--allow-empty-values option will break Windows compatibility about dotenv-hs

[CristhianMotoche]

I do think we should care about windows support. There are some Haskell developers that use Windows and may found this library useful.

I had this concern a long time ago, you can check #7. I think the only solution for compatibility is using CPP.

[jsl]

Dotenv has implementations in many other languages. Can someone check what other implementations do for this case? Once we gather that information, we can choose behavior for dotenv-hs - preferably, something that is relatively flexible and safe.

[CristhianMotoche]

I've tried the following .env file

FOO=
BAR=1234

with js dotenv

require('dotenv').config();

if(process.env.FOO === undefined){
  console.log("Foo is not set");
} else {
  console.log("Foo is set");
}

console.log('Foo', process.env.FOO);
console.log('Bar:', process.env.BAR);

and ruby dotenv.

require 'dotenv'
Dotenv.load('.env')

if ENV['FOO'].nil?
  print("Foo is not set\n")
else
  print("Foo is set\n")
end

print('FOO: ' + ENV['FOO'] + "\n")
print('BAR: ' + ENV['BAR'] + "\n")

In both cases the output is:

Foo is set
FOO:
BAR: 1234

Looking into the code, it seems they only use their own basic libraries to manage environmental variables:

• js dotenv
• ruby dotenv

[CristhianMotoche]

Just in case, I did the same example with dotenv-hs:

import Configuration.Dotenv
import System.Environment

main :: IO ()
main = do
  loadFile False ".env"
  foo <- lookupEnv "FOO"
  bar <- lookupEnv "BAR"
  case foo of
    Nothing -> putStrLn "Foo is not set"
    Just _ -> putStrLn "Foo is set"
  putStrLn ("Foo: " ++ show foo)
  putStrLn ("Bar: " ++ show bar)

And I got the following output:

Foo is not set
Foo: Nothing
Bar: Just "1234"

[habibalamin]

Wasn't there a related issue on this repository about blank environment variables not being set by dotenv-hs?

I remember commenting on that with a workaround (because it was a wontfix to preserve Windows compatibility), but that only works on Haskell source files. It won't work if you need to load your .env file with something like dotenv -f .env -- command (for example, with supporting scripts).

I think being able to have blank environment variables is useful, and I kind of resent the fact that this Windows is acting as a lowest common denominator here (no offence to the team here, I can understand why you made the decision).

[CristhianMotoche]

@habibalamin Yeah, there is a PR (#7) where we discussed a little bit about it. I think it is good to have an issue open. We can have further discussions.

[CristhianMotoche]

Closing this issue because of #51 (comment)