dump inherited table options to schema.rb (#42)

* dump inherited table options to schema.rb

* fix for no inherited tables

* dump inherited tables after

* control ordering of dumping

* stree

CHANGELOG.md

@@ -2,12 +2,16 @@
 
 - *Breaking Change* - Support for Ruby 2.7 and Rails 6.1 is dropped
 - *Breaking Change* - The default scoping clause that controls the inherited table SQL construction
-  changes from a where clause using `tableoid`s to using `FROM ONLY`.
-- fixes an issue for Rails 7.1 regarding accessing version table columns through aliased attributes
+  changes from a where clause using `tableoid`s to using `FROM ONLY`
+- Fixes an issue for Rails 7.1 regarding accessing version table columns through aliased attributes
+- Fixes an issue where `Hoardable::RichText` couldn’t be loaded if `ActionText::RichText` wasn’t yet
+  loaded
+- Supports dumping `INHERITS (table_name)` options to `schema.rb` and ensures the inherited tables
+  are dumped after their parents
 
 ## 0.14.3
 
-- The migration template is updated to make the primary key on the versions table its actual primary key.
+- The migration template is updated to make the primary key on the versions table its actual primary key
 
 ## 0.14.2
 

lib/generators/hoardable/install_generator.rb

@@ -11,12 +11,12 @@ class InstallGenerator < Rails::Generators::Base
 
     def create_initializer_file
       create_file("config/initializers/hoardable.rb", <<~TEXT)
-          # Hoardable configuration defaults are below. Learn more at https://github.com/waymondo/hoardable#configuration
-          #
-          # Hoardable.enabled = true
-          # Hoardable.version_updates = true
-          # Hoardable.save_trash = true
-        TEXT
+        # Hoardable configuration defaults are below. Learn more at https://github.com/waymondo/hoardable#configuration
+        #
+        # Hoardable.enabled = true
+        # Hoardable.version_updates = true
+        # Hoardable.save_trash = true
+      TEXT
     end
 
     def create_migration_file

lib/hoardable.rb

@@ -4,6 +4,8 @@
 require "fx"
 require_relative "hoardable/version"
 require_relative "hoardable/arel_visitors"
+require_relative "hoardable/schema_statements"
+require_relative "hoardable/schema_dumper"
 require_relative "hoardable/engine"
 require_relative "hoardable/finder_methods"
 require_relative "hoardable/scopes"

lib/hoardable/engine.rb

@@ -97,5 +97,15 @@ 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
+        # We need to control the table dumping order of tables, so revert these to just +super+
+        Fx::SchemaDumper::Trigger.module_eval("def tables(streams); super; end")
+
+        ActiveRecord::ConnectionAdapters::PostgreSQL::SchemaDumper.prepend(SchemaDumper)
+        ActiveRecord::ConnectionAdapters::PostgreSQL::SchemaStatements.prepend(SchemaStatements)
+      end
+    end
   end
 end

lib/hoardable/schema_dumper.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+module Hoardable
+  module SchemaDumper
+    def ignored?(table_name)
+      super || @connection.inherited_table?(table_name)
+    end
+
+    def tables(stream)
+      super
+      dump_inherited_tables(stream)
+      empty_line(stream)
+      triggers(stream)
+    end
+
+    private def dump_inherited_tables(stream)
+      sorted_tables = @connection.tables.filter { |table| @connection.inherited_table?(table) }.sort
+      sorted_tables.each do |table_name|
+        table(table_name, stream)
+        foreign_keys(table_name, stream)
+      end
+    end
+  end
+  private_constant :SchemaDumper
+end

lib/hoardable/schema_statements.rb

@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+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").presence
+        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
+
+    def inherited_table?(table_name)
+      parent_table_names(table_name).present?
+    end
+  end
+  private_constant :SchemaStatements
+end

test/helper.rb

@@ -9,7 +9,6 @@
 
 $LOAD_PATH.unshift File.expand_path("../lib", __dir__)
 require "hoardable"
-require "fx"
 
 def tmp_dir
   File.expand_path("../tmp", __dir__)

test/test_schema_dumper.rb

@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+require "helper"
+
+class TestSchemaDumper < ActiveSupport::TestCase
+  test "it dumps table inheritance options to schema.rb" do
+    output = dump_table_schema("post_versions")
+    assert_match(<<~SCHEMA.squish, output)
+      create_table \"post_versions\",
+      id: :bigint,
+      default: -> { \"nextval('posts_id_seq'::regclass)\" },
+      options: \"INHERITS (posts)\"
+    SCHEMA
+  end
+
+  test "it does not dump table inheritance options for non inherited table" do
+    output = dump_table_schema("posts")
+    assert_match("create_table \"posts\", force: :cascade do |t|\n", output)
+  end
+
+  test "it dumps inherited table after parent table, and trigger after both" do
+    output = dump_table_schema("post_versions", "posts")
+    assert posts_index = output.index(/create_table "posts"/)
+    assert post_versions_index = output.index(/create_table "post_versions"/)
+    assert(
+      post_versions_trigger_index = output.index(/create_trigger :post_versions_prevent_update/)
+    )
+    assert post_versions_index > posts_index
+    assert post_versions_trigger_index > post_versions_index
+  end
+
+  private def dump_table_schema(*table_names)
+    connection = ActiveRecord::Base.connection
+    ActiveRecord::SchemaDumper.ignore_tables = connection.data_sources - table_names
+    stream = StringIO.new
+    ActiveRecord::SchemaDumper.dump(connection, stream).string
+  end
+end