Merge pull request #14791 from asn62/mysql_double_bug

Changed extract_limit in class Column to return correct mysql float and
double limits

activerecord/CHANGELOG.md

@@ -1,3 +1,10 @@
+*   Floats with limit >= 25 that get turned into doubles in MySQL no longer have
+    their limit dropped from the schema.
+
+    Fixes #14135.
+
+    *Aaron Nelson*
+
 *   Fix how to calculate associated class name when using namespaced `has_and_belongs_to_many`
     association.
 

activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb

@@ -129,6 +129,8 @@ def extract_limit(sql_type)
           when /^mediumint/i; 3
           when /^smallint/i;  2
           when /^tinyint/i;   1
+          when /^float/i;     24
+          when /^double/i;    53
           else
             super
           end

activerecord/test/cases/adapters/mysql/schema_test.rb

@@ -17,6 +17,44 @@ def setup
           self.table_name = "#{db}.#{table}"
           def self.name; 'Post'; end
         end
+
+        @connection.create_table "mysql_doubles"
+      end
+
+      teardown do
+        @connection.execute "drop table if exists mysql_doubles"
+      end
+
+      class MysqlDouble < ActiveRecord::Base
+        self.table_name = "mysql_doubles"
+      end
+
+      def test_float_limits
+        @connection.add_column :mysql_doubles, :float_no_limit, :float
+        @connection.add_column :mysql_doubles, :float_short, :float, limit: 5
+        @connection.add_column :mysql_doubles, :float_long, :float, limit: 53
+
+        @connection.add_column :mysql_doubles, :float_23, :float, limit: 23
+        @connection.add_column :mysql_doubles, :float_24, :float, limit: 24
+        @connection.add_column :mysql_doubles, :float_25, :float, limit: 25
+        MysqlDouble.reset_column_information
+
+        column_no_limit = MysqlDouble.columns.find { |c| c.name == 'float_no_limit' }
+        column_short = MysqlDouble.columns.find { |c| c.name == 'float_short' }
+        column_long = MysqlDouble.columns.find { |c| c.name == 'float_long' }
+
+        column_23 = MysqlDouble.columns.find { |c| c.name == 'float_23' }
+        column_24 = MysqlDouble.columns.find { |c| c.name == 'float_24' }
+        column_25 = MysqlDouble.columns.find { |c| c.name == 'float_25' }
+
+        # Mysql floats are precision 0..24, Mysql doubles are precision 25..53
+        assert_equal 24, column_no_limit.limit
+        assert_equal 24, column_short.limit
+        assert_equal 53, column_long.limit
+
+        assert_equal 24, column_23.limit
+        assert_equal 24, column_24.limit
+        assert_equal 53, column_25.limit
       end
 
       def test_schema