Merge pull request #20005 from kamipo/default_expression_support

Add `:expression` option support on the schema default

6 files changed, 36 insertions, 20 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb b/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb
index bcc41acaa1..7e3760d34b 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb
@@ -102,9 +102,13 @@ module ActiveRecord
         quote_table_name("#{table}.#{attr}")
       end
 
-      def quote_default_expression(value, column) #:nodoc:
-        value = lookup_cast_type(column.sql_type).serialize(value)
-        quote(value)
+      def quote_default_expression(value, column) # :nodoc:
+        if value.is_a?(Proc)
+          value.call
+        else
+          value = lookup_cast_type(column.sql_type).serialize(value)
+          quote(value)
+        end
       end
 
       def quoted_true
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_dumper.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_dumper.rb
index 797662d07c..a95109fdae 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_dumper.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_dumper.rb
@@ -76,11 +76,17 @@ module ActiveRecord
       def schema_default(column)
         type = lookup_cast_type_from_column(column)
         default = type.deserialize(column.default)
-        unless default.nil?
+        if default.nil?
+          schema_expression(column)
+        else
           type.type_cast_for_schema(default)
         end
       end
 
+      def schema_expression(column)
+        "-> { #{column.default_function.inspect} }" if column.default_function
+      end
+
       def schema_collation(column)
         column.collation.inspect if column.collation
       end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index d435d91102..3e84786be0 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -495,12 +495,16 @@ module ActiveRecord
       end
 
       # Returns an array of +Column+ objects for the table specified by +table_name+.
-      def columns(table_name)#:nodoc:
+      def columns(table_name) # :nodoc:
         sql = "SHOW FULL FIELDS FROM #{quote_table_name(table_name)}"
         execute_and_free(sql, 'SCHEMA') do |result|
           each_hash(result).map do |field|
             type_metadata = fetch_type_metadata(field[:Type], field[:Extra])
-            new_column(field[:Field], field[:Default], type_metadata, field[:Null] == "YES", nil, field[:Collation])
+            if type_metadata.type == :datetime && field[:Default] == "CURRENT_TIMESTAMP"
+              new_column(field[:Field], nil, type_metadata, field[:Null] == "YES", field[:Default], field[:Collation])
+            else
+              new_column(field[:Field], field[:Default], type_metadata, field[:Null] == "YES", nil, field[:Collation])
+            end
           end
         end
       end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb b/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb
index d5879ea7df..c1c77a967e 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb
@@ -55,10 +55,11 @@ module ActiveRecord
           end
         end
 
-        # Does not quote function default values for UUID columns
-        def quote_default_expression(value, column) #:nodoc:
-          if column.type == :uuid && value =~ /\(\)/
-            value
+        def quote_default_expression(value, column) # :nodoc:
+          if value.is_a?(Proc)
+            value.call
+          elsif column.type == :uuid && value =~ /\(\)/
+            value # Does not quote function default values for UUID columns
           elsif column.respond_to?(:array?)
             value = type_cast_from_column(column, value)
             quote(value)
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_dumper.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_dumper.rb
index a4f0742516..cc7721ddd8 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/schema_dumper.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_dumper.rb
@@ -9,7 +9,7 @@ module ActiveRecord
             spec[:id] = ':bigserial'
           elsif column.type == :uuid
             spec[:id] = ':uuid'
-            spec[:default] = column.default_function.inspect
+            spec[:default] = schema_default(column) || 'nil'
           else
             spec[:id] = column.type.inspect
             spec.merge!(prepare_column_options(column).delete_if { |key, _| [:name, :type, :null].include?(key) })
@@ -41,12 +41,8 @@ module ActiveRecord
           end
         end
 
-        def schema_default(column)
-          if column.default_function
-            column.default_function.inspect unless column.serial?
-          else
-            super
-          end
+        def schema_expression(column)
+          super unless column.serial?
         end
       end
     end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 1c20e4700f..2de6fbfaf0 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -512,8 +512,13 @@ module ActiveRecord
         def extract_value_from_default(default) # :nodoc:
           case default
             # Quoted types
-            when /\A[\(B]?'(.*)'::/m
-              $1.gsub("''".freeze, "'".freeze)
+            when /\A[\(B]?'(.*)'.*::"?([\w. ]+)"?(?:\[\])?\z/m
+              # The default 'now'::date is CURRENT_DATE
+              if $1 == "now".freeze && $2 == "date".freeze
+                nil
+              else
+                $1.gsub("''".freeze, "'".freeze)
+              end
             # Boolean types
             when 'true'.freeze, 'false'.freeze
               default
@@ -535,7 +540,7 @@ module ActiveRecord
         end
 
         def has_default_function?(default_value, default) # :nodoc:
-          !default_value && (%r{\w+\(.*\)} === default)
+          !default_value && (%r{\w+\(.*\)|\(.*\)::\w+} === default)
         end
 
         def load_additional_types(type_map, oids = nil) # :nodoc: