FEATURE: Added Layout#error_layer.

src/db/db/dbLayoutLayers.cc

@@ -176,10 +176,10 @@ unsigned int
 LayoutLayers::error_layer () const
 {
   if (m_error_layer < 0) {
-    //  create the waste layer (since that layer is cached we can do
+    //  create the error layer (since that layer is cached we can do
     //  this in a "const" fashion.
     db::LayoutLayers *self = const_cast<db::LayoutLayers *> (this);
-    self->m_error_layer = (int) self->insert_special_layer (db::LayerProperties ("WASTE"));
+    self->m_error_layer = (int) self->insert_special_layer (db::LayerProperties ("ERROR"));
   }
 
   return (unsigned int) m_error_layer;

src/db/db/gsiDeclDbLayout.cc

@@ -1670,6 +1670,12 @@ Class<db::Layout> decl_Layout ("db", "Layout",
     "\n"
     "This method has been added in version 0.22.\n"
   ) +
+  gsi::method ("error_layer", &db::Layout::error_layer,
+    "@brief Returns the index of the error layer\n"
+    "The error layer is used to place error texts on it, for example when a PCell evaluation fails.\n"
+    "\n"
+    "This method has been added in version 0.23.13.\n"
+  ) +
   gsi::method ("insert_special_layer", (unsigned int (db::Layout::*) (const db::LayerProperties &)) &db::Layout::insert_special_layer, gsi::arg ("props"),
     "@brief Inserts a new special layer with the given properties\n"
     "\n"

src/db/unit_tests/dbLayoutTests.cc

@@ -795,3 +795,16 @@ TEST(8_MetaInfo)
   EXPECT_EQ (ly.has_context_info (ci), false);
   EXPECT_EQ (ly.meta_info (ci, "a").value.to_string (), "nil");
 }
+
+TEST(9_ErrorLayer)
+{
+  db::Manager m;
+  db::Layout l (&m);
+
+  EXPECT_EQ (l.is_valid_layer (0), false);
+  EXPECT_EQ (l.guiding_shape_layer (), (unsigned int) 0);
+  EXPECT_EQ (l.is_valid_layer (1), false);
+  EXPECT_EQ (l.error_layer (), (unsigned int) 1);
+  EXPECT_EQ (l.is_special_layer (1), true);
+  EXPECT_EQ (int (l.layers ()), 2);
+}