Improve flakes installables ergonomics, avoid nixpkgs# part?

[dramforever]

Is your feature request related to a problem? Please describe.

It's kind of annoying to keep typing nixpkgs# over and over in situations like:

$ nix shell nixpkgs#wireshark
$ nix run nixpkgs#peek

Especially considering that # is kinda hard to type.

Describe the solution you'd like

I feel like this should just work:

$ nix shell wireshark
$ nix run peek

To achieve this, I'm thinking about this scheme:

• If an INSTALLABLE does not contain either : or # looks like an attribute name like foo.bar.baz, resolve it to some default flake, like either flake:default#foo.bar.baz or flake:nixpkgs#foo.bar.baz
• Otherwise treat it as we do now

I'm not sure if this is the intention, but I think I am going to use stuff under nixpkgs# far more than the various other flakes. When we do need other flakes, just put a # after the flake name, i.e. foo# still means flake:foo, and things like github:owner/repo still means that flake.

Describe alternatives you've considered

• Give nixpkgs# a shorter name: Still a bit hard to type, even if it's just n#

Additional context

[dramforever]

This would be a breaking change, but I do believe that the impact will be minimal. Ideally this should just affect the use of the registry (i.e. flake:foo stuff), and only when accessing the default output, which I believe is a minority of the cases one would specify an INSTALLABLE. I could be very wrong about how flakes are actually/intended to be used though.

[edolstra]

The reasons why we didn't do this:

• It privileges nixpkgs over other flakes, while other flakes should be as easy to use as nixpkgs.
• It's ambiguous: it's not clear whether nix run wireshark means nixpkgs#wireshark or wireshark#defaultPackage.

I'm not sure if this is the intention, but I think I am going to use stuff under nixpkgs# far more than the various other flakes.

That's true today but might not be the case in a decentralized world where a lot of stuff isn't in nixpkgs.

[dramforever]

Okay, thanks for the clarification

[NickCao]

Allow omitting the flake ref part for nixpkgs as is may privileges nixpkgs. but instead, we can grant the choice back to the users, allow setting a default flake that would be used to resolve names in case of no other matches, or even better a search list (just like how podman handles multiple registries). For the ambiguity part, we may introduce special symbols into the definition of INSTALLABLES, @wireshark for example.

[dramforever]

I would really love to see how the community ends up using flakes. So I'm hoping that this UI is more open to discussion.

For my own use case, I have a package set which is nixpkgs with a overlay on top of it, with my packages and some tweaks and patches. The same flake also contains my NixOS configuration. So it would be wonderful personally if a default flake can be set.

That's true today but might not be the case in a decentralized world where a lot of stuff isn't in nixpkgs.

In a decentralized world, would it probably be expected that each user has a 'personal flake' that is used most often? I'm thinking about a flake with inputs referring to many other flakes as dependencies, and containing a package set and/or a nixosConfiguration for the machines a user has. It certainly seems like this is how many are making their flakes now.

As for the ambiguity problem, from a UI point of view, I'd prefer if there's no special character, but I think we can also reuse # such that #wireshark with an empty flake name would mean flake:default#wireshark.

[edolstra]

As for the ambiguity problem, from a UI point of view, I'd prefer if there's no special character, but I think we can also reuse # such that #wireshark with an empty flake name would mean flake:default#wireshark.

That could be an option, but # at the start of a token needs to be quoted, otherwise it's a comment in bash. So that makes it a bit less ergonomic.

[gytis-ivaskevicius]

How about this, fairly self-explanatory and would be nice and convenient:

nix run \#wireshark
... error of some sort

export DEFAULT_FLAKE_NAME_OR_SOMETHING=nixpkgs 
nix run \#wireshark
.... wireshark goes https://www.youtube.com/watch?v=XqZsoesa55w


export OR_MAYBE_DEFAULT_PREFIX_OR_SOMETHING=nixpkgs\#
nix run wireshark
....and wireshark goes https://www.youtube.com/watch?v=XqZsoesa55w

[nova-nowiz]

This thread is very interesting, I had a recent problem of setting a shell for testing where I had to write this:

nix shell nixpkgs#gcc nixpkgs#gnumake nixpkgs#openssh nixpkgs#p7zip

or

nix shell nixpkgs#cargo nixpkgs#rustc

for example.
writing the nixpkgs# once would be really nice:

nix shell nixpkgs#[gcc gnumake openssh p7zip]

I thought at some point that the --inputs-from option would solve my problem but this doesn't work for example:

nix run --inputs-from nixpkgs hello
error: cannot find flake 'flake:hello' in the flake registries

So my question is, is there a way to make it shorter?
Also, should I open another issue or is it fine to discuss this here @edolstra?

[nova-nowiz]

btw, you can shorten the name of nixpkgs with this command:

nix registry add n nixpkgs

[fogti]

@Narice bash afaik should also support

nix shell nixpkgs#{gcc,gnumake,openssh,p7zip}

[gytis-ivaskevicius]

🤔
I'd be down for nix shell --flake nixpkgs gcc gnumake openssh p7zip and similar for other commands. This way one could easily create an alias like this alias super-shell='nix shell --flake nixpkgs' to make life more convenient.

These days im like:

$ nix sh<C-f> # Ctrl+f - Autocompletes to something like '$ nix shell nixpkgs#gcc'
$ nix shell nixpkgs#gcc<C-BS> # Ctrl + backspace - deletes `gcc`
$ nix shell nixpkgs#<TypeWhateverINeed>

:D

[nova-nowiz]

Thanks @zseri!
That seems to work perfectly, awesome!