From a7e8cfbae8e53d2c4b1fb75d57d42f00db8abd81 Mon Sep 17 00:00:00 2001
From: "John L. Villalovos" <john@sodarock.com>
Date: Wed, 20 Jul 2022 08:34:08 -0700
Subject: [PATCH] chore: add a `lazy` boolean attribute to `RESTObject`

This can be used to tell if a `RESTObject` was created using
`lazy=True`.

Add a message to the `AttributeError` if attribute access fails for an
instance created with `lazy=True`.
---
 gitlab/base.py                          |  9 ++++++
 gitlab/mixins.py                        |  4 +--
 tests/unit/mixins/test_mixin_methods.py | 43 +++++++++++++++++++++++++
 3 files changed, 54 insertions(+), 2 deletions(-)

diff --git a/gitlab/base.py b/gitlab/base.py
index 920617b33..dd5924063 100644
--- a/gitlab/base.py
+++ b/gitlab/base.py
@@ -62,6 +62,7 @@ class RESTObject:
     _parent_attrs: Dict[str, Any]
     _repr_attr: Optional[str] = None
     _updated_attrs: Dict[str, Any]
+    _lazy: bool
     manager: "RESTManager"
 
     def __init__(
@@ -70,6 +71,7 @@ def __init__(
         attrs: Dict[str, Any],
         *,
         created_from_list: bool = False,
+        lazy: bool = False,
     ) -> None:
         if not isinstance(attrs, dict):
             raise GitlabParsingError(
@@ -84,6 +86,7 @@ def __init__(
                 "_updated_attrs": {},
                 "_module": importlib.import_module(self.__module__),
                 "_created_from_list": created_from_list,
+                "_lazy": lazy,
             }
         )
         self.__dict__["_parent_attrs"] = self.manager.parent_attrs
@@ -137,6 +140,12 @@ def __getattr__(self, name: str) -> Any:
                 )
                 + f"\n\n{_URL_ATTRIBUTE_ERROR}"
             )
+        elif self._lazy:
+            message = f"{message}\n\n" + textwrap.fill(
+                f"If you tried to access object attributes returned from the server, "
+                f"note that {self.__class__!r} was created as a `lazy` object and was "
+                f"not initialized with any data."
+            )
         raise AttributeError(message)
 
     def __setattr__(self, name: str, value: Any) -> None:
diff --git a/gitlab/mixins.py b/gitlab/mixins.py
index 519e83f1e..f33a1fcf7 100644
--- a/gitlab/mixins.py
+++ b/gitlab/mixins.py
@@ -135,11 +135,11 @@ def get(
         if lazy is True:
             if TYPE_CHECKING:
                 assert self._obj_cls._id_attr is not None
-            return self._obj_cls(self, {self._obj_cls._id_attr: id})
+            return self._obj_cls(self, {self._obj_cls._id_attr: id}, lazy=lazy)
         server_data = self.gitlab.http_get(path, **kwargs)
         if TYPE_CHECKING:
             assert not isinstance(server_data, requests.Response)
-        return self._obj_cls(self, server_data)
+        return self._obj_cls(self, server_data, lazy=lazy)
 
 
 class GetWithoutIdMixin(HeadMixin, _RestManagerBase):
diff --git a/tests/unit/mixins/test_mixin_methods.py b/tests/unit/mixins/test_mixin_methods.py
index c40ccbd81..9121453c4 100644
--- a/tests/unit/mixins/test_mixin_methods.py
+++ b/tests/unit/mixins/test_mixin_methods.py
@@ -45,9 +45,52 @@ class M(GetMixin, FakeManager):
     assert isinstance(obj, FakeObject)
     assert obj.foo == "bar"
     assert obj.id == 42
+    assert obj._lazy is False
     assert responses.assert_call_count(url, 1) is True
 
 
+def test_get_mixin_lazy(gl):
+    class M(GetMixin, FakeManager):
+        pass
+
+    url = "http://localhost/api/v4/tests/42"
+
+    mgr = M(gl)
+    with responses.RequestsMock(assert_all_requests_are_fired=False) as rsps:
+        rsps.add(
+            method=responses.GET,
+            url=url,
+            json={"id": 42, "foo": "bar"},
+            status=200,
+            match=[responses.matchers.query_param_matcher({})],
+        )
+        obj = mgr.get(42, lazy=True)
+    assert isinstance(obj, FakeObject)
+    assert not hasattr(obj, "foo")
+    assert obj.id == 42
+    assert obj._lazy is True
+    # a `lazy` get does not make a network request
+    assert not rsps.calls
+
+
+def test_get_mixin_lazy_missing_attribute(gl):
+    class FakeGetManager(GetMixin, FakeManager):
+        pass
+
+    manager = FakeGetManager(gl)
+    obj = manager.get(1, lazy=True)
+    assert obj.id == 1
+    with pytest.raises(AttributeError) as exc:
+        obj.missing_attribute
+    # undo `textwrap.fill()`
+    message = str(exc.value).replace("\n", " ")
+    assert "'FakeObject' object has no attribute 'missing_attribute'" in message
+    assert (
+        "note that <class 'tests.unit.mixins.test_mixin_methods.FakeObject'> was "
+        "created as a `lazy` object and was not initialized with any data."
+    ) in message
+
+
 @responses.activate
 def test_head_mixin(gl):
     class M(GetMixin, FakeManager):