Fixed issue #1594 (#1596)

Co-authored-by: Matthias Koefferlein <matthias@klayout.de>

src/drc/drc/built-in-macros/_drc_netter.rb

@@ -702,7 +702,8 @@ module DRC
         @l2n = RBA::LayoutToNetlist::new(@engine._dss)
       else
         layout = @engine.source.layout
-        @l2n = RBA::LayoutToNetlist::new(layout.top_cell.name, layout.dbu)
+        cell_name = @engine.source.cell_name
+        @l2n = RBA::LayoutToNetlist::new(cell_name, layout.dbu)
       end
 
       @l2n.name = "DRC"

src/drc/unit_tests/drcSimpleTests.cc

@@ -1617,3 +1617,39 @@ TEST(89_deep_with_mag_cop_size_aniso)
   run_test (_this, "89", true);
 }
 
+TEST(90_issue1594_dual_top)
+{
+  std::string rs = tl::testdata ();
+  rs += "/drc/issue_1594.drc";
+
+  std::string input = tl::testdata ();
+  input += "/drc/issue_1594.gds";
+
+  std::string au = tl::testdata ();
+  au += "/drc/issue_1594_au.cir";
+
+  std::string output = this->tmp_file ("tmp.cir");
+
+  {
+    //  Set some variables
+    lym::Macro config;
+    config.set_text (tl::sprintf (
+        "$drc_force_gc = true\n"
+        "$drc_test_source = '%s'\n"
+        "$drc_test_target = '%s'\n"
+      , input, output)
+    );
+    config.set_interpreter (lym::Macro::Ruby);
+    EXPECT_EQ (config.run (), 0);
+  }
+
+  lym::Macro drc;
+  drc.load_from (rs);
+  EXPECT_EQ (drc.run (), 0);
+
+  //  verify
+
+  CHECKPOINT ();
+  compare_netlists (_this, output, au);
+}
+

testdata/drc/issue_1594.drc

@@ -0,0 +1,15 @@
+source($drc_test_source, "TOP1")
+
+# This is just a smoke test without actual devices
+
+l1 = input(1, 0)
+l2 = input(2, 0)
+l3 = input(3, 0)
+
+connect(l1, l2)
+connect(l2, l3)
+
+writer = RBA::NetlistSpiceWriter::new
+
+netlist.write($drc_test_target, writer, "netlist")
+

testdata/drc/issue_1594_au.cir

@@ -0,0 +1,5 @@
+* netlist
+
+* cell TOP1
+.SUBCKT TOP1
+.ENDS TOP1