Unify the logic to determine the default schema cache path for a database configuration

When the application has more than one database configuration, only
the primary was being loaded by default on boot time. All the other
connection pools were loading the schema cache lazily.

This logic can be found in:

https://github.com/rails/rails/blob/351a8d9bc99e69cc8d1ced86dc1d523e2dc51985/activerecord/lib/active_record/connection_adapters/pool_config.rb#L13
https://github.com/rails/rails/blob/351a8d9bc99e69cc8d1ced86dc1d523e2dc51985/activerecord/lib/active_record/railtie.rb#L149-L178

The lazy code path wasn't using the same logic to determine the name
of the default schema cache file that the Railties uses, so it
was loading the schema cache of the primary config to all the other
configs. If no table name coincided nothing bad would happen, but if
table names coincided, the schema would be completly wrong in all
non-primary connections.

Author: rafaelfranca

activerecord/lib/active_record/database_configurations/hash_config.rb

@@ -113,8 +113,12 @@ def schema_cache_path
         configuration_hash[:schema_cache_path]
       end
 
-      def default_schema_cache_path
-        "db/schema_cache.yml"
+      def default_schema_cache_path(db_dir = "db")
+        if primary?
+          File.join(db_dir, "schema_cache.yml")
+        else
+          File.join(db_dir, "#{name}_schema_cache.yml")
+        end
       end
 
       def lazy_schema_cache_path

activerecord/lib/active_record/tasks/database_tasks.rb

@@ -439,13 +439,10 @@ def schema_dump_path(db_config, format = ActiveRecord.schema_format)
 
       def cache_dump_filename(db_config_or_name, schema_cache_path: nil)
         if db_config_or_name.is_a?(DatabaseConfigurations::DatabaseConfig)
-          filename = if db_config_or_name.primary?
-            "schema_cache.yml"
-          else
-            "#{db_config_or_name.name}_schema_cache.yml"
-          end
-
-          schema_cache_path || db_config_or_name.schema_cache_path || ENV["SCHEMA_CACHE"] || File.join(ActiveRecord::Tasks::DatabaseTasks.db_dir, filename)
+          schema_cache_path ||
+            db_config_or_name.schema_cache_path ||
+            ENV["SCHEMA_CACHE"] ||
+            db_config_or_name.default_schema_cache_path(ActiveRecord::Tasks::DatabaseTasks.db_dir)
         else
           ActiveRecord.deprecator.deprecation_warning(<<~MSG.squish)
             Passing a database name to `cache_dump_filename` is deprecated and will be removed in Rails 7.3. Pass a

activerecord/test/cases/database_configurations/hash_config_test.rb

@@ -141,11 +141,31 @@ def test_schema_cache_path_default_for_primary
         assert_equal "db/schema_cache.yml", config.default_schema_cache_path
       end
 
+      def test_schema_cache_path_default_for_custom_name
+        config = HashConfig.new("default_env", "alternate", adapter: "abstract")
+        assert_equal "db/alternate_schema_cache.yml", config.default_schema_cache_path
+      end
+
+      def test_schema_cache_path_default_for_different_db_dir
+        config = HashConfig.new("default_env", "alternate", adapter: "abstract")
+        assert_equal "my_db/alternate_schema_cache.yml", config.default_schema_cache_path("my_db")
+      end
+
       def test_schema_cache_path_configuration_hash
         config = HashConfig.new("default_env", "primary", { schema_cache_path: "db/config_schema_cache.yml", adapter: "abstract" })
         assert_equal "db/config_schema_cache.yml", config.schema_cache_path
       end
 
+      def test_lazy_schema_cache_path
+        config = HashConfig.new("default_env", "primary", { schema_cache_path: "db/config_schema_cache.yml", adapter: "abstract" })
+        assert_equal "db/config_schema_cache.yml", config.lazy_schema_cache_path
+      end
+
+      def test_lazy_schema_cache_path_uses_default_if_config_is_not_present
+        config = HashConfig.new("default_env", "alternate", { adapter: "abstract" })
+        assert_equal "db/alternate_schema_cache.yml", config.lazy_schema_cache_path
+      end
+
       def test_validate_checks_the_adapter_exists
         config = HashConfig.new("default_env", "primary", adapter: "abstract")
         assert config.validate!

activerecord/test/cases/tasks/database_tasks_test.rb

@@ -325,6 +325,20 @@ def test_cache_dump_default_filename
       ENV["SCHEMA_CACHE"] = old_path
     end
 
+    def test_cache_dump_default_filename_with_custom_db_dir
+      old_path = ENV["SCHEMA_CACHE"]
+      ENV.delete("SCHEMA_CACHE")
+
+      config = DatabaseConfigurations::HashConfig.new("development", "primary", {})
+
+      ActiveRecord::Tasks::DatabaseTasks.stub(:db_dir, "my_db") do
+        path = ActiveRecord::Tasks::DatabaseTasks.cache_dump_filename(config)
+        assert_equal "my_db/schema_cache.yml", path
+      end
+    ensure
+      ENV["SCHEMA_CACHE"] = old_path
+    end
+
     def test_deprecated_cache_dump_default_filename
       old_path = ENV["SCHEMA_CACHE"]
       ENV.delete("SCHEMA_CACHE")

railties/test/application/rake/multi_dbs_test.rb

@@ -810,9 +810,7 @@ class TwoMigration < ActiveRecord::Migration::Current
         rails "db:drop" rescue nil
       end
 
-      # Note that schema cache loader depends on the connection and
-      # does not work for all connections.
-      test "schema_cache is loaded on primary db in multi-db app" do
+      test "schema_cache is loaded on all connection db in multi-db app if it exists for the connection" do
         require "#{app_path}/config/environment"
         db_migrate_and_schema_cache_dump
 
@@ -822,11 +820,8 @@ class TwoMigration < ActiveRecord::Migration::Current
         cache_tables_a = rails("runner", "p ActiveRecord::Base.connection.schema_cache.columns('books')").strip
         assert_includes cache_tables_a, "title", "expected cache_tables_a to include a title entry"
 
-        expired_warning = capture(:stderr) do
-          cache_size_b = rails("runner", "p AnimalsBase.connection.schema_cache.size", stderr: true).strip
-          assert_equal "0", cache_size_b
-        end
-        assert_match(/Ignoring .*\.yml because it has expired/, expired_warning)
+        cache_size_b = rails("runner", "p AnimalsBase.connection.schema_cache.size", stderr: true).strip
+        assert_equal "12", cache_size_b, "expected the cache size for animals to be valid since it was dumped"
 
         cache_tables_b = rails("runner", "p AnimalsBase.connection.schema_cache.columns('dogs')").strip
         assert_includes cache_tables_b, "name", "expected cache_tables_b to include a name entry"