For .env, we use the following pattern:

export KEY="value" # comment

Actual behavior after we parse such file:

>>> os.getenv('KEY')
'"value" # comment'

Expected behavior:

>>> os.getenv('KEY')
'value'

The tricky part here is that # can be contained within the quoted value (e.g. KEY="#"), so we can't ignore everything after the #.

What is worse, bash requires # to be at the beginning of the token, so something like this is valid:

bash$ KEY=#value
bash$ echo $KEY
#value

Ruby dotenv works fine with trailing comments, but it uses a complicated regular expression to do that.