Astropy rebuilds whole project every time

[mdboom]

If you do python setup.py build and then python setup.py build immediately following, every thing gets rebuilt all over again.

git bisect tells me the first commit with this issue is ae38cc9

@embray, any thoughts?

[eteq]

I'm seeing the same thing, and likewise for python setup.py test, python setup.py build_sphinx, etc. Really makes it hard to work on the docs or anything that's test-driven... I see it with both clang and gcc, if that matters.

[astrofrog]

I found the issue and am fixing it here: astropy/astropy-helpers#11

Will close once astropy core is updated to the latest helpers version

[astrofrog]

@mdboom @eteq - this should be fixed by #2535, but feel free to re-open the issue if not.

[mdboom]

Thanks. This is working for me.

[embray]

FWIW I've almost always had this problem. I've found it easy to ignore thanks to ccache.