After D11843, when running `arc diff` with only untracked changes within the working copy, the previous behaviour displaying the message 'To ignore these %s change(s)...' does not occur and user is not asked if they wish to add the untracked files to the commit.
The new behaviour appears to cause `arc diff` to launch the $EDITOR, with the new-commit template, without prompting to add files, therefore after completing the template and saving, arc attempts to run the linters and unit tests before returning: Usage Exception: No changes found. (Did you specify the wrong commit range?)
ArcanistWorkflow.php still appears to contain the warning messages for 'To ignore these %s change(s)...' but this check isn't processed as neither $unstaged or $uncommitted is true.
To reproduce
# `touch test.txt`
# `arc diff`
# Fill out template and save
Environment
- Ubuntu 14.04
- git 1.9.1
- libphuil eaa6ebecef8e577c594dbac8072333e8fd5ddaf4
- arcanist 4e984548404967e8a3b5091ec6d6cd57ddd3c8e3