Allow `truncate` for SQLite3 adapter and add `rails db:seed:replant` (#34779)

* Add `ActiveRecord::Base.connection.truncate` for SQLite3 adapter.

SQLite doesn't support `TRUNCATE TABLE`, but SQLite3 adapter can support
`ActiveRecord::Base.connection.truncate` by using `DELETE FROM`.

`DELETE` without `WHERE` uses "The Truncate Optimization",
see https://www.sqlite.org/lang_delete.html.

* Add `rails db:seed:replant` that truncates database tables and loads the seeds

Closes #34765

1 files changed, 121 insertions, 1 deletions

diff --git a/railties/test/application/rake/dbs_test.rb b/railties/test/application/rake/dbs_test.rb
index ba5704c53e..a8ec1f3663 100644
--- a/railties/test/application/rake/dbs_test.rb
+++ b/railties/test/application/rake/dbs_test.rb
@@ -1,11 +1,12 @@
 # frozen_string_literal: true
 
 require "isolation/abstract_unit"
+require "env_helpers"
 
 module ApplicationTests
   module RakeTests
     class RakeDbsTest < ActiveSupport::TestCase
-      include ActiveSupport::Testing::Isolation
+      include ActiveSupport::Testing::Isolation, EnvHelpers
 
       def setup
         build_app
@@ -139,6 +140,59 @@ module ApplicationTests
         end
       end
 
+      test "db:truncate_all truncates all not internal tables" do
+        Dir.chdir(app_path) do
+          rails "generate", "model", "book", "title:string"
+          rails "db:migrate"
+          require "#{app_path}/config/environment"
+          Book.create!(title: "Remote")
+          assert_equal 1, Book.count
+          schema_migrations = ActiveRecord::Base.connection.execute("SELECT * from \"#{ActiveRecord::Base.schema_migrations_table_name}\"")
+          internal_metadata = ActiveRecord::Base.connection.execute("SELECT * from \"#{ActiveRecord::Base.internal_metadata_table_name}\"")
+
+          rails "db:truncate_all"
+
+          assert_equal(
+            schema_migrations,
+            ActiveRecord::Base.connection.execute("SELECT * from \"#{ActiveRecord::Base.schema_migrations_table_name}\"")
+          )
+          assert_equal(
+            internal_metadata,
+            ActiveRecord::Base.connection.execute("SELECT * from \"#{ActiveRecord::Base.internal_metadata_table_name}\"")
+          )
+          assert_equal 0, Book.count
+        end
+      end
+
+      test "db:truncate_all does not truncate any tables when environment is protected" do
+        with_rails_env "production" do
+          Dir.chdir(app_path) do
+            rails "generate", "model", "book", "title:string"
+            rails "db:migrate"
+            require "#{app_path}/config/environment"
+            Book.create!(title: "Remote")
+            assert_equal 1, Book.count
+            schema_migrations = ActiveRecord::Base.connection.execute("SELECT * from \"#{ActiveRecord::Base.schema_migrations_table_name}\"")
+            internal_metadata = ActiveRecord::Base.connection.execute("SELECT * from \"#{ActiveRecord::Base.internal_metadata_table_name}\"")
+            books = ActiveRecord::Base.connection.execute("SELECT * from \"books\"")
+
+            output = rails("db:truncate_all", allow_failure: true)
+            assert_match(/ActiveRecord::ProtectedEnvironmentError/, output)
+
+            assert_equal(
+              schema_migrations,
+              ActiveRecord::Base.connection.execute("SELECT * from \"#{ActiveRecord::Base.schema_migrations_table_name}\"")
+            )
+            assert_equal(
+              internal_metadata,
+              ActiveRecord::Base.connection.execute("SELECT * from \"#{ActiveRecord::Base.internal_metadata_table_name}\"")
+            )
+            assert_equal 1, Book.count
+            assert_equal(books, ActiveRecord::Base.connection.execute("SELECT * from \"books\""))
+          end
+        end
+      end
+
       def db_migrate_and_status(expected_database)
         rails "generate", "model", "book", "title:string"
         rails "db:migrate"
@@ -387,6 +441,72 @@ module ApplicationTests
 
         assert_equal "test", test_environment.call
       end
+
+      test "db:seed:replant truncates all not internal tables and loads the seeds" do
+        Dir.chdir(app_path) do
+          rails "generate", "model", "book", "title:string"
+          rails "db:migrate"
+          require "#{app_path}/config/environment"
+          Book.create!(title: "Remote")
+          assert_equal 1, Book.count
+          schema_migrations = ActiveRecord::Base.connection.execute("SELECT * from \"#{ActiveRecord::Base.schema_migrations_table_name}\"")
+          internal_metadata = ActiveRecord::Base.connection.execute("SELECT * from \"#{ActiveRecord::Base.internal_metadata_table_name}\"")
+
+          app_file "db/seeds.rb", <<-RUBY
+            Book.create!(title: "Rework")
+            Book.create!(title: "Ruby Under a Microscope")
+          RUBY
+
+          rails "db:seed:replant"
+
+          assert_equal(
+            schema_migrations,
+            ActiveRecord::Base.connection.execute("SELECT * from \"#{ActiveRecord::Base.schema_migrations_table_name}\"")
+          )
+          assert_equal(
+            internal_metadata,
+            ActiveRecord::Base.connection.execute("SELECT * from \"#{ActiveRecord::Base.internal_metadata_table_name}\"")
+          )
+          assert_equal 2, Book.count
+          assert_not_predicate Book.where(title: "Remote"), :exists?
+          assert_predicate Book.where(title: "Rework"), :exists?
+          assert_predicate Book.where(title: "Ruby Under a Microscope"), :exists?
+        end
+      end
+
+      test "db:seed:replant does not truncate any tables and does not load the seeds when environment is protected" do
+        with_rails_env "production" do
+          Dir.chdir(app_path) do
+            rails "generate", "model", "book", "title:string"
+            rails "db:migrate"
+            require "#{app_path}/config/environment"
+            Book.create!(title: "Remote")
+            assert_equal 1, Book.count
+            schema_migrations = ActiveRecord::Base.connection.execute("SELECT * from \"#{ActiveRecord::Base.schema_migrations_table_name}\"")
+            internal_metadata = ActiveRecord::Base.connection.execute("SELECT * from \"#{ActiveRecord::Base.internal_metadata_table_name}\"")
+            books = ActiveRecord::Base.connection.execute("SELECT * from \"books\"")
+
+            app_file "db/seeds.rb", <<-RUBY
+              Book.create!(title: "Rework")
+            RUBY
+
+            output = rails("db:seed:replant", allow_failure: true)
+            assert_match(/ActiveRecord::ProtectedEnvironmentError/, output)
+
+            assert_equal(
+              schema_migrations,
+              ActiveRecord::Base.connection.execute("SELECT * from \"#{ActiveRecord::Base.schema_migrations_table_name}\"")
+            )
+            assert_equal(
+              internal_metadata,
+              ActiveRecord::Base.connection.execute("SELECT * from \"#{ActiveRecord::Base.internal_metadata_table_name}\"")
+            )
+            assert_equal 1, Book.count
+            assert_equal(books, ActiveRecord::Base.connection.execute("SELECT * from \"books\""))
+            assert_not_predicate Book.where(title: "Rework"), :exists?
+          end
+        end
+      end
     end
   end
 end