Make pg adapter use bigserial for pk by default

3 files changed, 62 insertions, 2 deletions

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 6eb7e0ae52..971b274265 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -39,7 +39,7 @@ module ActiveRecord
       self.emulate_booleans = true
 
       NATIVE_DATABASE_TYPES = {
-        primary_key: "BIGINT(8) UNSIGNED DEFAULT NULL auto_increment PRIMARY KEY",
+        primary_key: "BIGINT(8) UNSIGNED auto_increment PRIMARY KEY",
         string:      { name: "varchar", limit: 255 },
         text:        { name: "text", limit: 65535 },
         integer:     { name: "int", limit: 4 },
@@ -736,6 +736,8 @@ module ActiveRecord
         ER_NO_REFERENCED_ROW_2  = 1452
         ER_DATA_TOO_LONG        = 1406
         ER_LOCK_DEADLOCK        = 1213
+        ER_CANNOT_ADD_FOREIGN   = 1215
+        ER_CANNOT_CREATE_TABLE  = 1005
 
         def translate_exception(exception, message)
           case error_number(exception)
@@ -743,6 +745,14 @@ module ActiveRecord
             RecordNotUnique.new(message)
           when ER_NO_REFERENCED_ROW_2
             InvalidForeignKey.new(message)
+          when ER_CANNOT_ADD_FOREIGN
+            mismatched_foreign_key(message)
+          when ER_CANNOT_CREATE_TABLE
+            if message.include?("errno: 150")
+              mismatched_foreign_key(message)
+            else
+              super
+            end
           when ER_DATA_TOO_LONG
             ValueTooLong.new(message)
           when ER_LOCK_DEADLOCK
@@ -914,6 +924,18 @@ module ActiveRecord
           MySQL::TableDefinition.new(*args)
         end
 
+        def mismatched_foreign_key(message)
+          parts = message.scan(/`(\w+)`[ $)]/).flatten
+          MismatchedForeignKey.new(
+            self,
+            message: message,
+            table: parts[0],
+            foreign_key: parts[1],
+            target_table: parts[2],
+            primary_key: parts[3],
+          )
+        end
+
         def extract_schema_qualified_name(string) # :nodoc:
           schema, name = string.to_s.scan(/[^`.\s]+|`[^`]*`/)
           schema, name = @config[:database], schema unless name
diff --git a/activerecord/lib/active_record/errors.rb b/activerecord/lib/active_record/errors.rb
index 6464d40c94..7c8be37326 100644
--- a/activerecord/lib/active_record/errors.rb
+++ b/activerecord/lib/active_record/errors.rb
@@ -123,6 +123,34 @@ module ActiveRecord
   class InvalidForeignKey < WrappedDatabaseException
   end
 
+  # Raised when a foreign key constraint cannot be added because the column type does not match the referenced column type.
+  class MismatchedForeignKey < WrappedDatabaseException
+    def initialize(adapter = nil, message: nil, table: nil, foreign_key: nil, target_table: nil, primary_key: nil)
+      @adapter = adapter
+      if table
+        msg = <<-EOM.strip_heredoc
+          Column `#{foreign_key}` on table `#{table}` has a type of `#{column_type(table, foreign_key)}`.
+          This does not match column `#{primary_key}` on `#{target_table}`, which has type `#{column_type(target_table, primary_key)}`.
+          To resolve this issue, change the type of the `#{foreign_key}` column on `#{table}` to be :integer. (For example `t.integer #{foreign_key}`).
+        EOM
+      else
+        msg = <<-EOM
+          There is a mismatch between the foreign key and primary key column types.
+          Verify that the foreign key column type and the primary key of the associated table match types.
+        EOM
+      end
+      if message
+        msg << "\nOriginal message: #{message}"
+      end
+      super(msg)
+    end
+
+    private
+      def column_type(table, column)
+        @adapter.columns(table).detect { |c| c.name == column }.sql_type
+      end
+  end
+
   # Raised when a record cannot be inserted or updated because a value too long for a column type.
   class ValueTooLong < StatementInvalid
   end
diff --git a/activerecord/lib/active_record/migration/compatibility.rb b/activerecord/lib/active_record/migration/compatibility.rb
index ae45ac7157..9d3652d63b 100644
--- a/activerecord/lib/active_record/migration/compatibility.rb
+++ b/activerecord/lib/active_record/migration/compatibility.rb
@@ -104,11 +104,21 @@ module ActiveRecord
 
       class V5_0 < V5_1
         def create_table(table_name, options = {})
-          if ActiveRecord::Base.connection.adapter_name == "PostgreSQL"
+          connection_name = self.connection.adapter_name
+          if connection_name == "PostgreSQL"
             if options[:id] == :uuid && !options[:default]
               options[:default] = "uuid_generate_v4()"
             end
           end
+
+          # Since 5.1 Postgres adapter uses bigserial type for primary
+          # keys by default and MySQL uses bigint. This compat layer makes old migrations utilize
+          # serial/int type instead -- the way it used to work before 5.1.
+          if options[:id].blank?
+            options[:id] = :integer
+            options[:auto_increment] = true
+          end
+
           super
         end
       end