? initNix() is pretty invasive, e.g. it messes with signal handlers.

If you do need to use initNix(), then the call to loadConfFile() should be removed since initNix() already does that.

[roberth]

Shouldn't it call initLibStore() instead?

I'm making some changes to make that suggestion work.

• in other words tech debt issue Move more of the initialization into nix::initLibStore #7502

[Ma27]

@roberth @edolstra so, how shall we proceed here? I guess for Hydra's use-case initLibStore() is sufficient, but I'm not so sure about other things using the Perl bindings.

[Ericson2314]

I would just do initLibStore. If it worked before without any such init, then it will work today with a no-op initLibStore.

[Ericson2314]

(Really I would consider all initialization for sake of ambient authority tech debt, it is indeed unclear when it is needed! As we improve the situation over time with explicit capabilities one passes around, it will become clearer what one is supposed to do. @roberth's PR is still good for at least narrowing the scope of which things need the ambient authority; it is like a triaging step.)

[Ericson2314]

Now just rename the PR title! :)

[Ericson2314]

This is future work, but I am thinking another lesson here is that bindings (Perl, but we wish to have more in the future) should have basic tests.

[Ma27]

Now just rename the PR title! :)

Also updated the PR's description.

Also, I guess this is a candidate for backporting to 2.13?

[Ericson2314]

Yes it should be, since it fixes a regression.

[Ma27]

Yes it should be, since it fixes a regression.

@Ericson2314 can you add the necessary label, would've done it, but I can't %)

[github-actions]

Successfully created backport PR for 2.13-maintenance:

• [Backport 2.13-maintenance] perl: run initLibStore() on openStore() #7746

[roberth]

Merged so that we can potentially deliver the fix sooner.

A follow-up with a test would be much appreciated.