Merge pull request #32299 from davidstosik/expose-fk-ignore-pattern

Expose foreign key name ignore pattern in configuration

6 files changed, 36 insertions, 2 deletions

diff --git a/activerecord/lib/active_record.rb b/activerecord/lib/active_record.rb
index d198466dbf..0e1f315183 100644
--- a/activerecord/lib/active_record.rb
+++ b/activerecord/lib/active_record.rb
@@ -43,6 +43,7 @@ module ActiveRecord
   autoload :DatabaseConfigurations
   autoload :DynamicMatchers
   autoload :Enum
+  autoload :ForeignKeys
   autoload :InternalMetadata
   autoload :Explain
   autoload :Inheritance
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
index 584a86da21..6a498b353c 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
@@ -101,6 +101,10 @@ module ActiveRecord
       end
       alias validated? validate?
 
+      def export_name_on_schema_dump?
+        name !~ ActiveRecord::SchemaDumper.fk_ignore_pattern
+      end
+
       def defined_for?(to_table_ord = nil, to_table: nil, **options)
         if to_table_ord
           self.to_table == to_table_ord.to_s
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index e2147b7fcf..ef45fff9d2 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -1324,7 +1324,7 @@ module ActiveRecord
             identifier = "#{table_name}_#{options.fetch(:column)}_fk"
             hashed_identifier = Digest::SHA256.hexdigest(identifier).first(10)
 
-            "fk_rails_#{hashed_identifier}"
+            "#{ActiveRecord::ForeignKeys::PREFIX}_#{hashed_identifier}"
           end
         end
 
diff --git a/activerecord/lib/active_record/foreign_keys.rb b/activerecord/lib/active_record/foreign_keys.rb
new file mode 100644
index 0000000000..87ce3ace20
--- /dev/null
+++ b/activerecord/lib/active_record/foreign_keys.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module ForeignKeys
+    # The prefix used by Rails to name unnamed foreign keys.
+    PREFIX = "fk_rails"
+
+    # Default regular expression used by Rails to determine if a foreign key
+    # name was generated.
+    DEFAULT_IGNORE_PATTERN = /^#{PREFIX}_[0-9a-f]{10}$/
+  end
+end
diff --git a/activerecord/lib/active_record/schema_dumper.rb b/activerecord/lib/active_record/schema_dumper.rb
index b8d848b999..8fc2752f0c 100644
--- a/activerecord/lib/active_record/schema_dumper.rb
+++ b/activerecord/lib/active_record/schema_dumper.rb
@@ -17,6 +17,12 @@ module ActiveRecord
     # Only strings are accepted if ActiveRecord::Base.schema_format == :sql.
     cattr_accessor :ignore_tables, default: []
 
+    ##
+    # :singleton-method:
+    # Specify a custom regular expression matching foreign keys which name
+    # should not be dumped to db/schema.rb.
+    cattr_accessor :fk_ignore_pattern, default: ActiveRecord::ForeignKeys::DEFAULT_IGNORE_PATTERN
+
     class << self
       def dump(connection = ActiveRecord::Base.connection, stream = STDOUT, config = ActiveRecord::Base)
         connection.create_schema_dumper(generate_options(config)).dump(stream)
@@ -210,7 +216,7 @@ HEADER
               parts << "primary_key: #{foreign_key.primary_key.inspect}"
             end
 
-            if foreign_key.name !~ /^fk_rails_[0-9a-f]{10}$/
+            if foreign_key.export_name_on_schema_dump?
               parts << "name: #{foreign_key.name.inspect}"
             end
 
diff --git a/activerecord/test/cases/migration/foreign_key_test.rb b/activerecord/test/cases/migration/foreign_key_test.rb
index de37215e80..50f5696ad1 100644
--- a/activerecord/test/cases/migration/foreign_key_test.rb
+++ b/activerecord/test/cases/migration/foreign_key_test.rb
@@ -306,6 +306,17 @@ if ActiveRecord::Base.connection.supports_foreign_keys?
           assert_match %r{\s+add_foreign_key "fk_test_has_fk", "fk_test_has_pk", column: "fk_id", primary_key: "pk_id", name: "fk_name"$}, output
         end
 
+        def test_schema_dumping_with_custom_fk_ignore_pattern
+          original_pattern = ActiveRecord::SchemaDumper.fk_ignore_pattern
+          ActiveRecord::SchemaDumper.fk_ignore_pattern = /^ignored_/
+          @connection.add_foreign_key :astronauts, :rockets, name: :ignored_fk_astronauts_rockets
+
+          output = dump_table_schema "astronauts"
+          assert_match %r{\s+add_foreign_key "astronauts", "rockets"$}, output
+
+          ActiveRecord::SchemaDumper.fk_ignore_pattern = original_pattern
+        end
+
         def test_schema_dumping_on_delete_and_on_update_options
           @connection.add_foreign_key :astronauts, :rockets, column: "rocket_id", on_delete: :nullify, on_update: :cascade