Inconsistency with ruby dotenv: handling of alphabetical $ variables

[hpello]

What do you want to report?

Inconsistency with ruby dotenv

What version?

• godotenv v1.3.0
• dotenv-2.7.6

What do you observe?

When the x variable is not defined,
Numeric $x fields disappear, but alphabetical $x fields remain.
In the case of $_x, only the _ is swallowed.
=> It is not the same result with godotenv than with ruby's dotenv

What env file do you use?

• .env:

VARIABLE_0=$a$0$12$_x
VARIABLE_1="$a$0$12$_x"
VARIABLE_2='$a$0$12$_x'
VARIABLE_3=       $a$0$12$_x

What do you observe?

# result of: godotenv env | grep VARIABLE
VARIABLE_0=$ax
VARIABLE_1=$ax
VARIABLE_2=$a$0$12$_x
VARIABLE_3=$ax

What is the expected result?

With ruby's dotenv:

# result of: dotenv env | grep VARIABLE
VARIABLE_0=
VARIABLE_1=
VARIABLE_2=$a$0$12$_x
VARIABLE_3=