sample_multinomial_op.o causing build from source to fail

[aaronmarkham]

I can't build mxnet on master from source anymore (from a fork or a regular repo)… getting this error:

make: *** No rule to make target 'include/mxnet/././../../src/common/random_generator.h', needed by 'build/src/operator/random/sample_multinomial_op.o'.  Stop.

I updated my submodules... I just pulled latest:

ubuntu@ip-172-31-66-78:~/incubator-mxnet$ git log
commit e213286db5f885701ee10d0a312c15564959edd9
Author: Sandeep Krishnamurthy <sandeep.krishna98@gmail.com>
Date:   Fri Sep 14 10:18:49 2018 -0700

I can checkout a fresh clone and build, but why should I have to do that? What needs to happen to fix my existing repos?

Commented here: #12374 as it seems related.

[lupesko]

@aaronmarkham can you clarify - when you clone a fresh repo, can you build normally?
If so - could this have been an issue with your repo?

[kalyc]

@mxnet-label-bot[Installation]
@aaronmarkham could you paste your environment config here?

[aaronmarkham]

I just needed to do a make clean apparently. I don't want to have to do this as part of my shell scripts because then I have to rebuild every time. It saves a lot of time to keep the build intact. What's the best practice on dealing with these kinds of failures that get introduced and you're trying to automate the builds?

[aaronmarkham]

@mxnet-label-bot[CI]
This issue really only comes up with the developing with the scripts used for CI. Since CI doesn't cache the intermediate artifacts (the build folders) this never pops up. But if you're developing with it and having to run full site builds, you need to run these scripts locally, and it is super nice having a build finish in seconds instead about 40 minutes. Injecting make clean in the process gets around this problem when someone "breaks the build", but ruins the time savings you get from cacheing the build folders.

So.... thoughts?