slot "subclasses" from an object of a basic class ("NULL") with no slots" on Mac occasionally just happens

[aleighbrown]

This error keeps happening to me occasioanlly and now seems to persist. I cannot load 'tidyverse' due to an error with dbplyr

I've seen this error before #779 and had previously resolved by devtools::install_github("RobinHankin/Brobdingnag)"

However, for whatever reason it's not working this time

I have reinstalled from GitHub the Brobdingnag, dplyr, and tidyverse packages. Restarted my R, restarted my computer

> library(tidyr)

Attaching package: ‘tidyr’

The following objects are masked from ‘package:Matrix’:

    expand, pack, unpack

> library(magrittr)

Attaching package: ‘magrittr’

The following object is masked from ‘package:tidyr’:

    extract

> library(dbplyr)
Error in completeSubclasses(classDef2, class1, obj, where) : 
  trying to get slot "subclasses" from an object of a basic class ("NULL") with no slots
Error: package or namespace load failed for ‘dbplyr’:
 .onLoad failed in loadNamespace() for 'dbplyr', details:
  call: setClass(cl, contains = c(prevClass, "VIRTUAL"), where = where)
  error: error in contained classes ("character") for class “ident”; class definition removed from ‘dbplyr’

Version info

platform       x86_64-apple-darwin17.0     
arch           x86_64                      
os             darwin17.0                  
system         x86_64, darwin17.0          
status                                     
major          4                           
minor          2.1                         
year           2022                        
month          06                          
day            23                          
svn rev        82513                       
language       R                           
version.string R version 4.2.1 (2022-06-23)
nickname       Funny-Looking Kid     

[mgirlich]

Sorry, this is not a dbplyr issue and there is nothing we can do about it. It might be due to another package you have installed. You could have a look at this issue from Brobdingnag to find other packages that might cause this.
Or you could try to figure out which package is responsible for this, maybe by adapting this reprex from Hadley

requireNamespace("Brobdingnag")
#> Loading required namespace: Brobdingnag
requireNamespace("Matrix")
#> Loading required namespace: Matrix
methods::setOldClass(c("ident", "character"))
#> Error in completeSubclasses(classDef2, class1, obj, where) : 
#>   trying to get slot "subclasses" from an object of a basic class ("NULL") with no slots
#> Error in setClass(cl, contains = c(prevClass, "VIRTUAL"), where = where): error in contained classes ("character") for class "ident"; class definition removed from '.GlobalEnv'

and replacing Brobdingnag by other packages you have installed. Though, I can't promise you can figure it out like this.

@hadley In the other issue you mentioned a fix to R

I pinged Michael Lawrence about this and he also pushed a fix to R-devel: wch/r-source@3d97199

Do you know when/whether this is going to happen? I didn't find anything in the R changelog.

[mgirlich]

Closing this because it is not a dbplyr issue. Sorry we couldn't help you.

[lanjlgle]

I also encountered this error, but only when I open a rstudio project which had been created before, nor a newly created project or a new R session.

Then, I guess some objects related to dbplyr may be loaded from '.RData'. If I add "library(dbplyr)" into file 'Rprofile.site', the error never occur any more. Hope helps.