How to display the error path of where the custom function is used? - css

Question

If I use a built-in Sass function that returns an error, it will display the path of where it is used.
Using a built-in Sass function:
Code from _test.scss.
.foo {
color: darken(blue, s);
}
Will result in:
error _test.scss (Line 2: $amount: "s" is not a number for `darken')
Now, if I use a custom function that returns an error, it will display the path of where it is defined instead of where it is used.
Using a custom function:
Code from _test.scss.
.foo {
color: example(string);
}
Code from _functions.scss.
#function example($string) {
#error 'error message';
}
Will result in:
error core/utils/_functions.scss (Line 2: error message)
Is there any solution for solving this "issue"?

Answer 1

Your examples are similar only visually, underlying logic is completely different:
For built-in function Sass throws error by itself because code is not valid from Sass point of view.
Into second example you're throwing error because code is not valid from your point of view. Code itself if valid from Sass point of view in this case.
In both cases Sass displays same information about error location - a point into your codebase where error occurs. But in a case of your own, intentional error throwing actual point where error occurs actually matches a place where you're generating this error - exactly at a place where you have your #error directive. So there is no mistake into Sass behavior because it knows nothing about reasons why did you decide to throw an error.
You can always analyze stack trace that is displayed (at least by node-sass) along with error message to decide where did you get to point of error from. You can also use #debug to display context that may be useful for error analysis.