explicitly set meta.mainProgram

[eclairevoyant]

Motivation

Setting meta.mainProgram properly allows using nix run correctly.

Context

NixOS/nixpkgs#246386 and nix run uses the same field.

Priorities

Add 👍 to pull requests you find important.

[edolstra]

This already works for me:

$ nix run nix -- --version
nix (Nix) 2.19.0pre20231013_d070d8b

[eclairevoyant]

• It's better to be explicit (as the linked PR mentions) rather than make assumptions
• This ensures the correct program is run even if pname/name is overridden for whatever reason
• There is no downside to adding this, only upside?

[NobbZ]

This already works for me:

$ nix run nix -- --version
nix (Nix) 2.19.0pre20231013_d070d8b

This change is more important for using lib.getExe from nixpkgs than it is for nix run.

[edolstra]

It's better to be explicit (as the linked PR mentions) rather than make assumptions

Not sure I agree with that. Convention over configuration and all that. Requiring thousands of packages to set mainProgram seems un-ergonomic.

[eclairevoyant]

Convention over configuration

I have never heard such a phrase, where does it come from?
Anyway, we are not talking about thousands of programs in this PR, only 1.

I do not see a reason to not-add it, and I see many reasons to add it, so I do not understand the strong and unnecessary pushback here.

[eclairevoyant]

If you want to know about the original nixpkgs PR (from 3 months ago) and why the warning was added, perhaps @roberth would be a better representative to explain the full context behind the PR than myself.

[Gerg-L]

If you want to know about the PR, perhaps @roberth would be a better representative to explain the full context behind the PR than myself.

The PR:
NixOS/nixpkgs#246386

[edolstra]

I have never heard such a phrase, where does it come from?

https://en.wikipedia.org/wiki/Convention_over_configuration

Anyway, I'll merge this since it is indeed just a one-liner.