convert c++ exceptions to r errors in module .External entry points (#1496)

Author: kevinushey

ChangeLog

@@ -1,5 +1,12 @@
 2026-08-03  Kevin Ushey  <kevinushey@gmail.com>
 
+	* src/module.cpp (class__newInstance, CppMethod__invoke,
+	CppMethod__invoke_void, CppMethod__invoke_notvoid): Convert C++
+	exceptions to R errors at these .External entry points, so that
+	e.g. calling a method on an uninitialized module object raises
+	the intended R error rather than terminating the R session
+	(#1495)
+	* inst/tinytest/test_module.R: Add regression test
 	* inst/include/Rcpp/module/class.h (invoke): Protect freshly
 	computed method results while wrapping them in the result list
 	(#1493)

inst/tinytest/test_module.R

@@ -102,6 +102,12 @@ x10 <- runif(10, 10.0, 20.0)
 set.seed(123)
 expect_equal(r$get(10), x10)
 
+## calling a method on an uninitialized module object (created via the
+## dummy-object path for classes without a default constructor) should
+## raise an R error rather than terminating the R session (#1495)
+r <- new( ModuleRandomizer )
+expect_error( r$get(10L), "not initialized" )
+
 #    test.Module.flexible.semantics <- function( ){
 expect_equal( test_reference( seq(0,10) ), 11L )
 expect_equal( test_const_reference( seq(0,10) ), 11L )

src/module.cpp

@@ -135,12 +135,14 @@ END_RCPP
 }														// #nocov end
 
 SEXP class__newInstance(SEXP args) {
+BEGIN_RCPP
     SEXP p = CDR(args);
 
     XP_Module module(CAR(p)); p = CDR(p);
     XP_Class clazz(CAR(p)); p = CDR(p);
     UNPACK_EXTERNAL_ARGS(cargs,p)
     return clazz->newInstance(cargs, nargs);
+END_RCPP
 }
 
 // relies on being set in .onLoad()
@@ -164,6 +166,7 @@ SEXP class__dummyInstance(SEXP args) {
 }
 
 SEXP CppMethod__invoke(SEXP args) {						// #nocov start
+BEGIN_RCPP
     SEXP p = CDR(args);
 
     // the external pointer to the class
@@ -180,9 +183,11 @@ SEXP CppMethod__invoke(SEXP args) {						// #nocov start
     UNPACK_EXTERNAL_ARGS(cargs,p)
 
     return clazz->invoke(met, obj, cargs, nargs);
-}														// #nocov end 
+END_RCPP
+}														// #nocov end
 
 SEXP CppMethod__invoke_void(SEXP args) {
+BEGIN_RCPP
     SEXP p = CDR(args);
 
     // the external pointer to the class
@@ -199,9 +204,11 @@ SEXP CppMethod__invoke_void(SEXP args) {
     UNPACK_EXTERNAL_ARGS(cargs,p)
     clazz->invoke_void(met, obj, cargs, nargs);
     return R_NilValue;
+END_RCPP
 }
 
 SEXP CppMethod__invoke_notvoid(SEXP args) {
+BEGIN_RCPP
     SEXP p = CDR(args);
 
     // the external pointer to the class
@@ -218,6 +225,7 @@ SEXP CppMethod__invoke_notvoid(SEXP args) {
     UNPACK_EXTERNAL_ARGS(cargs,p)
 
     return clazz->invoke_notvoid(met, obj, cargs, nargs);
+END_RCPP
 }
 
 namespace Rcpp{