How to use setupHook/shellHook in the new cli (nix shell)

Et7f3 commented 2 months ago

Problem

$ nix shell nixpkgs#python3Packages.diagrams nixpkgs#python3
$ python3 -c 'import diagrams'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ModuleNotFoundError: No module named 'diagrams'
$ ^D
exit
$ nix-shell -p python3Packages.diagrams python3
[nix-shell:/tmp]$ python3 -c 'import diagrams'
[nix-shell:/tmp]$

I can't find this behavior in v2 cli. In nix develop the hooks are called. I tried the mkShell technique (used by nix-shell): nix-shell -p abcd <=> {...}@args: with import <nixpkgs> args; (pkgs.runCommandCC or pkgs.runCommand) "shell" { buildInputs = [ (abcd) ]; } "" So I tried nix shell nixpkgs#runCommand --argstr name shell to set the first parameter but I got:

$ nix shell nixpkgs#runCommand --argstr name shell
error: '--arg' and '--argstr' are incompatible with flakes
Try 'nix --help' for more information.

Should I use -E ? then it would become relly fat expression and then writing a proper flake.nix is more concise.

Proposal

None I need help

Checklist

[x] checked latest Nix manual (source)
[x] checked open documentation issues and pull requests for possible duplicates I saw a closed PR with unanswered question https://github.com/NixOS/nix/issues/2854#issuecomment-904059622

Priorities

Add :+1: to issues you find important.

Qyriad commented 2 months ago

Shells created by nix shell are, confusingly, entirely different from those created by nix-shell and nix develop. The latter two create development shells, aka "the shell for building X package", the former creates "the shell for using X package"

Try using nix develop

See also: #4715

Et7f3 commented 2 months ago

Thanks I forgot to mention this thread (I have read before opening this issue). IIRC it also mentioned shellHooks that was not called so I opened this issue to track it. I understand the difference between the three:

nix develop nixpkgs#X and then genericBuild build package X in the env in the sandbox without sandbox limitations
nix-shell ./shell.nix with often mkShell put us in the building shell (but since mkShell is a fake builder it doesn build)
nix shell nixpkgs#python3 does add python3 binary in path but it only import binary without hook to expose library.

with nix-shell we could do nix-shell -p 'python3.withPackages(p:[p.diagrams])' and it create a python with a usable library. It is not a syntax usable with flake (that expect only attribute and not a function with args: we can't use --args/--argstr)

Here is the issue: The documentation explain "the shell for using X package" but should be "the shell for using X binary package" or allow to also use library.

Try using nix develop

nix shell nixpkgs#python3Packages.diagrams only a non-existent path:

$ nix shell nixpkgs#python3Packages.diagrams --command sh -c 'env | grep diagrams'
PATH=/nix/store/ilnk4wsnfppadn74apcfbbcpj4a1f3zi-python3.11-diagrams-0.23.4/bin:...
$ ls /nix/store/ilnk4wsnfppadn74apcfbbcpj4a1f3zi-python3.11-diagrams-0.23.4/bin
ls: cannot access '/nix/store/ilnk4wsnfppadn74apcfbbcpj4a1f3zi-python3.11-diagrams-0.23.4/bin': No such file or directory

only python3: I get callable python and both:

$ nix shell nixpkgs#python3 nixpkgs#python3Packages.diagrams --command sh -c 'env | grep diagrams; python3 -c "import diagrams"'
PATH=/nix/store/ilnk4wsnfppadn74apcfbbcpj4a1f3zi-python3.11-diagrams-0.23.4/bin:/nix/store/7wz6hm9i8wljz0hgwz1wqmn2zlbgavrq-python3-3.11.8/bin:...
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ModuleNotFoundError: No module named 'diagrams'

I have tried hard before opening issue (but since I did many test I didn't put them all because I forgot)

NixOS / nix