Modify global Variable in a Bash Function called with a Pipe

Question

I have the following pattern in a bash script:

#!/bin/bash

a="Default"

the_function() {
    echo "Something"
    a="Set By Function"
}

Just a function that alters the value of a global variable.

If I call it, it works as intented, the following call (also in the same script):

echo $a
the_function
echo $a

Prints the expected:

Default
Something
Set By Function

But if I call the function and pipe its output, the variable is not altered (outside of the function):

This call:

echo $a
the_function | tee my-log-file.log
echo $a

The output:

Default
Something
Default

What is the difference in environment between a function call and a function call that pipes the output?
And how can I pipe the output and still have the variable altered?

Answer 1

Try

the_function >( tee my-log-file.log )

to avoid the pipe.