Integer QCQP solution failure presumably caused by using certain wheels or Python versions.

[Viech]

Hello,

I've reported embotech/ecos#194 earlier this year and at the time the issue seemed to be caused by running ECOS 2.0.8 in combination with ecos-python 2.0.7, as updating the latter also to 2.0.8 had resolved it.

Now, the same issue has resurfaced on the latest Python 3.9 docker image, though I can reproduce it as well locally with Python 3.10 on Arch Linux. Note that just a month ago, the very same pipeline task ran without issues. As you can see from the logs, a month ago pip was building ecos-python from source, now it is using a wheel. (It is likely that also the third digit in the Python version of the Docker image has changed, which could explain the change from tarball to wheel.) In the case of Arch Linux, however, I can reproduce the issue building both ECOS and ecos-python from source (using this and that recipe respectively).

In summary, it seems that for recent Python versions the interface fails to handle integer QCQPs.