workaround for https://github.com/kvesteri/sqlalchemy-continuum/issues/264

ihatemoney/models.py

@@ -21,6 +21,7 @@ from sqlalchemy_continuum.plugins import FlaskPlugin
 from werkzeug.security import generate_password_hash
 
 from ihatemoney.currency_convertor import CurrencyConverter
+from ihatemoney.monkeypath_continuum import PatchedTransactionFactory
 from ihatemoney.utils import get_members, same_bill
 from ihatemoney.versioning import (
     ConditionalVersioningManager,
@@ -35,6 +36,8 @@ make_versioned(
         # Conditionally Disable the versioning based on each
         # project's privacy preferences
         tracking_predicate=version_privacy_predicate,
+        # MonkeyPatching
+        transaction_cls=PatchedTransactionFactory(),
     ),
     plugins=[
         FlaskPlugin(

ihatemoney/monkeypath_continuum.py

@@ -0,0 +1,97 @@
+from collections import OrderedDict
+
+import six
+import sqlalchemy as sa
+from sqlalchemy_continuum import __version__ as continuum_version
+from sqlalchemy_continuum.exc import ImproperlyConfigured
+from sqlalchemy_continuum.transaction import (
+    TransactionBase,
+    TransactionFactory,
+    create_triggers,
+)
+
+if continuum_version != "1.3.14":
+    import warnings
+
+    warnings.warn(
+        "SQLAlchemy-continuum version changed. Please check monkeypatching usefulness."
+    )
+
+
+class PatchedTransactionFactory(TransactionFactory):
+    """
+    Monkeypatching TransactionFactory for
+    https://github.com/kvesteri/sqlalchemy-continuum/issues/264
+    There is no easy way to really remove Sequence without redefining the whole method. So,
+    this is a copy/paste. :/
+    """
+
+    def create_class(self, manager):
+        """
+        Create Transaction class.
+        """
+
+        class Transaction(manager.declarative_base, TransactionBase):
+            __tablename__ = "transaction"
+            __versioning_manager__ = manager
+
+            id = sa.Column(
+                sa.types.BigInteger,
+                # sa.schema.Sequence('transaction_id_seq'),
+                primary_key=True,
+                autoincrement=True,
+            )
+
+            if self.remote_addr:
+                remote_addr = sa.Column(sa.String(50))
+
+            if manager.user_cls:
+                user_cls = manager.user_cls
+                Base = manager.declarative_base
+                try:
+                    registry = Base.registry._class_registry
+                except AttributeError:  # SQLAlchemy < 1.4
+                    registry = Base._decl_class_registry
+
+                if isinstance(user_cls, six.string_types):
+                    try:
+                        user_cls = registry[user_cls]
+                    except KeyError:
+                        raise ImproperlyConfigured(
+                            "Could not build relationship between Transaction"
+                            " and %s. %s was not found in declarative class "
+                            "registry. Either configure VersioningManager to "
+                            "use different user class or disable this "
+                            "relationship " % (user_cls, user_cls)
+                        )
+
+                user_id = sa.Column(
+                    sa.inspect(user_cls).primary_key[0].type,
+                    sa.ForeignKey(sa.inspect(user_cls).primary_key[0]),
+                    index=True,
+                )
+
+                user = sa.orm.relationship(user_cls)
+
+            def __repr__(self):
+                fields = ["id", "issued_at", "user"]
+                field_values = OrderedDict(
+                    (field, getattr(self, field))
+                    for field in fields
+                    if hasattr(self, field)
+                )
+                return "<Transaction %s>" % ", ".join(
+                    (
+                        "%s=%r" % (field, value)
+                        if not isinstance(value, six.integer_types)
+                        # We want the following line to ensure that longs get
+                        # shown without the ugly L suffix on python 2.x
+                        # versions
+                        else "%s=%d" % (field, value)
+                        for field, value in field_values.items()
+                    )
+                )
+
+        if manager.options["native_versioning"]:
+            create_triggers(Transaction)
+        return Transaction