pythonPackages.pyvcd: init at 0.1.4

[sbourdeauducq]

Motivation for this change

Add the pyvcd Python package required by some electronic design automation tools.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS) - Can't figure it out. Works fine with nix-shell --pure.
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• N/A Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• N/A Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• N/A Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size: < 1MB
• N/A Assured whether relevant documentation is up to date
• Fits CONTRIBUTING.md.

---

[dotlambda]

Adding yourself to maintainer-list.nix should be a separate commit. Also, prepend pythonPackages. to the existing commit's message.

[dotlambda]

@GrahamcOfBorg build python3.pkgs.pyvcd

[dotlambda]

Ran 0 tests in 0.000s

Please add an appropriate checkPhase or - if there are no tests - set doCheck = false and add a comment with the reason.

[sbourdeauducq]

Please add an appropriate checkPhase

Done and tests passing. Thanks for the quick review!

[dotlambda]

@GrahamcOfBorg build python2.pkgs.pyvcd python3.pkgs.pyvcd

[worldofpeace]

Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS) -
Can't figure it out. Works fine with nix-shell --pure.

By this we mean https://nixos.wiki/wiki/Nix_Package_Manager#Sandbox_builds.
And it's default enabled for NixOS since 18.09 I think.

[sbourdeauducq]

@dotlambda Thanks for the merge!

@worldofpeace I understood this, but when I try to use nix-build I get a confusing error message. Likely I'm doing something dumb...

$ nix-build -I nixpkgs=. -p "python3.withPackages(ps: with ps; [ pyvcd ])"
these derivations will be built:
  /nix/store/57x6z6360valwawys7dw387w2wac1sqw-python3-3.7.2-env.drv
  /nix/store/l3qv1nlaavy6llv0k4b2863fz3mdqbgz-shell.drv
building '/nix/store/57x6z6360valwawys7dw387w2wac1sqw-python3-3.7.2-env.drv'...
created 245 symlinks in user environment
building '/nix/store/l3qv1nlaavy6llv0k4b2863fz3mdqbgz-shell.drv'...
builder for '/nix/store/l3qv1nlaavy6llv0k4b2863fz3mdqbgz-shell.drv' failed to produce output path '/nix/store/vx5y03618gf3hwn94fa2lyry3nmd40fa-shell'
error: build of '/nix/store/l3qv1nlaavy6llv0k4b2863fz3mdqbgz-shell.drv' failed

[worldofpeace]

@worldofpeace I understood this, but when I try to use nix-build I get a confusing error message. Likely I'm doing something dumb...

$ nix-build -I nixpkgs=. -p "python3.withPackages(ps: with ps; [ pyvcd ])"
these derivations will be built:
  /nix/store/57x6z6360valwawys7dw387w2wac1sqw-python3-3.7.2-env.drv
  /nix/store/l3qv1nlaavy6llv0k4b2863fz3mdqbgz-shell.drv
building '/nix/store/57x6z6360valwawys7dw387w2wac1sqw-python3-3.7.2-env.drv'...
created 245 symlinks in user environment
building '/nix/store/l3qv1nlaavy6llv0k4b2863fz3mdqbgz-shell.drv'...
builder for '/nix/store/l3qv1nlaavy6llv0k4b2863fz3mdqbgz-shell.drv' failed to produce output path '/nix/store/vx5y03618gf3hwn94fa2lyry3nmd40fa-shell'
error: build of '/nix/store/l3qv1nlaavy6llv0k4b2863fz3mdqbgz-shell.drv' failed

I'd usually test by checking if the package builds for both python versions

nix-build -A python3.pkgs.pyvcd -A python.pkgs.pyvcd

Also noticed in your nix-build invocation that you specified the path to nixpkgs manually, and that isn't needed if you're current working directory is the checkout of nixpkgs.

And then using nix-shell to actually test if it works by using the result symlinks

nix-shell -p --pure ./result
nix-shell -p --pure ./result-2

You can also just do

nix-shell -I nixpkgs=. -p python.pkgs.pyvcd

[sbourdeauducq]

@worldofpeace Thank you. Yes, those nix-build commands work.

nix-shell -I nixpkgs=. -p python.pkgs.pyvcd is what I was using for testing, but this does not use sandboxing.