R devel - Jul 2023 - logic tweak needed for as.data.frame.<class> deprecation warning

Continuing the thread started on R-package-devel, here:
https://stat.ethz.ch/pipermail/r-package-devel/2023q3/009307.html

The logic of the now soft-deprecated as.data.frame.<class>,

 > body(as.data.frame.integer)[[2L]]
if ((sys.nframe() <= 1L || sys.call(-1L)[[1L]] != quote(as.data.frame))
&&
     nzchar(Sys.getenv("_R_CHECK_AS_DATA_FRAME_EXPLICIT_METHOD_"))) 
.Deprecated(msg = gettextf("Direct call of '%s()' is deprecated. 
Use '%s()' or
'%s()' instead",
     "as.data.frame.integer", "as.data.frame.vector",
"as.data.frame"))

may need adjustment to avoid false positives such as this one:

 > Sys.setenv("_R_CHECK_AS_DATA_FRAME_EXPLICIT_METHOD_" = TRUE)
 > f <- as.data.frame
 > f(0L)
   0L
1  0
Warning message:
Direct call of 'as.data.frame.integer()' is deprecated.  Use 
'as.data.frame.vector()' or 'as.data.frame()' instead

i.e., the condition sys.call(-1L)[[1L]] != quote(as.data.frame) is not precise
enough ... would !identical(sys.function(-1L), as.data.frame) work instead?

Mikael

Another issue raised in the earlier thread is that as.data.frame.POSIXlt
still calls as.data.frame.POSIXct.  Hence another path to a false positive
deprecation warning would be:

 > Sys.setenv("_R_CHECK_AS_DATA_FRAME_EXPLICIT_METHOD_" = TRUE)
 > as.data.frame(as.POSIXlt(.POSIXct(0, "UTC")))
   as.POSIXlt(.POSIXct(0, "UTC"))
1                     1970-01-01
Warning message:
Direct call of 'as.data.frame.POSIXct()' is deprecated.  Use 
'as.data.frame.vector()' or 'as.data.frame()' instead

as.data.frame.POSIXlt could simply change to using as.data.frame.vector.

I glanced at the other non-deprecated as.data.frame.<class> and did not
see other usage of the deprecated ones ... a more systematic check could
be worth doing.

Mikael

On 2023-07-06 11:32 am, Mikael Jagan wrote:
> Continuing the thread started on R-package-devel, here:
> https://stat.ethz.ch/pipermail/r-package-devel/2023q3/009307.html
> 
> The logic of the now soft-deprecated as.data.frame.<class>,
> 
>   > body(as.data.frame.integer)[[2L]]
> if ((sys.nframe() <= 1L || sys.call(-1L)[[1L]] != quote(as.data.frame))
&&
>      
nzchar(Sys.getenv("_R_CHECK_AS_DATA_FRAME_EXPLICIT_METHOD_")))
> .Deprecated(msg = gettextf("Direct call of '%s()' is
deprecated.  Use '%s()' or
> '%s()' instead",
>       "as.data.frame.integer", "as.data.frame.vector",
"as.data.frame"))
> 
> may need adjustment to avoid false positives such as this one:
> 
>   > Sys.setenv("_R_CHECK_AS_DATA_FRAME_EXPLICIT_METHOD_" =
TRUE)
>   > f <- as.data.frame
>   > f(0L)
>     0L
> 1  0
> Warning message:
> Direct call of 'as.data.frame.integer()' is deprecated.  Use
> 'as.data.frame.vector()' or 'as.data.frame()' instead
> 
> i.e., the condition sys.call(-1L)[[1L]] != quote(as.data.frame) is not
precise
> enough ... would !identical(sys.function(-1L), as.data.frame) work instead?
> 
> Mikael

>>>>> Mikael Jagan 
>>>>>     on Thu, 6 Jul 2023 11:32:00 -0400 writes:
    > Continuing the thread started on R-package-devel, here:
    > https://stat.ethz.ch/pipermail/r-package-devel/2023q3/009307.html

    > The logic of the now soft-deprecated as.data.frame.<class>,

    >> body(as.data.frame.integer)[[2L]]
    > if ((sys.nframe() <= 1L || sys.call(-1L)[[1L]] !=
quote(as.data.frame)) &&
    >
nzchar(Sys.getenv("_R_CHECK_AS_DATA_FRAME_EXPLICIT_METHOD_")))
    > .Deprecated(msg = gettextf("Direct call of '%s()' is
deprecated.  Use '%s()' or
    > '%s()' instead",
    > "as.data.frame.integer", "as.data.frame.vector",
"as.data.frame"))

    > may need adjustment to avoid false positives such as this one:

    >> Sys.setenv("_R_CHECK_AS_DATA_FRAME_EXPLICIT_METHOD_" =
TRUE)
    >> f <- as.data.frame
    >> f(0L)
    > 0L
    > 1  0
    > Warning message:
    > Direct call of 'as.data.frame.integer()' is deprecated.  Use 
    > 'as.data.frame.vector()' or 'as.data.frame()' instead

    > i.e., the condition sys.call(-1L)[[1L]] != quote(as.data.frame) is not
precise
    > enough ... would !identical(sys.function(-1L), as.data.frame) work
instead?


    > Mikael


Thank you, Mikael!

Indeed, as I see that it seems not even more costly than using sys.call(),
*and* because you gave me a case, where the previous, even
updated code, even lead to an error:

  > mapply(as.data.frame, x=1:10, row.names=letters[1:10])
  Error in (c1 <- sys.call(-1L)[[1L]]) != quote(as.data.frame) :
      comparison (!=) is possible only for atomic and list types

I have amended the code, using sys.function(-1L) in the first check
which does fix the above error and catches more false positives.

This is now in  R-devel svn rev >=  84653
and is planned to eventually be ported to the R 4.3.x series,
i.e., currently "R 4.3.1 patched".

Martin