Decode map environment variable overwrites existing one even with env_not_set condition

[Bauke]

Hi, thanks for making and maintaining cargo-make, I really like it! I think I've come across a potential bug with conditionals and the decode map feature for environment variables. Here's an example Makefile.toml:

[tasks.conditional-source]
command = "echo"
args = ["${SOURCE_TEST}"]
env = {
  SOURCE_TEST = {
    condition = { env_not_set = ["SOURCE_TEST"] },
    source = "${SOURCE_IN}",
    default_value = "${SOURCE_IN}",
    mapping = { "one" = "1" }
  }
}

When I run this and don't have SOURCE_TEST set it works as expected and the one gets mapped to a 1. But when a SOURCE_TEST is defined it overwrites that one and again maps it.

$ SOURCE_IN="one" makers conditional-source
[cargo-make] INFO - Execute Command: "echo" "1"
1

$ SOURCE_IN="one" SOURCE_TEST="example" makers conditional-source
[cargo-make] INFO - Execute Command: "echo" "1"
1

# Instead I would expect to get:
[cargo-make] INFO - Execute Command: "echo" "example"
example

This is using version 0.37.5.

[sagiegurari]

@Bauke thanks for the feedback.
actually, i don't remember ever adding condition support for decode env vars definition and its not in the docs either.
i've only added it to simple definition and to script defintion.
see decode definition here:
https://github.com/sagiegurari/cargo-make/blob/601361645034c5e088eb337824a868d949ac6e2e/src/lib/types.rs#L453C1-L460C2

and all examples here:
https://github.com/sagiegurari/cargo-make/tree/master?tab=readme-ov-file#example

having said that, i think addition condition to decode env var definition is possible if thats what you are looking for.
would you like to PR that?

[Bauke]

Sure! I'll give it a shot.