fk: dump foreign keys at the bottom to make sure tables exist.

2 files changed, 16 insertions, 6 deletions

diff --git a/activerecord/lib/active_record/schema_dumper.rb b/activerecord/lib/active_record/schema_dumper.rb
index 9b46f7751b..84ce725409 100644
--- a/activerecord/lib/active_record/schema_dumper.rb
+++ b/activerecord/lib/active_record/schema_dumper.rb
@@ -91,7 +91,8 @@ HEADER
       end
 
       def tables(stream)
-        @connection.tables.sort.each do |tbl|
+        sorted_tables = @connection.tables.sort
+        sorted_tables.each do |tbl|
           next if ['schema_migrations', ignore_tables].flatten.any? do |ignored|
             case ignored
             when String; remove_prefix_and_suffix(tbl) == ignored
@@ -102,6 +103,13 @@ HEADER
           end
           table(tbl, stream)
         end
+
+        # dump foreign keys at the end to make sure all dependent tables exist.
+        if @connection.supports_foreign_keys?
+          sorted_tables.each do |tbl|
+            foreign_keys(tbl, stream)
+          end
+        end
       end
 
       def table(table, stream)
@@ -171,8 +179,6 @@ HEADER
 
           indexes(table, tbl)
 
-          foreign_keys(table, tbl)
-
           tbl.rewind
           stream.print tbl.read
         rescue => e
@@ -215,8 +221,6 @@ HEADER
       end
 
       def foreign_keys(table, stream)
-        return unless @connection.supports_foreign_keys?
-
         if (foreign_keys = @connection.foreign_keys(table)).any?
           add_foreign_key_statements = foreign_keys.map do |foreign_key|
             parts = [
@@ -233,7 +237,6 @@ HEADER
           end
 
           stream.puts add_foreign_key_statements.sort.join("\n")
-          stream.puts
         end
       end
 
diff --git a/activerecord/test/cases/schema_dumper_test.rb b/activerecord/test/cases/schema_dumper_test.rb
index b1e7420c66..4e71d04bc0 100644
--- a/activerecord/test/cases/schema_dumper_test.rb
+++ b/activerecord/test/cases/schema_dumper_test.rb
@@ -372,6 +372,13 @@ class SchemaDumperTest < ActiveRecord::TestCase
     assert_match %r{create_table "subscribers", id: false}, output
   end
 
+  if ActiveRecord::Base.connection.supports_foreign_keys?
+    def test_foreign_keys_are_dumped_at_the_bottom_to_circumvent_dependency_issues
+      output = standard_dump
+      assert_match(/^\s+add_foreign_key "fk_test_has_fk"[^\n]+\n\s+add_foreign_key "lessons_students"/, output)
+    end
+  end
+
   class CreateDogMigration < ActiveRecord::Migration
     def up
       create_table("dog_owners") do |t|