fatal: CRLF would be replaced by LF in somefile.txt

I got an exciting new-to-me error from git today!

❯ git add .
fatal: CRLF would be replaced by LF in some-text-file-from-elsewhere.txt

A bit of googling found about ten thousand results all telling you to run the moral equivalent of dos2unix on it and move on. This is no good to me in this case - it's a text file I got from elsewhere and I don't want it altered at any point, not by me now, and not by git later if anyone happens to check it out on Windows. I spent a bit of time fiddling around with .gitattributes to try disable the core.autocrlf and/or auto.safecrlf settings per file before I eventually found this excellent StackOverflow post that mentions you just want to unset the text attribute on the file, which works out to be:

❯ echo "# this file came from the output of a command, so please don't mangle the line endings ever
some-text-file-from-elsewhere.txt -text" > .gitattributes
❯ git add .
❯

voila.