ROBUSTNESS: Give error if condition for control statements have length != 1 #38
Comments
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The corresponding SVN patch is: Index: src/library/base/man/options.Rd
===================================================================
--- src/library/base/man/options.Rd (revision 72298)
+++ src/library/base/man/options.Rd (working copy)
@@ -86,6 +86,11 @@
vector (atomic or \code{\link{list}}) is extended, by something
like \code{x <- 1:3; x[5] <- 6}.}
+ \item{\code{check.condition}:}{logical, defaulting to \code{FALSE}. If
+ \code{TRUE}, an error is produced whenever the condition to an
+ \code{if} or a \code{while} control statement is of length greater
+ than one. If \code{FALSE}, a \link{warning} is produced.}
+
\item{\code{CBoundsCheck}:}{logical, controlling whether
\code{\link{.C}} and \code{\link{.Fortran}} make copies to check for
array over-runs on the atomic vector arguments.
@@ -445,6 +450,7 @@
\tabular{ll}{
\code{add.smooth} \tab \code{TRUE}\cr
\code{check.bounds} \tab \code{FALSE}\cr
+ \code{check.condition} \tab \code{FALSE}\cr
\code{continue} \tab \code{"+ "}\cr
\code{digits} \tab \code{7}\cr
\code{echo} \tab \code{TRUE}\cr
Index: src/library/utils/R/completion.R
===================================================================
--- src/library/utils/R/completion.R (revision 72298)
+++ src/library/utils/R/completion.R (working copy)
@@ -1304,8 +1304,8 @@
"plt", "ps", "pty", "smo", "srt", "tck", "tcl", "usr",
"xaxp", "xaxs", "xaxt", "xpd", "yaxp", "yaxs", "yaxt")
- options <- c("add.smooth", "browser", "check.bounds", "continue",
- "contrasts", "defaultPackages", "demo.ask", "device",
+ options <- c("add.smooth", "browser", "check.bounds", "check.condition",
+ "continue", "contrasts", "defaultPackages", "demo.ask", "device",
"digits", "dvipscmd", "echo", "editor", "encoding",
"example.ask", "expressions", "help.search.types",
"help.try.all.packages", "htmlhelp", "HTTPUserAgent",
Index: src/main/eval.c
===================================================================
--- src/main/eval.c (revision 72298)
+++ src/main/eval.c (working copy)
@@ -1851,9 +1851,13 @@
Rboolean cond = NA_LOGICAL;
if (length(s) > 1) {
+ int check = asInteger(GetOption1(install("check.condition")));
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(check != NA_INTEGER && check > 0)
+ 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) {
Index: src/main/options.c
===================================================================
--- src/main/options.c (revision 72298)
+++ src/main/options.c (working copy)
@@ -65,6 +65,7 @@
* "timeout" ./connections.c
* "check.bounds"
+ * "check.condition"
* "error"
* "error.messages"
* "show.error.messages"
@@ -248,9 +249,9 @@
char *p;
#ifdef HAVE_RL_COMPLETION_MATCHES
+ PROTECT(v = val = allocList(22));
+#else
PROTECT(v = val = allocList(21));
-#else
- PROTECT(v = val = allocList(20));
#endif
SET_TAG(v, install("prompt"));
@@ -289,6 +290,10 @@
SETCAR(v, ScalarLogical(0)); /* no checking */
v = CDR(v);
+ SET_TAG(v, install("check.condition"));
+ SETCAR(v, ScalarLogical(0)); /* no checking */
+ v = CDR(v);
+
p = getenv("R_KEEP_PKG_SOURCE");
R_KeepSource = (p && (strcmp(p, "yes") == 0)) ? 1 : 0; |
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I've sent an email about this to R-devel 'Control statements with condition with greater than one should give error (not just warning) [PATCH]' on 2017-03-03 (https://mailman.stat.ethz.ch/pipermail/r-devel/2017-March/073817.html) UPDATE: Hmm... what an awkward title - should have been "... condition of length greater than one ..." |
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After feedback in the above R-devel thread, dropping R option PatchNew SVN patch: 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) {Example$ Rscript --vanilla -e "if (1:2 == 1) 1"
[1] 1
Warning message:
In if (1:2 == 1) 1 :
the condition has length > 1 and only the first element will be used
$ _R_CHECK_CONDITION_=true Rscript --vanilla -e "if (1:2 == 1) 1"
Error in if (1:2 == 1) 1 : the condition has length > 1
Execution haltedGit repositoryThe R source with the above patch applied is available in Git repository https://github.com/HenrikBengtsson/r-source/tree/hb-feature/check-condition-env |
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A version of this is now implemented in R devel SVN rev 72358: if (length(s) > 1) {
PROTECT(s); /* needed as per PR#15990. call gets protected by warningcall() */
- warningcall(call,
+ char *check = getenv("_R_CHECK_LENGTH_1_CONDITION_");
+ if((check != NULL) ? StringTrue(check) : FALSE) // warn by default
+ 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);
} |
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Setting |
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Just for the record (since I stumbled upon it), at least one bug in R itself has already been discovered and fixed: Errors caught in other packages: |
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2019-11-25: _R_CHECK_LENGTH_1_CONDITION_=package:_R_CHECK_PACKAGE_NAME_,verboseper https://bugs.r-project.org/bugzilla/show_bug.cgi?id=17658 |
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2022-03-04: R-devel (to become R 4.2.0) will now always give an error whenever |
Any conditions in if statements that have a length of > 1 are considered errors by default since R 4.2.0. Thanks, @HenrikBengtsson! HenrikBengtsson/Wishlist-for-R#38 The value of _R_CHECK_LENGTH_1_CONDITION_ will no longer be checked. This means that regardless of whether the condition is set or not, the command if (c(TRUE, FALSE)) 1 will result in an error.
Issue
Control statements
if(cond)andwhile(cond)in R gives an error iflength(cond) == 0, but iflength(cond) > 1, then only a warning is produced, e.g.By the design of if and while control statements, it makes no sense to use a condition with a length other than one. Because of this there is not logical reason why the above should not be considered an error rather than a warning.
Suggestion
The long-term goal should be that R always produces an error if the length of the condition differs from one. However, due to only a warning has been produces this far, there is a great risk that there exist lots of code that will break immediately if an error is generated. In order to avoid wreaking havoc, a migration from producing a warning to an error may go via an option
check.conditionwith default valueFALSE. WhenFALSE, the current behavior remains and only a warning is produced. WithTRUE, an error is produced.R CMD check --as-crancould enableoptions(check.condition = TRUE)such that all new packages submitted to CRAN must pass this new requirement. This will also allow individual developers to run checks locally.Patch
A complete patch is available in https://github.com/HenrikBengtsson/r-source/compare/hb-develop...HenrikBengtsson:hb-feature/check-condition. Example:
References
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