Commit 02260ea3 authored by Claude Paroz's avatar Claude Paroz
Browse files

Fixed #24595 -- Prevented loss of null info in MySQL field alteration 

Thanks Simon Percivall for the report, and Simon Charette and Tim
Graham for the reviews.
parent ed336a1a

django/db/backends/base/schema.py

+33 −21
Original line number Diff line number Diff line
@@ -9,9 +9,13 @@ from django.utils.encoding import force_bytes 
logger = logging.getLogger('django.db.backends.schema')





def _related_non_m2m_objects(opts):

    # filters out m2m objects from reverse relations.

    return (obj for obj in opts.related_objects if not obj.field.many_to_many)

def _related_non_m2m_objects(old_field, new_field):

    # Filters out m2m objects from reverse relations.

    # Returns (old_relation, new_relation) tuples.

    return zip(

        (obj for obj in old_field.model._meta.related_objects if not obj.field.many_to_many),

        (obj for obj in new_field.model._meta.related_objects if not obj.field.many_to_many)

    )





class BaseDatabaseSchemaEditor(object):
@@ -454,7 +458,8 @@ class BaseDatabaseSchemaEditor(object): 
        old_type = old_db_params['type']

        new_db_params = new_field.db_parameters(connection=self.connection)

        new_type = new_db_params['type']

        if (old_type is None and old_field.remote_field is None) or (new_type is None and new_field.remote_field is None):

        if ((old_type is None and old_field.remote_field is None) or

                (new_type is None and new_field.remote_field is None)):

            raise ValueError(

                "Cannot alter field %s into %s - they do not properly define "

                "db_type (are you using PostGIS 1.5 or badly-written custom "
@@ -515,10 +520,12 @@ class BaseDatabaseSchemaEditor(object): 
        if old_field.primary_key and new_field.primary_key and old_type != new_type:

            # '_meta.related_field' also contains M2M reverse fields, these

            # will be filtered out

            for rel in _related_non_m2m_objects(new_field.model._meta):

                rel_fk_names = self._constraint_names(rel.related_model, [rel.field.column], foreign_key=True)

            for _old_rel, new_rel in _related_non_m2m_objects(old_field, new_field):

                rel_fk_names = self._constraint_names(

                    new_rel.related_model, [new_rel.field.column], foreign_key=True

                )

                for fk_name in rel_fk_names:

                    self.execute(self._delete_constraint_sql(self.sql_delete_fk, rel.related_model, fk_name))

                    self.execute(self._delete_constraint_sql(self.sql_delete_fk, new_rel.related_model, fk_name))

        # Removed an index? (no strict check, as multiple indexes are possible)

        if (old_field.db_index and not new_field.db_index and

                not old_field.unique and not
@@ -552,7 +559,9 @@ class BaseDatabaseSchemaEditor(object): 
        post_actions = []

        # Type change?

        if old_type != new_type:

            fragment, other_actions = self._alter_column_type_sql(model._meta.db_table, new_field.column, new_type)

            fragment, other_actions = self._alter_column_type_sql(

                model._meta.db_table, old_field, new_field, new_type

            )

            actions.append(fragment)

            post_actions.extend(other_actions)

        # When changing a column NULL constraint to NOT NULL with a given
@@ -669,7 +678,7 @@ class BaseDatabaseSchemaEditor(object): 
        # referring to us.

        rels_to_update = []

        if old_field.primary_key and new_field.primary_key and old_type != new_type:

            rels_to_update.extend(_related_non_m2m_objects(new_field.model._meta))

            rels_to_update.extend(_related_non_m2m_objects(old_field, new_field))

        # Changed to become primary key?

        # Note that we don't detect unsetting of a PK, as we assume another field

        # will always come along and replace it.
@@ -692,20 +701,23 @@ class BaseDatabaseSchemaEditor(object): 
                }

            )

            # Update all referencing columns

            rels_to_update.extend(_related_non_m2m_objects(new_field.model._meta))

            rels_to_update.extend(_related_non_m2m_objects(old_field, new_field))

        # Handle our type alters on the other end of rels from the PK stuff above

        for rel in rels_to_update:

            rel_db_params = rel.field.db_parameters(connection=self.connection)

        for old_rel, new_rel in rels_to_update:

            rel_db_params = new_rel.field.db_parameters(connection=self.connection)

            rel_type = rel_db_params['type']

            fragment, other_actions = self._alter_column_type_sql(

                new_rel.related_model._meta.db_table, old_rel.field, new_rel.field, rel_type

            )

            self.execute(

                self.sql_alter_column % {

                    "table": self.quote_name(rel.related_model._meta.db_table),

                    "changes": self.sql_alter_column_type % {

                        "column": self.quote_name(rel.field.column),

                        "type": rel_type,

                    }

                }

                    "table": self.quote_name(new_rel.related_model._meta.db_table),

                    "changes": fragment[0],

                },

                fragment[1],

            )

            for sql, params in other_actions:

                self.execute(sql, params)

        # Does it have a foreign key?

        if (new_field.remote_field and

                (fks_dropped or not old_field.remote_field or not old_field.db_constraint) and
@@ -740,7 +752,7 @@ class BaseDatabaseSchemaEditor(object): 
        if self.connection.features.connection_persists_old_columns:

            self.connection.close()



    def _alter_column_type_sql(self, table, column, type):

    def _alter_column_type_sql(self, table, old_field, new_field, new_type):

        """

        Hook to specialize column type alteration for different backends,

        for cases when a creation type is different to an alteration type
@@ -753,8 +765,8 @@ class BaseDatabaseSchemaEditor(object): 
        return (

            (

                self.sql_alter_column_type % {

                    "column": self.quote_name(column),

                    "type": type,

                    "column": self.quote_name(new_field.column),

                    "type": new_type,

                },

                [],

            ),

django/db/backends/mysql/schema.py

+8 −0
Original line number Diff line number Diff line
@@ -61,3 +61,11 @@ class DatabaseSchemaEditor(BaseDatabaseSchemaEditor): 
                    # index creation for FKs (index automatically created by MySQL)

                    field.db_index = False

        return super(DatabaseSchemaEditor, self)._model_indexes_sql(model)



    def _alter_column_type_sql(self, table, old_field, new_field, new_type):

        # Keep null property of old field, if it has changed, it will be handled separately

        if old_field.null:

            new_type += " NULL"

        else:

            new_type += " NOT NULL"

        return super(DatabaseSchemaEditor, self)._alter_column_type_sql(table, old_field, new_field, new_type)

django/db/backends/postgresql_psycopg2/schema.py

+6 −3
Original line number Diff line number Diff line
@@ -34,11 +34,12 @@ class DatabaseSchemaEditor(BaseDatabaseSchemaEditor): 
                        model, [field], suffix='_like', sql=self.sql_create_text_index))

        return output



    def _alter_column_type_sql(self, table, column, type):

    def _alter_column_type_sql(self, table, old_field, new_field, new_type):

        """

        Makes ALTER TYPE with SERIAL make sense.

        """

        if type.lower() == "serial":

        if new_type.lower() == "serial":

            column = new_field.column

            sequence_name = "%s_%s_seq" % (table, column)

            return (

                (
@@ -82,4 +83,6 @@ class DatabaseSchemaEditor(BaseDatabaseSchemaEditor): 
                ],

            )

        else:

            return super(DatabaseSchemaEditor, self)._alter_column_type_sql(table, column, type)
 
            return super(DatabaseSchemaEditor, self)._alter_column_type_sql(

                table, old_field, new_field, new_type

            )

docs/releases/1.7.8.txt

+3 −0
Original line number Diff line number Diff line
@@ -10,3 +10,6 @@ Django 1.7.8 fixes: 
  (:ticket:`24637`).



* A database table name quoting regression in 1.7.2 (:ticket:`24605`).



* Prevented the loss of ``null``/``not null`` column properties during field

  alteration of MySQL databases (:ticket:`24595`).

docs/releases/1.8.1.txt

+3 −0
Original line number Diff line number Diff line
@@ -55,3 +55,6 @@ Bugfixes 
  ``qs.annotate(foo=F('field')).values('pk').order_by('foo'))`` (:ticket:`24615`).



* Fixed a database table name quoting regression (:ticket:`24605`).



* Prevented the loss of ``null``/``not null`` column properties during field

  alteration of MySQL databases (:ticket:`24595`).