From 17f31d6ce2df6df2db633fe67283744861b025f7 Mon Sep 17 00:00:00 2001
From: Shantanu <12621235+hauntsaninja@users.noreply.github.com>
Date: Thu, 21 Dec 2023 13:24:10 -0800
Subject: [PATCH] gh-95754: Better AttributeError on partially initialised
 module (#112577)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
---
 Lib/test/test_import/__init__.py              |  8 +++++++
 .../data/circular_imports/import_cycle.py     |  3 +++
 ...3-12-01-08-16-10.gh-issue-95754.ae4gwy.rst |  1 +
 Objects/moduleobject.c                        | 24 +++++++++++++++++--
 4 files changed, 34 insertions(+), 2 deletions(-)
 create mode 100644 Lib/test/test_import/data/circular_imports/import_cycle.py
 create mode 100644 Misc/NEWS.d/next/Core and Builtins/2023-12-01-08-16-10.gh-issue-95754.ae4gwy.rst

diff --git a/Lib/test/test_import/__init__.py b/Lib/test/test_import/__init__.py
index 48c0a43f29e27f8..7b0126226c4aba2 100644
--- a/Lib/test/test_import/__init__.py
+++ b/Lib/test/test_import/__init__.py
@@ -1632,6 +1632,14 @@ def test_circular_from_import(self):
             str(cm.exception),
         )
 
+    def test_circular_import(self):
+        with self.assertRaisesRegex(
+            AttributeError,
+            r"partially initialized module 'test.test_import.data.circular_imports.import_cycle' "
+            r"from '.*' has no attribute 'some_attribute' \(most likely due to a circular import\)"
+        ):
+            import test.test_import.data.circular_imports.import_cycle
+
     def test_absolute_circular_submodule(self):
         with self.assertRaises(AttributeError) as cm:
             import test.test_import.data.circular_imports.subpkg2.parent
diff --git a/Lib/test/test_import/data/circular_imports/import_cycle.py b/Lib/test/test_import/data/circular_imports/import_cycle.py
new file mode 100644
index 000000000000000..cd9507b5f69e254
--- /dev/null
+++ b/Lib/test/test_import/data/circular_imports/import_cycle.py
@@ -0,0 +1,3 @@
+import test.test_import.data.circular_imports.import_cycle as m
+
+m.some_attribute
diff --git a/Misc/NEWS.d/next/Core and Builtins/2023-12-01-08-16-10.gh-issue-95754.ae4gwy.rst b/Misc/NEWS.d/next/Core and Builtins/2023-12-01-08-16-10.gh-issue-95754.ae4gwy.rst
new file mode 100644
index 000000000000000..0884bc4a4be7269
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2023-12-01-08-16-10.gh-issue-95754.ae4gwy.rst	
@@ -0,0 +1 @@
+Provide a better error message when accessing invalid attributes on partially initialized modules. The origin of the module being accessed is now included in the message to help with the common issue of shadowing other modules.
diff --git a/Objects/moduleobject.c b/Objects/moduleobject.c
index e2741fef6debd3e..3a1c516658dce78 100644
--- a/Objects/moduleobject.c
+++ b/Objects/moduleobject.c
@@ -788,7 +788,7 @@ PyObject*
 _Py_module_getattro_impl(PyModuleObject *m, PyObject *name, int suppress)
 {
     // When suppress=1, this function suppresses AttributeError.
-    PyObject *attr, *mod_name, *getattr;
+    PyObject *attr, *mod_name, *getattr, *origin;
     attr = _PyObject_GenericGetAttrWithDict((PyObject *)m, name, NULL, suppress);
     if (attr) {
         return attr;
@@ -831,11 +831,31 @@ _Py_module_getattro_impl(PyModuleObject *m, PyObject *name, int suppress)
         if (suppress != 1) {
             int rc = _PyModuleSpec_IsInitializing(spec);
             if (rc > 0) {
-                PyErr_Format(PyExc_AttributeError,
+                int valid_spec = PyObject_GetOptionalAttr(spec, &_Py_ID(origin), &origin);
+                if (valid_spec == -1) {
+                    Py_XDECREF(spec);
+                    Py_DECREF(mod_name);
+                    return NULL;
+                }
+                if (valid_spec == 1 && !PyUnicode_Check(origin)) {
+                    valid_spec = 0;
+                    Py_DECREF(origin);
+                }
+                if (valid_spec == 1) {
+                    PyErr_Format(PyExc_AttributeError,
+                                "partially initialized "
+                                "module '%U' from '%U' has no attribute '%U' "
+                                "(most likely due to a circular import)",
+                                mod_name, origin, name);
+                    Py_DECREF(origin);
+                }
+                else {
+                    PyErr_Format(PyExc_AttributeError,
                                 "partially initialized "
                                 "module '%U' has no attribute '%U' "
                                 "(most likely due to a circular import)",
                                 mod_name, name);
+                }
             }
             else if (rc == 0) {
                 rc = _PyModuleSpec_IsUninitializedSubmodule(spec, name);