[Rd] Control statements with condition with greater than one should give error (not just warning) [PATCH]

[Henrik Bengtsson]

Here's a patch that enables the error if
_R_CHECK_CONDITION_={1,true,TRUE,yes,YES}.

$ svn diff
Index: src/main/eval.c
===================================================================
--- src/main/eval.c (revision 72303)
+++ src/main/eval.c (working copy)
@@ -1851,9 +1851,19 @@
     Rboolean cond = NA_LOGICAL;

     if (length(s) > 1) {
+ int val = 0; /* warn by default */
+ char *check = getenv("_R_CHECK_CONDITION_");
+ if (check != NULL) {
+    val = (strcmp("1", check) == 0 ||
+           strcasecmp("true", check) == 0 ||
+   strcasecmp("yes", check) == 0);
+        }
  PROTECT(s); /* needed as per PR#15990.  call gets protected by
warningcall() */
- warningcall(call,
-    _("the condition has length > 1 and only the first element will be used"));
+ if (val)
+    errorcall(call, _("the condition has length > 1"));
+        else
+    warningcall(call,
+ _("the condition has length > 1 and only the first element will be used"));
  UNPROTECT(1);
     }
     if (length(s) > 0) {

An alternative is to make _R_CHECK_CONDITION_=false the default behavior.


With this env variable, I think it'll be easier for a developer to
temporarily work around broken dependencies until fixed.  It will also
help identify broken dependencies.  For instance, as soon as one is
identified it can be wrapped up in an:

  with_faulty_conditions(x <- pkg::foo(...))

and additionally faulty if/while statements can be detected.  Your
package will still "work" until downstream packages are fixed.  Here,

with_faulty_conditions <- function(expr, envir = parent.frame()) {
  oenv <- Sys.getenv("_R_CHECK_CONDITION_")
  on.exit(Sys.setenv("_R_CHECK_CONDITION_" = oenv))
  Sys.setenv("_R_CHECK_CONDITION_" = FALSE)
  eval(substitute(expr), envir = envir)
}

/Henrik

On Sat, Mar 4, 2017 at 12:20 PM, Michael Lawrence
<lawrence.michael at gene.com> wrote:
> Is there really a need for these complications? Packages emitting this
> warning are broken by definition and should be fixed. Perhaps we could "flip
> the switch" in a test environment and see how much havoc is wreaked and
> whether authors are sufficiently responsive?
>
> Michael
>
> On Sat, Mar 4, 2017 at 12:04 PM, Martin Maechler
> <maechler at stat.math.ethz.ch> wrote:
>>
>> >>>>> Henrik Bengtsson <henrik.bengtsson at gmail.com>
>> >>>>>     on Fri, 3 Mar 2017 10:10:53 -0800 writes:
>>
>>     > On Fri, Mar 3, 2017 at 9:55 AM, Hadley Wickham
>>     > <h.wickham at gmail.com> wrote:
>>     >>> But, how you propose a warning-to-error transition
>>     >>> should be made without wreaking havoc?  Just flip the
>>     >>> switch in R-devel and see CRAN and Bioconductor packages
>>     >>> break overnight?  Particularly Bioconductor devel might
>>     >>> become non-functional (since at times it requires
>>     >>> R-devel).  For my own code / packages, I would be able
>>     >>> to handle such a change, but I'm completely out of
>>     >>> control if one of the package I'm depending on does not
>>     >>> provide a quick fix (with the only option to remove
>>     >>> package tests for those dependencies).
>>     >>
>>     >> Generally, a package can not be on CRAN if it has any
>>     >> warnings, so I don't think this change would have any
>>     >> impact on CRAN packages.  Isn't this also true for
>>     >> bioconductor?
>>
>>     > Having a tests/warn.R file with:
>>
>>     > warning("boom")
>>
>>     > passes through R CMD check --as-cran unnoticed.
>>
>> Yes, indeed.. you are right Henrik  that many/most R warning()s would
>> not produce  R CMD check  'WARNING's ..
>>
>> I think Hadley and I fell into the same mental pit of concluding
>> that such warning()s  from   if(<length-larger-one>)  ...
>> would not currently happen in CRAN / Bioc packages and hence
>> turning them to errors would not have a direct effect.
>>
>> With your 2nd e-mail of saying that you'd propose such an option
>> only for a few releases of R you've indeed clarified your intent
>> to me.
>> OTOH, I would prefer using an environment variable (as you've
>> proposed as an alternative)  which is turned "active"  at the
>> beginning only manually or  for the  "CRAN incoming" checks of
>> the CRAN team (and bioconductor submission checks?)
>> and later for  '--as-cran'  etc until it eventually becomes the
>> unconditional behavior of R (and the env.variable is no longer used).
>>
>> Martin
>>
>> ______________________________________________
>> R-devel at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-devel
>
>