How to avoid creating an infinite loop when calling bash inside of bashrc with BASH_ENV set?

Question

Inside of ~/.bashrc, I run a bash script (a script with #!/usr/bin/env bash at the top). I have found that when BASH_ENV is set to my ~/.bashrc that this sets up an infinite loop when a bash command is run. What is the best way to avoid this?

Here is my understanding of what happens (see also the bash manual on startup files):

1. bash run non-interactively resolves BASH_ENV to ~/.bashrc.
2. bash begins sourcing ~/.bashrc.
3. bash gets to the line in ~/.bashrc that calls the bash script and starts a bash subprocess.
4. The bash subprocess resolves BASH_ENV to ~/.bashrc and so goes back to step 1 here, setting up an infinite loop.

I came across this issue because I wanted to run some cron jobs using my standard environment and found suggestions to set BASH_ENV within the crontab. I am posting this as a question here because I couldn't find the issue discussed in my searches online and it seems like something could bite others. I am posting my own solution below, but there may be better ones.

Answer 1

At the top of .bashrc put:

unset BASH_ENV

If .bashrc is already being sourced to set up the environment, there is no need for future calls to bash to set up the environment again.