Repository navigation
bug: deparse(conditionCall(cnd)) fails for errors raised in S7 methods #783
Description
Errors raised inside an S7 method record a call that contains the dispatched S7 object.
On R 4.3.3 that call can't be deparsed, so any tool using conditionCall() crashes.
library(S7)
Foo <- new_class("Foo")
g <- new_generic("g", "x")
method(g, Foo) <- function(x) stop("boom")
cnd <- tryCatch(g(Foo()), error = identity)
deparse(conditionCall(cnd))
#> Error in deparse(conditionCall(cnd)) :
#> 'S4SXP': should not happen - please reportrlang::as_label(conditionCall(cnd)) fails the same way.
The call's head is the method(g, Foo) symbol. Its dispatch argument is a forced promise holding the S7 object it looks like
R-devel has a commit makes deparse() handle these objects, but released R versions still fail.
Could S7 record a call that succesfully deparses, without expecting updating to R-devel?
Session info
─ Session info ─────────────────────────────────────────────────────────────── setting value version R version 4.3.3 (2024-02-29) os macOS 27.0 system aarch64, darwin20 ui X11 language (EN) collate en_CA.UTF-8 ctype en_CA.UTF-8 tz America/Toronto date 2026-10-14─ Packages ───────────────────────────────────────────────────────────────────
package * version date (UTC) lib source
S7 * 0.2.2.9000 2026-10-14 [1] Github (426c13e)
Activity
Only route S7-object arguments through `...` in method calls (RConsor…
t-kalinowski commentedon Oct 14, 2026
Thanks for opening this issue. You don’t need to switch to R-devel: this deparsing error was fixed in R 4.4.0, released in April 2024, over two years ago. Updating to R 4.4 or a later stable release should resolve it. If upgrading isn’t an option, we also have a draft S7 fix for R 4.2 and 4.3.
jjjermiah commentedon Oct 20, 2026
oh this is great thank you!!!