[R-pkg-devel] Procedure for dealing with reverse dependency that has gone bad on CRAN version of my package

[J C Nash]

In correcting a minor bug in the optimx package, I submitted a new version today.
The existing CRAN version (2024-12.2) has all CRAN checks OK, and to my knowledge
no notifications of bugs. The new version has hit a FAIL with package phenofit revdep.
Wanting to have output from a "working" system, I (re-)installed the CRAN version
of optimx and ran R CMD check on phenofit, and also get the FAIL on one of its tests.

The failure is a solve error (singularity) in the called minimizer nlminb, so could be
a result of some alteration in something like the matrix routines. I've also seen
changes in tests due to use of M1 and similar processors, relaxed IEEE arithmetic
being the cause. Such differences in outcome are not really a surprise, but can
be a nuisance.

My query is how to proceed to resolve this situation. Since my existing package --
which was supposedly OK back in December -- also throws the test failure in phenofit,
I've no path to reverse changes in my code. It's also possible there's no error
in phenofit, just a test case that now trips up when it did not prior to some
external change.

Still, some resolution is needed, and it would be good to avoid too much fuss.

John Nash