stack upgrade goes through entire build process, even when already up to date

[ojw]

Steps to reproduce:

Run stack upgrade.
After the upgrade, immediately run stack upgrade again.

Expected:
Stack will notice that it is up-to-date and not run the full build process the second time, probably reporting a message that it is up-to-date already.

Actual:
Stack runs through the build process again.

Here is the stack --version output:
Version 0.1.1.0, Git revision 91fe703

For the second run, the stack --version is:
Version 9.9.9

Here is the output of the command when I ran with stack upgrade --verbose:
http://pastebin.com/pZhc6t0n

[snoyberg]

Agreed, I commented on this limitation but forgot to open an issue about it. We should solve it. The 9.9.9 issue is a separate one, and a limitation of Hackage it seems...

[snoyberg]

I've pushed a commit for this. It doesn't do anything for the Git case, since that seems like a corner case to deal with, but when running stack upgrade, it will do nothing if the upstream version if <= the current version.