Further R-devel driven refinement for function-in-namespace lookup

Author: eddelbuettel

ChangeLog

@@ -1,3 +1,8 @@
+2026-04-02  Dirk Eddelbuettel  <edd@debian.org>
+
+	* inst/include/Rcpp/Function.h: Further refinement for 4.6.0 to not
+	require R_NamespaceRegistry, using R_getRegisteredNamespace() instead
+
 2026-04-01  Mattias Ellert  <mattias.ellert@physics.uu.se>
 
 	* inst/discovery/cxx0x.R: Set execute permissions for script

inst/include/Rcpp/Function.h

@@ -69,10 +69,14 @@ namespace Rcpp{
         }
 
         Function_Impl(const std::string& name, const std::string& ns) {
-#if R_VERSION < R_Version(4,5,0)
+#if R_VERSION < R_Version(4,6,0)
             Shield<SEXP> env(Rf_findVarInFrame(R_NamespaceRegistry, Rf_install(ns.c_str())));
+            if (env == R_UnboundValue)
+                stop("there is no namespace called \"%s\"", ns);
 #else
-            Shield<SEXP> env(R_getVarEx(Rf_install(ns.c_str()), R_NamespaceRegistry, FALSE, R_UnboundValue));
+            Shield<SEXP> env(R_getRegisteredNamespace(ns.c_str()));
+            if (env == R_NilValue)
+                stop("there is no namespace called \"%s\"", ns);
 #endif
             if (env == R_UnboundValue) {
                 stop("there is no namespace called \"%s\"", ns);