Give an example for --enable-nix flag

[blackheaven]

Just a clarification in the documentation

[fendor]

Does --enable-nix do anything for v2-* commands?

IIRC, --enable-nix only works for v1-* commands. Maybe we should rather document that or even remove the option altogether.

[blackheaven]

Does --enable-nix do anything for v2-* commands?

It does not seems to be involved in v2-* commands.

IIRC, --enable-nix only works for v1-* commands. Maybe we should rather document that or even remove the option altogether.

I think it's beyond the scope of this PR, but there's also --disable-nix, I'm not sure how it'll work if we keep v1-* commands.

[fgaz]

if we keep v1-* commands

The plan is to remove them "soon".
+1 on removing --enable/disable-nix altogether, even before removing v1- if it's easy
edit: main ticket: #4646

[fendor]

Even bigger context ticket to completely overhaul the flags displayed in cabal: #7437

[Kleidukos]

Until we explicitly decide to allocate resource and time to go forward with the flag deprecation, I'll vote in favour to integrate this PR.

[Mikolaj]

@blackheaven: are you a user of --enable-nix? Do we have users of that (I know we have users of v1-)?

[blackheaven]

@blackheaven: are you a user of --enable-nix? Do we have users of that (I know we have users of v1-)?

I was just struggling with Nix

[Mikolaj]

@blackheaven: are you a user of --enable-nix? Do we have users of that (I know we have users of v1-)?

I was just struggling with Nix

Then I'm +1 on improving the documentation for as long as we keep the option.

I seem to remember Nix is also used via the Setup interface, which is sort of v1-, but without involving cabal-install. Perhaps that's something you'd rather use? It's not going to be ripped out. OTOH, it doesn't need the --enable-nix flag. Please do let us know if you find out a better workflow than Nix+v1, so that we have one more data point re timeline of deprecation.

[Mikolaj]

I'm afraid this won't work with new enough cabals, because now build is an alias for v2-build. You probably want to say v1-build. Actually, if the flag does nothing with v2- commands, it would be great to also change all the examples below by prepending command names with v1-? Otherwise, we are just adding content to misleading documentation.

[Mikolaj]

LGTM. Thank you.

[blackheaven]

I seem to remember Nix is also used via the Setup interface, which is sort of v1-, but without involving cabal-install. Perhaps that's something you'd rather use? It's not going to be ripped out. OTOH, it doesn't need the --enable-nix flag. Please do let us know if you find out a better workflow than Nix+v1, so that we have one more data point re timeline of deprecation.

To give a broader context, at work we use nix + bazel for the build and ghcid.

I have started a toy project, and, trying to keep the same workflow, I have a hard time figuring out that packages should be injected from nix instead of having cabal "finding the packages".

Saying it out-loud seems reasonable, but the thing is, I had a hard time to find coherent examples.

[ulysses4ever]

If you only need ghcid, I think you could get away with simply nix-shell --run ghcid and avoid the legacy v1- commands altogether.

[blackheaven]

If you only need ghcid, I think you could get away with simply nix-shell --run ghcid and avoid the legacy v1- commands altogether.

Sure, but at the time I was trying to get something compiling.

[ulysses4ever]

Sure, but at the time I was trying to get something compiling.

I see. All I want to say is that I think that whatever it is that you're trying to do, it does not have to go via v1- commands and --enable-nix. And that you'd be better off with v2- commands. I'm happy to (try to) answer more specific questions if you have them.

Thank you for contributing and good luck anyway!

[fgaz]

Is mergify stuck?

[ulysses4ever]

Is mergify stuck?

@fgaz no, it's #8285.

[fgaz]

ooh so the waiting period is enforced by mergify now. neat!

[Mikolaj]

One more context ticket, after the fact: #6444