S7 method<- errors when called from non-installed pseudo-package

[t-kalinowski]

Here, the current working directory is a real package, pkgb. pkgb imorts pkga, and pkga calls method<-. Attempting to only partially load pkgb with roxygen2::load_source() signals this cryptic error.

> roxygen2::load_source(".")
Error in `loadNamespace()`:
! there is no package called ‘roxygen_devtest’
Run `rlang::last_trace()` to see where the error occurred.
> rlang::last_trace()
<error/rlang_error>
Error in `loadNamespace()`:
! there is no package called ‘roxygen_devtest’
---
Backtrace:
     ▆
  1. └─roxygen2::load_source(".")
  2.   └─base::lapply(package_files(path), sys_source, envir = env)
  3.     └─roxygen2 (local) FUN(X[[i]], ...)
  4.       └─base::eval(expr, envir = envir)
  5.         └─base::eval(expr, envir = envir)
  6.           └─S7::`method<-`(`*tmp*`, Variable, value = `<fn>`)
  7.             └─S7:::register_method(generic, signature, value, env = parent.frame())
  8.               └─S7:::external_methods_add(package, generic, signature, method)
  9.                 └─S7:::S7_methods_table(package)
 10.                   └─base::asNamespace(package)
 11.                     └─base::getNamespace(ns)
 12.                       ├─.Internal(getRegisteredNamespace(name)) %||% ...
 13.                       └─base::loadNamespace(name)
 14.                         └─base::withRestarts(stop(cond), retry_loadNamespace = function() NULL)
 15.                           └─base (local) withOneRestart(expr, restarts[[1L]])
 16.                             └─base (local) doWithOneRestart(return(expr), restart)

(roxygen_devtest is a pseudo package env created by roxygen2. We don't need to support roxygen specially here, but S7 should be robust to the asNamespace() call failing.)

[mmaechler]

well... I apologize for being somewhat controversial ...
but, as S7 should become a very basic R package and possibly even base or "base - like" ..
Why would it have to support a concept (viz. "pseudo package") that is I think entirely outside of base R?
Shouldn't the other package writers (in this case maintainer("roxygen2") adapt to basic S7 functionality rather than the other way around?