Allow to assign empty vector or NULL to dimnames

Author: Florian Plaza Oñate

inst/include/Rcpp/vector/DimNameProxy.h

@@ -34,18 +34,25 @@ namespace internal{
             data_(other.data_), dim_(other.dim_) {}
 
         inline DimNameProxy& assign(SEXP other) {
-            SEXP dims = Rf_getAttrib(data_, R_DimSymbol);
-            if (INTEGER(dims)[dim_] != Rf_length(other)) {
-                stop("dimension extent is '%d' while length of names is '%d'", INTEGER(dims)[dim_], Rf_length(other));
-            }
-            SEXP dimnames = Rf_getAttrib(data_, R_DimNamesSymbol);
-            if (Rf_isNull(dimnames)) {
-                Shield<SEXP> new_dimnames(Rf_allocVector(VECSXP, Rf_length(dims)));
-                SET_VECTOR_ELT(new_dimnames, dim_, other);
-                Rf_setAttrib(data_, R_DimNamesSymbol, new_dimnames);
-            } else {
-                SET_VECTOR_ELT(dimnames, dim_, other);
-            }
+			if (Rf_length(other) == 0)
+			{
+				Rf_setAttrib(data_, R_DimNamesSymbol, R_NilValue);
+			} else {
+				SEXP dims = Rf_getAttrib(data_, R_DimSymbol);
+				
+				if (INTEGER(dims)[dim_] != Rf_length(other)) {
+					stop("dimension extent is '%d' while length of names is '%d'", INTEGER(dims)[dim_], Rf_length(other));
+				}
+
+				SEXP dimnames = Rf_getAttrib(data_, R_DimNamesSymbol);
+				if (Rf_isNull(dimnames)) {
+					Shield<SEXP> new_dimnames(Rf_allocVector(VECSXP, Rf_length(dims)));
+					SET_VECTOR_ELT(new_dimnames, dim_, other);
+					Rf_setAttrib(data_, R_DimNamesSymbol, new_dimnames);
+				} else {
+					SET_VECTOR_ELT(dimnames, dim_, other);
+				}
+			}
             return *this;
         }