load_all is Tripped Up By methods' setOldClass

[DarioS]

In my Bioconductor package, I have setOldClass("Surv") to make the class from survival package S4-friendly.

$ git clone https://github.com/SydneyBioX/ClassifyR.git # Download the package to disk.
$ cd ClassifyR
$ R
> devtools::load_all() # Works fine first time, warning the second time, error the third time.
Error in `load_all()`:
! Failed to load R/classes.R
Caused by error in `setOldClass()`:
! inconsistent old-style class information for “Surv”; the class is defined but does not extend
  “oldClass” and is not valid as the data part

In contrast, in RStudio Server, the error happens at the first time of execution, not the third.