Git blame showing no history

git blame file.txt blames the version of file.txt in your working copy. If file.txt has Windows-newlines (CRLF) in the repo and you have core.autocrlf = true, then every line of file.txt will be considered different and will be reported by git blame as not yet committed.

The reason why git blame <my_branch> (or even better git blame HEAD, which works no matter what branch you're on) works, is that it doesn't blame the working copy version so there's no potential for lines not yet being committed.

Found the solution - very weird.

If I run this:

git blame file.txt

The history is broken, as posted above.

If I do this instead:

git blame my_branch file.txt

It works!

This is very weird, because AFAICS the usage doesn't require a branch name:

$ git blame
usage: git blame [options] [rev-opts] [rev] [--] file