Compare feature doesn't show diff when the compare branch is behind the base branch

[ERElli]

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Possible bug when using the Compare feature.

The compare feature seems to behave like git diff so it feels weird that there is not diff shown when the compare branch is behind the base branch.

I would expect that compare would show the code subtractions instead of telling me there is nothing to compare. From this, I would assume that the two branches are equal which is clearly not the case.

Steps to reproduce:

1. Create a branch that is some number of commits behind another branch. For example:

git checkout master
git fetch
git reset --hard origin/master
git checkout -b removed_commits
git reset --hard HEAD~3

2. Push this new branch
3. Go to https://github.com/{path-to-your-repo}/compare
4. Set the base branch to master
5. Set the compare branch to removed_commits
6. Compare will tell you there is nothing to compare