Help pages for stop/warning reference the option "warning.length", e.g.
from ?stop:
Errors will be truncated to getOption("warning.length") characters, default
> 1000.
Essentially the same is in ?warning.
Neither of these mention the hard-coded limits on the acceptable values of
this option in options.c
<https://github.com/wch/r-source/blob/a7356bf91b511287aacd3a992abfbcb75b60d93c/src/main/options.c#L546-L552>
:
if (streql(CHAR(namei), "warning.length")) {
int k = asInteger(argi);
if (k < 100 || k > 8170)
error(_("invalid value for '%s'"), CHAR(namei));
R_WarnLength = k;
SET_VECTOR_ELT(value, i, SetOption(tag, argi));
}
Further, it appears there's a physical limit on the length of the error
message itself which is only slightly larger than 8170:
set.seed(1023)
NN = 10000L
str = paste(sample(letters, NN, TRUE), collapse = '')
# should of course be 10000
tryCatch(stop(str), error = function(e) nchar(e$message))
# [1] 8190
My questions are:
- Can we add some information to the help pages indicating valid values
of options('warning.length')?
- Is there any way to increase the limit on error message length? I
understand having such a limit is safer than potentially crashing a system
that wants to print a massive error string.
This came up in relation to this SO Q&A:
https://stackoverflow.com/a/50387968/3576984
The user is submitting a database query; the error message will first
reproduce the entirety of the query and then give some diagnostic
information. Queries can get quite long, so it stands to reason that this
8190-length limit might be binding.
Thanks,
Michael Chirico
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