sourcing a Bash script - Return on Error, instead of Exit?

Simply source the file with a failsafe:

source the-source-file || true

... then the overall command won't fail, even if source does.

This is the only thing that works for what I needed to accomplish (creating a virtual environment then activating it, then installing requirements from a bash script):

spawn a subshell / child shell from the script, as in:

stupid_file.sh

(
set -o errexit
#bunch of commands
#one line fails
)

run the stupid_file using:

source stupid_file.sh <file arguments here> || true

THE END.

** takes a bow **

(credit goes to Jeff and Terdon)