From e01c18e815d4d3e1067fd3bcf4494c95257ac29b Mon Sep 17 00:00:00 2001
From: Chris Ward <chris.ward@teamnorthwoods.com>
Date: Sat, 30 Sep 2023 12:05:19 -0400
Subject: [PATCH] fix for virtual column definition - bring in
 https://github.com/rails/rails/commit/7fa2720b09e044c79764329e3f0a23aab13ffb89

---
 .../postgis/schema_statements.rb                  |  7 ++++++-
 test/cases/ddl_test.rb                            | 15 +++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/lib/active_record/connection_adapters/postgis/schema_statements.rb b/lib/active_record/connection_adapters/postgis/schema_statements.rb
index 4e092997..46c50477 100644
--- a/lib/active_record/connection_adapters/postgis/schema_statements.rb
+++ b/lib/active_record/connection_adapters/postgis/schema_statements.rb
@@ -11,7 +11,12 @@ def new_column_from_field(table_name, field)
           column_name, type, default, notnull, oid, fmod, collation, comment, attgenerated = field
           type_metadata = fetch_type_metadata(column_name, type, oid.to_i, fmod.to_i)
           default_value = extract_value_from_default(default)
-          default_function = extract_default_function(default_value, default)
+
+          if attgenerated.present?
+            default_function = default
+          else
+            default_function = extract_default_function(default_value, default)
+          end
 
           if match = default_function&.match(/\Anextval\('"?(?<sequence_name>.+_(?<suffix>seq\d*))"?'::regclass\)\z/)
             serial = sequence_name_from_parts(table_name, column_name, match[:suffix]) == match[:sequence_name]
diff --git a/test/cases/ddl_test.rb b/test/cases/ddl_test.rb
index 9cfa9a93..dc501af5 100644
--- a/test/cases/ddl_test.rb
+++ b/test/cases/ddl_test.rb
@@ -307,6 +307,20 @@ def test_column_defaults
       assert_equal(-1, klass.new.sample_integer)
     end
 
+    # Ensure virtual column default function works like the Postgres adapter.
+    def test_virtual_column_default_function
+      skip "Virtual Columns are not supported in this version of PostGIS" unless SpatialModel.connection.supports_virtual_columns?
+      klass.connection.create_table(:spatial_models, force: true) do |t|
+        t.integer :column1
+        t.virtual :column2, type: :integer, as: "(column1 + 1)", stored: true
+      end
+      klass.reset_column_information
+      col = klass.columns.last
+      assert_equal(:integer, col.type)
+      assert_equal("(column1 + 1)", col.default_function)
+      assert(col.virtual?)
+    end
+
     def test_column_types
       klass.connection.create_table(:spatial_models, force: true) do |t|
         t.column "sample_integer", :integer
@@ -364,6 +378,7 @@ def test_generated_geometry_column
       end
       klass.reset_column_information
       col = klass.columns.last
+      assert_equal("st_buffer(coordinates, (10)::double precision)", col.default_function)
       assert_equal(:geometry, col.type)
       assert(col.virtual?)
     end