Commit 50328f0a authored by Anssi Kääriäinen's avatar Anssi Kääriäinen
Browse files

Fixed #19861 -- Transaction ._dirty flag improvement 

There were a couple of errors in ._dirty flag handling:
  * It started as None, but was never reset to None.
  * The _dirty flag was sometimes used to indicate if the connection
    was inside transaction management, but this was not done
    consistently. This also meant the flag had three separate values.
  * The None value had a special meaning, causing for example inability
    to commit() on new connection unless enter/leave tx management was
    done.
  * The _dirty was tracking "connection in transaction" state, but only
    in managed transactions.
  * Some tests never reset the transaction state of the used connection.
  * And some additional less important changes.

This commit has some potential for regressions, but as the above list
shows, the current situation isn't perfect either.
parent 21089416

django/db/backends/__init__.py

+18 −25
Original line number Diff line number Diff line
@@ -41,7 +41,10 @@ class BaseDatabaseWrapper(object): 
        # Transaction related attributes

        self.transaction_state = []

        self.savepoint_state = 0

        self._dirty = None

        # Tracks if the connection is believed to be in transaction. This is

        # set somewhat aggressively, as the DBAPI doesn't make it easy to

        # deduce if the connection is in transaction or not.

        self._dirty = False

        self._thread_ident = thread.get_ident()

        self.allow_thread_sharing = allow_thread_sharing
@@ -118,8 +121,7 @@ class BaseDatabaseWrapper(object): 
        stack.

        """

        if self._dirty:

            self._rollback()

            self._dirty = False

            self.rollback()

        while self.transaction_state:

            self.leave_transaction_management()
@@ -137,9 +139,6 @@ class BaseDatabaseWrapper(object): 
            self.transaction_state.append(self.transaction_state[-1])

        else:

            self.transaction_state.append(settings.TRANSACTIONS_MANAGED)



        if self._dirty is None:

            self._dirty = False

        self._enter_transaction_management(managed)



    def leave_transaction_management(self):
@@ -153,14 +152,16 @@ class BaseDatabaseWrapper(object): 
        else:

            raise TransactionManagementError(

                "This code isn't under transaction management")

        # The _leave_transaction_management hook can change the dirty flag,

        # so memoize it.

        dirty = self._dirty

        # We will pass the next status (after leaving the previous state

        # behind) to subclass hook.

        self._leave_transaction_management(self.is_managed())

        if self._dirty:

        if dirty:

            self.rollback()

            raise TransactionManagementError(

                "Transaction managed block ended with pending COMMIT/ROLLBACK")

        self._dirty = False



    def validate_thread_sharing(self):

        """
@@ -190,11 +191,7 @@ class BaseDatabaseWrapper(object): 
        to decide in a managed block of code to decide whether there are open

        changes waiting for commit.

        """

        if self._dirty is not None:

        self._dirty = True

        else:

            raise TransactionManagementError("This code isn't under transaction "

                "management")



    def set_clean(self):

        """
@@ -202,10 +199,7 @@ class BaseDatabaseWrapper(object): 
        to decide in a managed block of code to decide whether a commit or rollback

        should happen.

        """

        if self._dirty is not None:

        self._dirty = False

        else:

            raise TransactionManagementError("This code isn't under transaction management")

        self.clean_savepoints()



    def clean_savepoints(self):
@@ -233,8 +227,7 @@ class BaseDatabaseWrapper(object): 
        if top:

            top[-1] = flag

            if not flag and self.is_dirty():

                self._commit()

                self.set_clean()

                self.commit()

        else:

            raise TransactionManagementError("This code isn't under transaction "

                "management")
@@ -245,7 +238,7 @@ class BaseDatabaseWrapper(object): 
        """

        self.validate_thread_sharing()

        if not self.is_managed():

            self._commit()

            self.commit()

            self.clean_savepoints()

        else:

            self.set_dirty()
@@ -256,7 +249,7 @@ class BaseDatabaseWrapper(object): 
        """

        self.validate_thread_sharing()

        if not self.is_managed():

            self._rollback()

            self.rollback()

        else:

            self.set_dirty()
@@ -343,6 +336,7 @@ class BaseDatabaseWrapper(object): 
        if self.connection is not None:

            self.connection.close()

            self.connection = None

        self.set_clean()



    def cursor(self):

        self.validate_thread_sharing()
@@ -485,14 +479,13 @@ class BaseDatabaseFeatures(object): 
            self.connection.managed(True)

            cursor = self.connection.cursor()

            cursor.execute('CREATE TABLE ROLLBACK_TEST (X INT)')

            self.connection._commit()

            self.connection.commit()

            cursor.execute('INSERT INTO ROLLBACK_TEST (X) VALUES (8)')

            self.connection._rollback()

            self.connection.rollback()

            cursor.execute('SELECT COUNT(X) FROM ROLLBACK_TEST')

            count, = cursor.fetchone()

            cursor.execute('DROP TABLE ROLLBACK_TEST')

            self.connection._commit()

            self.connection._dirty = False

            self.connection.commit()

        finally:

            self.connection.leave_transaction_management()

        return count == 0

django/db/backends/creation.py

+1 −1
Original line number Diff line number Diff line
@@ -385,8 +385,8 @@ class BaseDatabaseCreation(object): 
        # Create the test database and connect to it. We need to autocommit

        # if the database supports it because PostgreSQL doesn't allow

        # CREATE/DROP DATABASE statements within transactions.

        cursor = self.connection.cursor()

        self._prepare_for_test_db_ddl()

        cursor = self.connection.cursor()

        try:

            cursor.execute(

                "CREATE DATABASE %s %s" % (qn(test_database_name), suffix))

django/db/backends/postgresql_psycopg2/base.py

+9 −0
Original line number Diff line number Diff line
@@ -149,6 +149,8 @@ class DatabaseWrapper(BaseDatabaseWrapper): 
                exc_info=sys.exc_info()

            )

            raise

        finally:

            self.set_clean()



    @cached_property

    def pg_version(self):
@@ -233,10 +235,17 @@ class DatabaseWrapper(BaseDatabaseWrapper): 
        try:

            if self.connection is not None:

                self.connection.set_isolation_level(level)

            if level == psycopg2.extensions.ISOLATION_LEVEL_AUTOCOMMIT:

                self.set_clean()

        finally:

            self.isolation_level = level

            self.features.uses_savepoints = bool(level)



    def set_dirty(self):

        if ((self.transaction_state and self.transaction_state[-1]) or

                not self.features.uses_autocommit):

            super(DatabaseWrapper, self).set_dirty()



    def _commit(self):

        if self.connection is not None:

            try:

django/db/backends/postgresql_psycopg2/creation.py

+2 −0
Original line number Diff line number Diff line
@@ -82,6 +82,8 @@ class DatabaseCreation(BaseDatabaseCreation): 


    def _prepare_for_test_db_ddl(self):

        """Rollback and close the active transaction."""

        # Make sure there is an open connection.

        self.connection.cursor()

        self.connection.connection.rollback()

        self.connection.connection.set_isolation_level(

                psycopg2.extensions.ISOLATION_LEVEL_AUTOCOMMIT)

django/db/backends/util.py

+3 −7
Original line number Diff line number Diff line
@@ -19,13 +19,9 @@ class CursorWrapper(object): 
        self.cursor = cursor

        self.db = db



    def set_dirty(self):

        if self.db.is_managed():

            self.db.set_dirty()



    def __getattr__(self, attr):

        if attr in ('execute', 'executemany', 'callproc'):

            self.set_dirty()

            self.db.set_dirty()

        return getattr(self.cursor, attr)



    def __iter__(self):
@@ -35,7 +31,7 @@ class CursorWrapper(object): 
class CursorDebugWrapper(CursorWrapper):



    def execute(self, sql, params=()):

        self.set_dirty()

        self.db.set_dirty()

        start = time()

        try:

            return self.cursor.execute(sql, params)
@@ -52,7 +48,7 @@ class CursorDebugWrapper(CursorWrapper): 
            )



    def executemany(self, sql, param_list):

        self.set_dirty()

        self.db.set_dirty()

        start = time()

        try:

            return self.cursor.executemany(sql, param_list)