new test for #1232

Author: eddelbuettel

ChangeLog

@@ -1,3 +1,10 @@
+2022-10-06  Dirk Eddelbuettel  <edd@debian.org>
+
+	* inst/tinytest/test_dataframe.R (test.DataFrame.PushZeroLength): Add
+	new test
+	* inst/tinytest/cpp/DataFrame.cpp (DataFrame_PushOnEmpty): C++
+	support for new test
+
 2022-10-04  Dirk Eddelbuettel  <edd@debian.org>
 
 	* inst/include/Rcpp/DataFrame.h (set_type_after_push): Allow zero-row

inst/tinytest/cpp/DataFrame.cpp

@@ -192,3 +192,17 @@ DataFrame DataFrame_PushZeroLength(){
   df1.push_back(v);
   return df1;
 }
+
+// issue #1232
+// [[Rcpp::export]]
+Rcpp::DataFrame DataFrame_PushOnEmpty() {
+    int n = 0;
+    Rcpp::IntegerVector foo(n);
+    Rcpp::CharacterVector bar(n);
+    Rcpp::CharacterVector baz(n);
+
+    Rcpp::List ll = Rcpp::List::create(Rcpp::Named("foo") = foo,
+                                       Rcpp::Named("bar") = bar);
+    ll.push_back(baz, "baz");
+    return Rcpp::DataFrame(ll);
+}

inst/tinytest/test_dataframe.R

@@ -113,3 +113,7 @@ expect_equal( DataFrame_PushReplicateLength(), df )
 
 #    test.DataFrame.PushZeroLength <- function(){
 expect_warning( DataFrame_PushZeroLength())
+
+## issue #1232: push on empty data.frame
+df <- DataFrame_PushOnEmpty()
+expect_equal(ncol(df), 3L)