It occurs to me that I could solve the problem by not trying to return data from the function at all. Instead, the function could just write the data to a global variable and then the caller could look at the contents of that global variable (since all variables in Bash are global by default unless I take steps to make them otherwise).

This would work around the issue, but it makes me cringe. I feel like there's got to be a way to do it in the more correct/structured fashion, if only I knew what it was. Still, if that's the only way to do it in Bash, so be it.