Default values for environment variables

[jayvdb]

Is there a way to set an environment variable, only if it is not already set?

i.e. I would like to have a value which defaults to --all-features, but would like for the user be able to set it to -no-default-features

[sagiegurari]

@jayvdb ya you can do something like the below:

PREFER_EXISTING = { value = "new", condition = { env_not_set = ["PREFER_EXISTING"] } }

see more at:

https://github.com/sagiegurari/cargo-make#conditional
https://github.com/sagiegurari/cargo-make#global-configuration