Globally extending pass_env

[Cadair]

Hello,

I am experimenting with nixos (opinions yet to be formed). I am using micromamba to set up environments, which is working well. However, to make micromamba happy on nixos I need to pass through the NIX_LD and NIX_LD_LIBRARY_PATH environment variables. If I do this in my projects tox.ini file like so:

[testenv:.pkg]
passenv = 
    NIX_LD
    NIX_LD_LIBRARY_PATH

[testenv]
passenv = 
    NIX_LD
    NIX_LD_LIBRARY_PATH

it works fine.

What I would like to know is if there is a way for me to configure my system to always pass these through for all my tox runs. I have tried to make a user config file:

$ cat ~/.config/tox/config.ini 
[testenv:.pkg]
pass_env = 
  NIX_LD
  NIX_LD_LIBRARY_PATH

[testenv]
passenv = 
  NIX_LD
  NIX_LD_LIBRARY_PATH

but that didn't work.

I also tried this:

$  export TOX_OVERRIDE="testenv.pass_env+=NIX_LD,NIX_LD_LIBRARY_PATH"
$  tox c -e .pkg
[testenv:.pkg]
type = Pep517VirtualEnvPackager
[...]
pass_env =
  CC
  CCSHARED
  CFLAGS
  CPPFLAGS
  CURL_CA_BUNDLE
  CXX
  FORCE_COLOR
  HOME
  LANG
  LANGUAGE
  LDFLAGS
  LD_LIBRARY_PATH
  NIX_LD
  NIX_LD_LIBRARY_PATH

Which looked hopeful but didn't actually pass the env through. Setting TOX_OVERRIDE="testenv:.pkg.pass_env+=NIX_LD,NIX_LD_LIBRARY_PATH" didn't seem to work either in reality or in the output of tox config.

Are there any other ways I can do this? or is any of this not working a bug? Thanks!

[gaborbernat]

The TOX_OVERRIDE approach is correct for this. If tox c shows the values in pass_env but they are not actually passed through at runtime, that sounds like a bug. Could you verify with a minimal reproducer — e.g. add printenv NIX_LD to your commands and confirm the variable is set in your shell but not reaching the tox env?

As an alternative, you could set a shell alias or wrapper script that always passes --override testenv.pass_env+=NIX_LD,NIX_LD_LIBRARY_PATH to tox invocations.

[gaborbernat]

Converted to issue #3860