work with sqlalchemy 1.4 immutable URL object

Author: davidism

CHANGES.rst

@@ -1,3 +1,13 @@
+Version 2.5
+-----------
+
+Unreleased
+
+-   Update to support SQLAlchemy 1.4.
+-   SQLAlchemy ``URL`` objects are immutable. Some internal methods have
+    changed to return a new URL instead of ``None``. :issue:`885`
+
+
 Version 2.4.4
 -------------
 

flask_sqlalchemy/__init__.py

@@ -40,6 +40,26 @@
 before_models_committed = _signals.signal('before-models-committed')
 
 
+def _sa_url_set(url, **kwargs):
+    try:
+        url = url.set(**kwargs)
+    except AttributeError:
+        # SQLAlchemy <= 1.3
+        for key, value in kwargs.items():
+            setattr(url, key, value)
+
+    return url
+
+
+def _sa_url_query_setdefault(url, **kwargs):
+    query = dict(url.query)
+
+    for key, value in kwargs.items():
+        query.setdefault(key, value)
+
+    return _sa_url_set(url, query=query)
+
+
 def _make_table(db):
     def _make_table(*args, **kwargs):
         if len(args) > 1 and isinstance(args[1], db.Column):
@@ -552,7 +572,7 @@ def get_engine(self):
                 return self._engine
 
             sa_url = make_url(uri)
-            options = self.get_options(sa_url, echo)
+            sa_url, options = self.get_options(sa_url, echo)
             self._engine = rv = self._sa.create_engine(sa_url, options)
 
             if _record_queries(self._app):
@@ -566,8 +586,9 @@ def get_engine(self):
     def get_options(self, sa_url, echo):
         options = {}
 
-        self._sa.apply_pool_defaults(self._app, options)
-        self._sa.apply_driver_hacks(self._app, sa_url, options)
+        options = self._sa.apply_pool_defaults(self._app, options)
+        sa_url, options = self._sa.apply_driver_hacks(self._app, sa_url, options)
+
         if echo:
             options['echo'] = echo
 
@@ -578,7 +599,7 @@ def get_options(self, sa_url, echo):
         # Give options set in SQLAlchemy.__init__() ultimate priority
         options.update(self._sa._engine_options)
 
-        return options
+        return sa_url, options
 
 
 def get_state(app):
@@ -861,6 +882,11 @@ def shutdown_session(response_or_exc):
             return response_or_exc
 
     def apply_pool_defaults(self, app, options):
+        """
+        .. versionchanged:: 2.5
+            Returns the ``options`` dict, for consistency with
+            :meth:`apply_driver_hacks`.
+        """
         def _setdefault(optionkey, configkey):
             value = app.config[configkey]
             if value is not None:
@@ -869,6 +895,7 @@ def _setdefault(optionkey, configkey):
         _setdefault('pool_timeout', 'SQLALCHEMY_POOL_TIMEOUT')
         _setdefault('pool_recycle', 'SQLALCHEMY_POOL_RECYCLE')
         _setdefault('max_overflow', 'SQLALCHEMY_MAX_OVERFLOW')
+        return options
 
     def apply_driver_hacks(self, app, sa_url, options):
         """This method is called before engine creation and used to inject
@@ -879,9 +906,15 @@ def apply_driver_hacks(self, app, sa_url, options):
         The default implementation provides some saner defaults for things
         like pool sizes for MySQL and sqlite.  Also it injects the setting of
         `SQLALCHEMY_NATIVE_UNICODE`.
+
+        .. versionchanged:: 2.5
+            Returns ``(sa_url, options)``. SQLAlchemy 1.4 made the URL
+            immutable, so any changes to it must now be passed back up
+            to the original caller.
         """
         if sa_url.drivername.startswith('mysql'):
-            sa_url.query.setdefault('charset', 'utf8')
+            sa_url = _sa_url_query_setdefault(sa_url, charset="utf8")
+
             if sa_url.drivername != 'mysql+gaerdbms':
                 options.setdefault('pool_size', 10)
                 options.setdefault('pool_recycle', 7200)
@@ -911,7 +944,9 @@ def apply_driver_hacks(self, app, sa_url, options):
 
             # if it's not an in memory database we make the path absolute.
             if not detected_in_memory:
-                sa_url.database = os.path.join(app.root_path, sa_url.database)
+                sa_url = _sa_url_set(
+                    sa_url, database=os.path.join(app.root_path, sa_url.database)
+                )
 
         unu = app.config['SQLALCHEMY_NATIVE_UNICODE']
         if unu is None:
@@ -932,6 +967,8 @@ def apply_driver_hacks(self, app, sa_url, options):
                 DeprecationWarning
             )
 
+        return sa_url, options
+
     @property
     def engine(self):
         """Gives access to the engine.  If the database configuration is bound

tests/test_config.py

@@ -1,3 +1,5 @@
+import os
+
 import mock
 import pytest
 from sqlalchemy.pool import NullPool
@@ -216,3 +218,9 @@ def test_pool_class_nullpool(self, m_create_engine, app_nr):
         args, options = m_create_engine.call_args
         assert options['poolclass'].__name__ == 'NullPool'
         assert 'pool_size' not in options
+
+
+def test_sqlite_relative_to_app_root(app):
+    app.config["SQLALCHEMY_DATABASE_URI"] = "sqlite:///test.db"
+    db = fsa.SQLAlchemy(app)
+    assert db.engine.url.database == os.path.join(app.root_path, "test.db")