UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.181 Safari/537.36

Steps to reproduce the problem:
1. Start a git branch of chromium that doesn't track anything
2. Make some code changes
3. Run 'git cl format <origin/master|something else>'

What is the expected behavior?
According to the error message produced by 'git cl format':

$ git cl format origin/master
Unable to determine default branch to diff against.
Either pass complete "git diff"-style arguments, like
  git cl upload origin/master
or verify this branch is set up to track another 
(via the --track argument to "git checkout -b ...").

So when I include an explicit branch it should be able to format.

What went wrong?
1 - the command said 'git cl upload origin/master' when I was actually using 'git cl format' which could be confusing
2 - It didn't actually do any formatting, just showed the error message and exit.

Did this work before? N/A 

Chrome version: 65.0.3325.181  Channel: stable
OS Version: 
Flash Version: 

Everything worked correctly after I ran

'git branch -u origin/master'

Which implies that the branch specifier I was using was reasonable.