fix: incorrect variable name display in must_get_env error msg

[mdqst]

noticed a bug in the must_get_env function where the error message was showing the value reference (${!VAR_VALUE}) instead of the actual variable name (${VAR_NAME}).

fixed it so that the error now correctly displays the name of the missing environment variable.

[jakubgs]

I don't really see any issue with that function as it is right now in develop:

~/work/status-mobile develop 51s
 > bash

[jakubgs@lilim:~/work/status-mobile]$ eval "$(sed -n '/function must_get_env/,+8p' scripts/build-android.sh)"

[jakubgs@lilim:~/work/status-mobile]$ must_get_env TEST
No required env variable: TEST
exit

[mdqst]

jakubgs hey, thanks for checking!

the problem is that in the error message you use ${!VAR_VALUE}, which expands to the variable’s value, not its name. so when the var is missing, it prints an empty string instead of the variable name.

If you run:

unset TEST_VAR
must_get_env TEST_VAR

the error shows

No required env variable:

without the name.

Changing it to just $1 will print the missing variable name correctly:

echo -e "${RED}No required env variable:${RST} ${BLD}$1${RST}" 1>&2

that way it shows:

No required env variable: TEST_VAR

[jakubgs]

How is that better?

[mdqst]

How is that better?

is better in terms of clarity, correctness, and consistency, especially in more complex scripts or when the script could be sourced.

[jakubgs]

The ! trick works because VAR_VALUE is not a variable but rather a reference to a var created via declare -n:

      -n	make NAME a reference to the variable named by its value

Which means that VAR_VALUE is a reference to $1. We can test this:

 > TEST=something
 > VAR_NAME=TEST
 > declare -n VAR_REF=$VAR_NAME
 > echo $VAR_REF
something
 > echo ${!VAR_REF}
TEST

Your version is clearer, but the result is the same. What I would like to understand is why for you it doesn't expand into the name of variable from the nameref.