>From https://github.com/HenrikBengtsson/Wishlist-for-R/issues/70 :
... and follow up note from 2018-03-15: Ouch... in R-devel, stopifnot() has
become yet 4-5 times slower;
...
which is due to a complete rewrite using tryCatch() and withCallingHandlers().
>From https://stat.ethz.ch/pipermail/r-devel/2017-May/074256.html , it seems
>that 'tryCatch' was used to avoid the following example from giving error
>message with 'eval' call and 'withCallingHandlers' was meant to handle similar
>case for warning.
tst <- function(y) { stopifnot(is.numeric(y)); y+ 1 }
try(tst())
However,
withCallingHandlers(,
warning = function(w) { w$call <- cl.i; w })
actally has no effect. In current code of function 'stopifnot', 'eval' is used
only in handling stopifnot(exprs=) . The warning message from
stopifnot(exprs={warning()})
has 'eval' call:
In eval(cl.i, envir = envir) :
This may work.
withCallingHandlers(,
warning = function(w) {
w$call <- cl.i; warning(w); invokeRestart("muffleWarning") })
Current documentation says:
Since R version 3.5.0, expressions are evaluated sequentially, and hence
evaluation stops as soon as there is a "non-TRUE", asnindicated by the above
conceptual equivalence statement. Further, when such an expression signals an
error or warning, its conditionCall() no longer contains the full stopifnot
call, but just the erroneous expression.
I assume that "no longer contains ..." is supposed to be the effect of the use
of 'withCallingHandlers' and 'tryCatch' in 'stopifnot'.
Actually, "contains the full stopifnot call" is not always the case in R before
version 3.5.0. Normally, the call is the "innermost context".
Example:
stopifnot((1:2) + (1:3) > 0)
Warning message:
In (1:2) + (1:3) :
longer object length is not a multiple of shorter object length
Example that gives error:
stopifnot(is.na(log("a")))
R 3.5.0:
R 3.3.2:
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