I've always heard it as a shorter alternative to "holy hell this tool is horrible but I'm unaware of an alternative, or cannot apply an alternative solution."

Are you sure? I have never interpreted it this way and it is the first way I hear this interpretation.

My understanding: To use something "for real" on an actual project, not just toy around with it. (What you use can be good or bad, expression doesn't say)

My interpretation has always been the same as mceachen's, but other comments in this sub-thread have thought me I am wrong and your understanding is correct. Today I learned.

For what it's worth[0]:

> If you do something in anger, you do it in a real or important situation as it is intended to be done, rather than just learning or hearing about it

[0] https://dictionary.cambridge.org/dictionary/english/in-anger

No, it's a military term. Firing a cannon in anger for instance means firing at the enemy, rather than in training.

Maybe adapted from "fire in anger":

https://www.bbc.co.uk/worldservice/learningenglish/radio/spe...

It’s military based isn’t it? First time you use a weapon “in anger” is to test its effectiveness in real world conflict

I don't think it necessarily means using it in production but rather using it on some non-trivial capacity that exposes you to it's various complexities and nuances such that you have more than just a surface level understanding. That probably coincides with using things in production a lot of the time, but that's not strictly necessary.

Yes it’s an old britishism - comes from “shots fired in anger” (as opposed to training)