Merge "Support lambda expression in mypy plugin" into main

3 files changed, 23 insertions, 0 deletions

diff --git a/doc/build/changelog/unreleased_14/8196.rst b/doc/build/changelog/unreleased_14/8196.rst
new file mode 100644
index 000000000..d5afbb8f7
--- /dev/null
+++ b/doc/build/changelog/unreleased_14/8196.rst
@@ -0,0 +1,7 @@
+.. change::
+    :tags: bug, mypy
+    :tickets: 8196
+
+    Fixed a crash of the mypy plugin when using a lambda as a Column
+    default. Pull request curtesy of tchapi.
+
diff --git a/lib/sqlalchemy/ext/mypy/infer.py b/lib/sqlalchemy/ext/mypy/infer.py
index 08035d74c..479be40c3 100644
--- a/lib/sqlalchemy/ext/mypy/infer.py
+++ b/lib/sqlalchemy/ext/mypy/infer.py
@@ -16,6 +16,7 @@ from mypy.nodes import AssignmentStmt
 from mypy.nodes import CallExpr
 from mypy.nodes import Expression
 from mypy.nodes import FuncDef
+from mypy.nodes import LambdaExpr
 from mypy.nodes import MemberExpr
 from mypy.nodes import NameExpr
 from mypy.nodes import RefExpr
@@ -423,6 +424,10 @@ def _infer_type_from_decl_column(
         elif isinstance(column_arg, (StrExpr,)):
             # x = Column("name", String), go to next argument
             continue
+        elif isinstance(column_arg, (LambdaExpr,)):
+            # x = Column("name", String, default=lambda: uuid.uuid4())
+            # go to next argument
+            continue
         else:
             assert False
 
diff --git a/test/ext/mypy/plugin_files/lambda_default.py b/test/ext/mypy/plugin_files/lambda_default.py
new file mode 100644
index 000000000..a1019f0d0
--- /dev/null
+++ b/test/ext/mypy/plugin_files/lambda_default.py
@@ -0,0 +1,11 @@
+import uuid
+
+from sqlalchemy import Column
+from sqlalchemy import String
+from sqlalchemy.orm import declarative_base
+
+Base = declarative_base()
+
+
+class MyClass(Base):
+    id = Column(String, default=lambda: uuid.uuid4(), primary_key=True)