check for the dummy pointer in CppObject__finalize instead of in R

Author: kevinushey

ChangeLog

@@ -1,9 +1,10 @@
 2026-10-22  Kevin Ushey  <kevinushey@gmail.com>
 
-	* R/Module.R (cpp_refMethods): Make finalize() a no-op for a module
-	object that was never constructed (created without arguments for a class
-	without a default constructor); it used to fail on the dummy pointer, and
-	the failure surfaced as an error message at garbage collection
+	* src/module.cpp (CppObject__finalize): Make finalize() a no-op for a
+	module object that was never constructed (created without arguments for a
+	class without a default constructor); it used to fail on the dummy
+	pointer, and the failure surfaced as an error message at garbage
+	collection
 	* inst/tinytest/test_module.R: Add test
 
 2026-10-22  Michael Sumner <mdsumner@gmail.com>

R/Module.R

@@ -400,18 +400,14 @@ method_wrapper <- function( METHOD, where ){
 ## create a named list of the R methods to invoke C++ methods
 ## from the C++ class with pointer xp
 cpp_refMethods <- function(CLASS, where) {
-    # an object created without arguments for a class lacking a default
-    # constructor holds the dummy pointer (see cpp_object_dummy), which is
-    # not an external pointer: there is nothing to finalize for it
     finalizer <- eval( substitute(
             function(){
-                if( ! identical( .pointer, dummy ) )
-                    .Call( CppObject__finalize, class_pointer , .pointer )
+                .Call( CppObject__finalize, class_pointer , .pointer )
             },
             list(
+                CLASS = CLASS@pointer,
                 CppObject__finalize = CppObject__finalize,
-                class_pointer = CLASS@pointer,
-                dummy = .dummyInstancePointer
+                class_pointer = CLASS@pointer
             )
         ) )
         mets <- c(

src/module.cpp

@@ -108,7 +108,14 @@ RCPP_FUN_4(SEXP, CppField__set, XP_Class cl, SEXP field_xp, SEXP obj, SEXP value
     cl->setProperty(field_xp, obj, value);
     return R_NilValue;
 }
+
+extern SEXP rcpp_dummy_pointer;
+
 RCPP_FUN_2(SEXP, CppObject__finalize, XP_Class cl, SEXP obj) {
+    // an object created without arguments for a class lacking a default
+    // constructor holds the dummy pointer: there is nothing to finalize
+    if (obj == rcpp_dummy_pointer)
+        return R_NilValue;
     cl->run_finalizer(obj);
     return R_NilValue;
 }