rpy2 cffi failure

[yannikschaelte]

There seems to be a misbehavior of cffi 1.13.0, see https://bitbucket.org/rpy2/rpy2/issues/591/runtimeerror-found-a-situation-in-which-we
and conda-forge/rpy2-feedstock#35.
Until that is resolved, we require cffi==1.12.2 in .travis_pip_reqs (please also do that when using the R simulators in practice), but should undo that again as soon as the situation is resolved.

[lgautier]

Note that the issue seems restricted to using rpy2 with ccffic'c ABI mode. Using it through the API mode is still working with cffic1.13.0 (See box "Notes" at https://rpy2.github.io/doc/v3.2.x/html/overview.html#install-from-source).

[yannikschaelte]

Thanks for pointing this out @lgautier ! So that would also work. (I did not check in sufficient detail, just took, time-constrained, the first fix that worked.)

[lgautier]

rpy2 will try to use the API mode (more stable and recommended, from the cffi documentation, and with at one one addititonal feature available on the rpy2 side), but will quietly fallback to the ABI mode if it fails.

In time, some of the performance lost with rpy2's move from C-extension to cffi will be recovered, but I anticipate that most will only be available with the API mode.

[lgautier]

cffi 1.13.1 was just released and it includes a fix to the issue.

[yannikschaelte]

thanks for the update! we'll give it a try asap.