From c1f4db0a9b4a5e5cdb9d7bb2a52d7d2501d49a84 Mon Sep 17 00:00:00 2001
From: Adam Reichold <adam.reichold@t-online.de>
Date: Thu, 21 Dec 2023 09:55:54 +0100
Subject: [PATCH 1/2] Increase use of common get_or_try_init_type_ref helper
 when caching type objects.

---
 src/sync.rs           |  4 ++--
 src/types/mapping.rs  | 10 +++-------
 src/types/sequence.rs | 10 +++-------
 3 files changed, 8 insertions(+), 16 deletions(-)

diff --git a/src/sync.rs b/src/sync.rs
index 91a83106..62843113 100644
--- a/src/sync.rs
+++ b/src/sync.rs
@@ -1,5 +1,5 @@
 //! Synchronization mechanisms based on the Python GIL.
-use crate::{types::PyString, types::PyType, Py, PyErr, PyVisit, Python};
+use crate::{types::PyString, types::PyType, Py, PyResult, PyVisit, Python};
 use std::cell::UnsafeCell;
 
 /// Value with concurrent access protected by the GIL.
@@ -196,7 +196,7 @@ impl GILOnceCell<Py<PyType>> {
         py: Python<'py>,
         module_name: &str,
         attr_name: &str,
-    ) -> Result<&'py PyType, PyErr> {
+    ) -> PyResult<&'py PyType> {
         self.get_or_try_init(py, || py.import(module_name)?.getattr(attr_name)?.extract())
             .map(|ty| ty.as_ref(py))
     }
diff --git a/src/types/mapping.rs b/src/types/mapping.rs
index bf6a6d49..583fc468 100644
--- a/src/types/mapping.rs
+++ b/src/types/mapping.rs
@@ -240,14 +240,10 @@ impl<'py> PyMappingMethods<'py> for Py2<'py, PyMapping> {
     }
 }
 
-static MAPPING_ABC: GILOnceCell<Py<PyType>> = GILOnceCell::new();
-
 fn get_mapping_abc(py: Python<'_>) -> PyResult<&PyType> {
-    MAPPING_ABC
-        .get_or_try_init(py, || {
-            py.import("collections.abc")?.getattr("Mapping")?.extract()
-        })
-        .map(|ty| ty.as_ref(py))
+    static MAPPING_ABC: GILOnceCell<Py<PyType>> = GILOnceCell::new();
+
+    MAPPING_ABC.get_or_try_init_type_ref(py, "collections.abc", "Mapping")
 }
 
 impl PyTypeCheck for PyMapping {
diff --git a/src/types/sequence.rs b/src/types/sequence.rs
index c4c2b21b..beded132 100644
--- a/src/types/sequence.rs
+++ b/src/types/sequence.rs
@@ -523,14 +523,10 @@ where
     Ok(v)
 }
 
-static SEQUENCE_ABC: GILOnceCell<Py<PyType>> = GILOnceCell::new();
-
 fn get_sequence_abc(py: Python<'_>) -> PyResult<&PyType> {
-    SEQUENCE_ABC
-        .get_or_try_init(py, || {
-            py.import("collections.abc")?.getattr("Sequence")?.extract()
-        })
-        .map(|ty| ty.as_ref(py))
+    static SEQUENCE_ABC: GILOnceCell<Py<PyType>> = GILOnceCell::new();
+
+    SEQUENCE_ABC.get_or_try_init_type_ref(py, "collections.abc", "Sequence")
 }
 
 impl PyTypeCheck for PySequence {

From 3c97167fd139701d300e8935cc689edc91bdb41d Mon Sep 17 00:00:00 2001
From: Adam Reichold <adam.reichold@t-online.de>
Date: Thu, 21 Dec 2023 09:59:24 +0100
Subject: [PATCH 2/2] Use write_unraisable to report errors loading type
 objects for ABC checks.

---
 src/types/mapping.rs  | 6 ++++--
 src/types/sequence.rs | 6 ++++--
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/types/mapping.rs b/src/types/mapping.rs
index 583fc468..3199c548 100644
--- a/src/types/mapping.rs
+++ b/src/types/mapping.rs
@@ -256,8 +256,10 @@ impl PyTypeCheck for PyMapping {
         PyDict::is_type_of(object)
             || get_mapping_abc(object.py())
                 .and_then(|abc| object.is_instance(abc))
-                // TODO: surface errors in this chain to the user
-                .unwrap_or(false)
+                .unwrap_or_else(|err| {
+                    err.write_unraisable(object.py(), Some(object));
+                    false
+                })
     }
 }
 
diff --git a/src/types/sequence.rs b/src/types/sequence.rs
index beded132..cb1599d6 100644
--- a/src/types/sequence.rs
+++ b/src/types/sequence.rs
@@ -540,8 +540,10 @@ impl PyTypeCheck for PySequence {
             || PyTuple::is_type_of(object)
             || get_sequence_abc(object.py())
                 .and_then(|abc| object.is_instance(abc))
-                // TODO: surface errors in this chain to the user
-                .unwrap_or(false)
+                .unwrap_or_else(|err| {
+                    err.write_unraisable(object.py(), Some(object));
+                    false
+                })
     }
 }