From 1687f5d5a891758f59dcbc4f4f0b57351aac7988 Mon Sep 17 00:00:00 2001
From: John Litborn <11260241+jakkdl@users.noreply.github.com>
Date: Tue, 11 Jul 2023 23:48:48 +0200
Subject: [PATCH] fix PermissionError due to accessing pthreads upon importing
 trio (#2693)

* fix PermissionError due to accessing pthreads upon importing trio

* fix codecov

* add newsfragment
---
 newsfragments/2688.bugfix.rst | 1 +
 trio/_core/_thread_cache.py   | 9 ++++++++-
 2 files changed, 9 insertions(+), 1 deletion(-)
 create mode 100644 newsfragments/2688.bugfix.rst

diff --git a/newsfragments/2688.bugfix.rst b/newsfragments/2688.bugfix.rst
new file mode 100644
index 0000000000..95f16feff7
--- /dev/null
+++ b/newsfragments/2688.bugfix.rst
@@ -0,0 +1 @@
+Fix ``PermissionError`` when importing `trio` due to trying to access ``pthread``.
diff --git a/trio/_core/_thread_cache.py b/trio/_core/_thread_cache.py
index e570e8dead..cc272fc92c 100644
--- a/trio/_core/_thread_cache.py
+++ b/trio/_core/_thread_cache.py
@@ -39,7 +39,14 @@ def darwin_namefunc(
     libpthread_path = ctypes.util.find_library("pthread")
     if not libpthread_path:
         return None
-    libpthread = ctypes.CDLL(libpthread_path)
+
+    # Sometimes windows can find the path, but gives a permission error when
+    # accessing it. Catching a wider exception in case of more esoteric errors.
+    # https://github.com/python-trio/trio/issues/2688
+    try:
+        libpthread = ctypes.CDLL(libpthread_path)
+    except Exception:  # pragma: no cover
+        return None
 
     # get the setname method from it
     # afaik this should never fail