feat: add recursion guard

docs/examples/library_factories/sqlalchemy_factory/test_example_4.py

@@ -0,0 +1,60 @@
+from typing import List
+
+from sqlalchemy import ForeignKey, create_engine
+from sqlalchemy.orm import DeclarativeBase, Mapped, Session, mapped_column, relationship
+
+from polyfactory.factories.sqlalchemy_factory import SQLAlchemyFactory, T
+
+
+class Base(DeclarativeBase):
+    ...
+
+
+class Author(Base):
+    __tablename__ = "authors"
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    name: Mapped[str]
+
+    books: Mapped[List["Book"]] = relationship(
+        "Book",
+        uselist=True,
+        back_populates="author",
+    )
+
+
+class Book(Base):
+    __tablename__ = "books"
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    author_id: Mapped[int] = mapped_column(ForeignKey(Author.id), nullable=False)
+    author: Mapped[Author] = relationship(
+        "Author",
+        uselist=False,
+        back_populates="books",
+    )
+
+
+class BaseFactory(SQLAlchemyFactory[T]):
+    __is_base_factory__ = True
+    __set_relationships__ = True
+    __randomize_collection_length__ = True
+    __min_collection_length__ = 3
+
+
+def test_custom_sqla_factory() -> None:
+    engine = create_engine("sqlite:///:memory:")
+    Base.metadata.create_all(engine)
+    session = Session(engine)
+
+    BaseFactory.__session__ = session  # Or using a callable that returns a session
+
+    author = BaseFactory.create_factory(Author).create_sync()
+    assert author.id is not None
+    assert author.id == author.books[0].author_id
+
+    book = BaseFactory.create_factory(Book).create_sync()
+    assert book.id is not None
+    assert book.author.books == [book]
+
+    BaseFactory._base_factories.remove(BaseFactory)  # noqa: SLF001

docs/usage/library_factories/sqlalchemy_factory.rst

@@ -37,6 +37,16 @@ By default, this will add generated models to the session and then commit. This
 Similarly for ``__async_session__`` and ``create_async``.
 
 
+Adding global overrides
+------------------------------
+
+By combining the above and using other settings, a global base factory can be set up for other factories.
+
+.. literalinclude:: /examples/library_factories/sqlalchemy_factory/test_example_4.py
+    :caption: Using persistence
+    :language: python
+
+
 API reference
 ------------------------------
 Full API docs are available :class:`here <polyfactory.factories.sqlalchemy_factory.SQLAlchemyFactory>`.