From 272997555e074376582a85f91c8975b103a1f6ee Mon Sep 17 00:00:00 2001
From: David Hewitt <1939362+davidhewitt@users.noreply.github.com>
Date: Tue, 11 Jul 2023 21:48:46 +0100
Subject: [PATCH] optimize is_instance for PyBaseException

---
 src/err/mod.rs    | 6 ++----
 src/exceptions.rs | 8 +++++---
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/err/mod.rs b/src/err/mod.rs
index 3af7b92b..0855a4b6 100644
--- a/src/err/mod.rs
+++ b/src/err/mod.rs
@@ -181,12 +181,10 @@ impl PyErr {
     /// });
     /// ```
     pub fn from_value(obj: &PyAny) -> PyErr {
-        let ptr = obj.as_ptr();
-
-        let state = if unsafe { ffi::PyExceptionInstance_Check(ptr) } != 0 {
+        let state = if let Ok(obj) = obj.downcast::<PyBaseException>() {
             PyErrState::Normalized(PyErrStateNormalized {
                 ptype: obj.get_type().into(),
-                pvalue: unsafe { Py::from_borrowed_ptr(obj.py(), obj.as_ptr()) },
+                pvalue: obj.into(),
                 ptraceback: None,
             })
         } else if unsafe { ffi::PyExceptionClass_Check(obj.as_ptr()) } != 0 {
diff --git a/src/exceptions.rs b/src/exceptions.rs
index a345274c..b1b5ba00 100644
--- a/src/exceptions.rs
+++ b/src/exceptions.rs
@@ -260,13 +260,13 @@ macro_rules! create_exception_type_object {
 }
 
 macro_rules! impl_native_exception (
-    ($name:ident, $exc_name:ident, $doc:expr, $layout:path) => (
+    ($name:ident, $exc_name:ident, $doc:expr, $layout:path $(, #checkfunction=$checkfunction:path)?) => (
         #[doc = $doc]
         #[allow(clippy::upper_case_acronyms)]
         pub struct $name($crate::PyAny);
 
         $crate::impl_exception_boilerplate!($name);
-        $crate::pyobject_native_type!($name, $layout, |_py| unsafe { $crate::ffi::$exc_name as *mut $crate::ffi::PyTypeObject });
+        $crate::pyobject_native_type!($name, $layout, |_py| unsafe { $crate::ffi::$exc_name as *mut $crate::ffi::PyTypeObject } $(, #checkfunction=$checkfunction)?);
     );
     ($name:ident, $exc_name:ident, $doc:expr) => (
         impl_native_exception!($name, $exc_name, $doc, $crate::ffi::PyBaseExceptionObject);
@@ -359,7 +359,9 @@ Python::with_gil(|py| {
 impl_native_exception!(
     PyBaseException,
     PyExc_BaseException,
-    native_doc!("BaseException")
+    native_doc!("BaseException"),
+    ffi::PyBaseExceptionObject,
+    #checkfunction=ffi::PyExceptionInstance_Check
 );
 impl_native_exception!(PyException, PyExc_Exception, native_doc!("Exception"));
 impl_native_exception!(