dump inherited table options to schema.rb

lib/hoardable.rb

@@ -4,6 +4,7 @@
 require "fx"
 require_relative "hoardable/version"
 require_relative "hoardable/arel_visitors"
+require_relative "hoardable/schema_statements"
 require_relative "hoardable/engine"
 require_relative "hoardable/finder_methods"
 require_relative "hoardable/scopes"

lib/hoardable/engine.rb

@@ -97,5 +97,11 @@ class Engine < ::Rails::Engine
         require_relative "encrypted_rich_text" if SUPPORTS_ENCRYPTED_ACTION_TEXT
       end
     end
+
+    initializer "hoardable.schema_statements" do
+      ActiveSupport.on_load(:active_record_postgresqladapter) do
+        ActiveRecord::ConnectionAdapters::PostgreSQL::SchemaStatements.prepend(SchemaStatements)
+      end
+    end
   end
 end

lib/hoardable/schema_statements.rb

@@ -0,0 +1,26 @@
+module Hoardable
+  module SchemaStatements
+    def table_options(table_name)
+      options = super || {}
+      if inherited_table_names = parent_table_names(table_name)
+        options[:options] = "INHERITS (#{inherited_table_names.join(", ")})"
+      end
+      options
+    end
+
+    private def parent_table_names(table_name)
+      scope = quoted_scope(table_name, type: "BASE TABLE")
+
+      query_values(<<~SQL.presence, "SCHEMA")
+        SELECT parent.relname
+        FROM pg_catalog.pg_inherits i
+          JOIN pg_catalog.pg_class child ON i.inhrelid = child.oid
+          JOIN pg_catalog.pg_class parent ON i.inhparent = parent.oid
+          LEFT JOIN pg_namespace n ON n.oid = child.relnamespace
+        WHERE child.relname = #{scope[:name]}
+          AND child.relkind IN (#{scope[:type]})
+          AND n.nspname = #{scope[:schema]}
+      SQL
+    end
+  end
+end

test/test_schema_statements.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+require "helper"
+
+class TestSchemaStatements < ActiveSupport::TestCase
+  test "it dumps table inheritance options to schema.rb" do
+    connection = ActiveRecord::Base.connection
+    ActiveRecord::SchemaDumper.ignore_tables = connection.data_sources - ["post_versions"]
+    stream = StringIO.new
+    output = ActiveRecord::SchemaDumper.dump(connection, stream).string
+    assert_match(<<~SCHEMA.squish, output)
+      create_table \"post_versions\",
+      id: :bigint,
+      default: -> { \"nextval('posts_id_seq'::regclass)\" },
+      options: \"INHERITS (posts)\"
+    SCHEMA
+  end
+end