Check for ALTREP

Author: tlapak

src/assign.c

@@ -497,11 +497,12 @@ SEXP assign(SEXP dt, SEXP rows, SEXP cols, SEXP newcolnames, SEXP values)
     if (length(rows)==0 && targetlen==vlen && (vlen>0 || nrow==0)) {
       if (  MAYBE_SHARED(thisvalue) ||  // set() protects the NAMED of atomic vectors from .Call setting arguments to 2 by wrapping with list
          (TYPEOF(values)==VECSXP && i>LENGTH(values)-1) || // recycled RHS would have columns pointing to others, #185.
-         (TYPEOF(values)!=VECSXP && i>0) // assigning the same values to a second column. Have to ensure a copy #2540
+         (TYPEOF(values)!=VECSXP && i>0) || // assigning the same values to a second column. Have to ensure a copy #2540
+         ALTREP(thisvalue)
          ) {
         if (verbose) {
-          Rprintf(_("RHS for item %d has been duplicated because NAMED==%d MAYBE_SHARED==%d, but then is being plonked. length(values)==%d; length(cols)==%d)\n"),
-                  i+1, NAMED(thisvalue), MAYBE_SHARED(thisvalue), length(values), length(cols));
+          Rprintf(_("RHS for item %d has been duplicated because NAMED==%d MAYBE_SHARED==%d ALTREP==%d, but then is being plonked. length(values)==%d; length(cols)==%d)\n"),
+                  i+1, NAMED(thisvalue), MAYBE_SHARED(thisvalue), ALTREP(thisvalue), length(values), length(cols));
         }
         thisvalue = copyAsPlain(thisvalue);   // PROTECT not needed as assigned as element to protected list below.
       } else {