Lay the ground for Rf_error masking (#1402)

* Add a message at compilation time
* Protect the valid Rf_error calls generated by Rcpp

Author: Enchufa2

ChangeLog

@@ -1,3 +1,13 @@
+2025-11-12 Iñaki Ucar <[email protected]>
+
+	* inst/include/Rcpp/macros/mask.h: Lay the ground for Rf_error masking,
+	unless RCPP_NO_MASK_RF_ERROR is defined; the new define just generates a
+	compilation note, which will become a warning + masking in a future release
+	* inst/include/RcppCommon.h: Include the previous file in the last place
+	* src/attributes.cpp: Use parentheses to protect call to Rf_error
+	* inst/tinytest/cpp/stack.cpp: Idem
+	* inst/tinytest/testRcppInterfaceExporter/src/RcppExports.cpp: Idem
+
 2025-11-04  Dirk Eddelbuettel  <[email protected]>
 
 	* .github/workflows/macos.yaml (jobs): Roll macos-13 to macos-14
@@ -10,7 +20,7 @@
 
 2025-10-21 Iñaki Ucar <[email protected]>
 
-	* inst/include/Rcpp/exceptions_impl.h: use __has_include to simplify checks
+	* inst/include/Rcpp/exceptions_impl.h: Use __has_include to simplify checks
 	to enable demangling, making them robust for more platforms
 
 2025-10-13  Dirk Eddelbuettel  <[email protected]>

inst/include/Rcpp/macros/mask.h

@@ -0,0 +1,33 @@
+// mask.h: Rcpp R/C++ interface class library -- masking macros
+//
+// Copyright (C) 2025        Iñaki Ucar
+//
+// This file is part of Rcpp.
+//
+// Rcpp is free software: you can redistribute it and/or modify it
+// under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 2 of the License, or
+// (at your option) any later version.
+//
+// Rcpp is distributed in the hope that it will be useful, but
+// WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Rcpp.  If not, see <http://www.gnu.org/licenses/>.
+
+#ifndef Rcpp_macros_mask_h
+#define Rcpp_macros_mask_h
+
+#ifndef RCPP_NO_MASK_RF_ERROR
+#define Rf_error(...) \
+    _Pragma("message \"Use of Rf_error() instead of Rcpp::stop(). Calls \
+to Rf_error() in C++ contexts are unsafe: consider using Rcpp::stop() instead, \
+or define RCPP_NO_MASK_RF_ERROR if this is a false positive. More info:\n\
+ - https://github.com/RcppCore/Rcpp/issues/1247\n\
+ - https://github.com/RcppCore/Rcpp/pull/1402\"") \
+    Rf_error(__VA_ARGS__)
+#endif
+
+#endif

inst/include/RcppCommon.h

@@ -4,7 +4,7 @@
 //
 // Copyright (C) 2008 - 2009  Dirk Eddelbuettel
 // Copyright (C) 2009 - 2020  Dirk Eddelbuettel and Romain Francois
-// Copyright (C) 2021         Dirk Eddelbuettel, Romain Francois and Iñaki Ucar
+// Copyright (C) 2021 - 2025  Dirk Eddelbuettel, Romain Francois and Iñaki Ucar
 //
 // This file is part of Rcpp.
 //
@@ -191,4 +191,6 @@ namespace Rcpp {
 
 #include <Rcpp/internal/wrap.h>
 
+#include <Rcpp/macros/mask.h>
+
 #endif

inst/tinytest/cpp/stack.cpp

@@ -2,7 +2,8 @@
 //
 // misc.cpp: Rcpp R/C++ interface class library -- misc unit tests
 //
-// Copyright (C) 2013 - 2022  Dirk Eddelbuettel and Romain Francois
+// Copyright (C) 2013 - 2024  Dirk Eddelbuettel and Romain Francois
+// Copyright (C) 2025         Dirk Eddelbuettel, Romain Francois and Iñaki Ucar
 //
 // This file is part of Rcpp.
 //
@@ -55,7 +56,7 @@ SEXP testSendInterrupt() {
 SEXP maybeThrow(void* data) {
     bool* fail = (bool*) data;
     if (*fail)
-        Rf_error("throw!");
+        (Rf_error)("throw!"); // prevent masking
     else
         return NumericVector::create(42);
 }

inst/tinytest/testRcppInterfaceExporter/src/RcppExports.cpp

@@ -43,7 +43,7 @@ RcppExport SEXP _testRcppInterfaceExporter_test_cpp_interface(SEXP xSEXP, SEXP f
     if (rcpp_isError_gen) {
         SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);
         UNPROTECT(1);
-        Rf_error("%s", CHAR(rcpp_msgSEXP_gen));
+        (Rf_error)("%s", CHAR(rcpp_msgSEXP_gen));
     }
     UNPROTECT(1);
     return rcpp_result_gen;

src/attributes.cpp

@@ -2953,7 +2953,8 @@ namespace attributes {
                      << "    if (rcpp_isError_gen) {" << std::endl
                      << "        SEXP rcpp_msgSEXP_gen = Rf_asChar(rcpp_result_gen);" << std::endl
                      << "        UNPROTECT(1);" << std::endl
-                     << "        Rf_error(\"%s\", CHAR(rcpp_msgSEXP_gen));" << std::endl
+                                 // Parentheses to prevent masking
+                     << "        (Rf_error)(\"%s\", CHAR(rcpp_msgSEXP_gen));" << std::endl
                      << "    }" << std::endl
                      << "    UNPROTECT(1);" << std::endl
                      << "    return rcpp_result_gen;" << std::endl