Fix: we can't inspect built-in routines to get their file (#2720)

Author: georgesittas

sqlmesh/utils/metaprogramming.py

@@ -347,15 +347,18 @@ def serialize_env(env: t.Dict[str, t.Any], path: Path) -> t.Dict[str, Executable
         if callable(v):
             name = v.__name__
             name = k if name == "<lambda>" else name
-            file_path = Path(inspect.getfile(v))
+
+            # We can't call getfile on built-in callables
+            # https://docs.python.org/3/library/inspect.html#inspect.getfile
+            file_path = Path(inspect.getfile(v)) if not inspect.isbuiltin(v) else None
 
             if _is_relative_to(file_path, path):
                 serialized[k] = Executable(
                     name=name,
                     payload=normalize_source(v),
                     kind=ExecutableKind.DEFINITION,
                     # Do `as_posix` to serialize windows path back to POSIX
-                    path=file_path.relative_to(path.absolute()).as_posix(),
+                    path=t.cast(Path, file_path).relative_to(path.absolute()).as_posix(),
                     alias=k if name != k else None,
                 )
             else:

tests/core/test_model.py

@@ -1517,11 +1517,16 @@ def test_parse(assert_exp_eq):
 
 
 def test_python_model(assert_exp_eq) -> None:
+    from functools import reduce
+
     @model(name="my_model", kind="full", columns={'"COL"': "int"})
     def my_model(context, **kwargs):
         context.table("foo")
         context.table(model_name=CONST + ".baz")
 
+        # This checks that built-in functions are serialized properly
+        a = reduce(lambda x, y: x + y, [1, 2, 3, 4])  # noqa: F841
+
     m = model.get_registry()["my_model"].model(
         module_path=Path("."),
         path=Path("."),