Stop fetch_all_Transcripts returning an empty list when there aren't any...

Stop fetch_all_Transcripts returning an empty list when there aren't any transcripts. The old behaviour was to return undef

modules/Bio/EnsEMBL/Gene.pm

@@ -1013,8 +1013,12 @@ sub get_all_Transcripts {
       $self->{'_transcript_array'} = $transcripts;
     }
   }
-  my @array_copy = @{ $self->{'_transcript_array'} };
-  return \@array_copy;
+  my @array_copy;
+  if (defined $self->{'_transcript_array'}) {
+    @array_copy = @{ $self->{'_transcript_array'} } ;
+    return \@array_copy;
+  }
+  return;
 }
 
 

modules/Bio/EnsEMBL/Utils/TranscriptSelector.pm

@@ -104,7 +104,7 @@ sub select_canonical_transcript_for_Gene {
         @transcripts = @$transcript_array;
     } else {
         warning('No transcripts attached to gene '.$gene->stable_id);
-        return undef;
+        return;
     }
     my @encoded; # array of encoded transcripts