b4 emits color codes to pipes

I like to pipe emails from my MUA (notmuch-emacs) to 'b4 shazam'. It works great, as b4 parses the mails and picks up the message-id from there.

However, b4 seems to err on the side of emitting color codes to pipes, and I get something like this as output:

---
[32m✓[0m [PATCH v5->v6 1/6] drm/i915/hpd: Track HPD pins instead of ports for HPD pulse events
+ Reviewed-by: Jani Nikula <[email protected]> ([32m✓[0m DKIM/intel.com)
[32m✓[0m [PATCH v5->v6 2/6] drm/i915/hpd: Let an HPD pin be in the disabled state when handling missed IRQs
+ Reviewed-by: Jani Nikula <[email protected]> ([32m✓[0m DKIM/intel.com)
[32m✓[0m [PATCH v6 3/6] drm/i915/hpd: Add support for blocking the IRQ handling on an HPD pin
[32m✓[0m [PATCH v5->v6 4/6] drm/i915/dp: Fix link training interrupted by a short HPD pulse
+ Reviewed-by: Jani Nikula <[email protected]> ([32m✓[0m DKIM/intel.com)
[32m✓[0m [PATCH v6 5/6] drm/i915/dp: Queue a link check after link training is complete
[32m✓[0m [PATCH v5->v6 6/6] drm/i915/crt: Use intel_hpd_block/unblock() instead of intel_hpd_disable/enable()
---
[32m✓[0m Signed: DKIM/intel.com
---

I haven't had the time to dig into b4 source on this, but it would be great if it could automatically detect whether sending colors is the right thing to do or not. Basically only emit color codes to interactive terminals, unless forced also for pipes. I presume this would mean adding a new parameter --color={auto,always,never} similar to git, defaulting to auto.

Thanks,
Jani.

Jani Nikula, Intel