CI env variable displays warning if it's a string

[altdsoy]

Hello,

I'm not sure if the description is good enough, but I'm using a CI tool (Woodpecker CI) that injects the CI ENV variable with a string value.

It seems that when hex is checking its configuration it also checks this ENV.

In the following commit: 5eb05bd , its value is checked against a boolean:

def to_boolean(nil), do: {:ok, nil}
def to_boolean(false), do: {:ok, false}
def to_boolean(true), do: {:ok, true}
def to_boolean("0"), do: {:ok, false}
def to_boolean("1"), do: {:ok, true}
def to_boolean("false"), do: {:ok, false}
def to_boolean("true"), do: {:ok, true}
def to_boolean("FALSE"), do: {:ok, false}
def to_boolean("TRUE"), do: {:ok, true}
def to_boolean(_), do: :error

In my case because I don't have control on this ENV variable, Hex ends up considering it's an error and I'm getting an annoying warning on every mix command in my CI pipeline:

Invalid Hex config, falling back to default. Source: environment variable CI= "woodpecker".

I would like to open a PR but I wanted to discuss for an idiomatic way to solve this.

We can simply assume a truthy value for this ENV in particular (maybe using something like to_truthy_boolean) ?

[supersimple]

That does sound annoying.
It is also an interesting behavior by woodpecker to not allow their predefined env vars to be modified.
Admittedly, this could just as easily my classified as a design error in their product as a deficiency in the Hex API.
If we were to make a change, my suggestion would be to write a special function like this to deal with the CI value (and treat it as you said, truthy or non-truthy. But, keeping that logic hidden inside of a private function.)
If you put up a PR, I am compelled to approve it. @ericmj @wojtekmach any objections?

[wojtekmach]

Are you able to overwrite that value eg CI=true mix deps.get or set

environment:
  CI: true

Or something along those lines?

But if not, your patch is fine by me, I think it’d be nice on principle to continue being stricter but in this particular case I can’t see how it could be harmful.