From c8641f879f3dac0ce92338a6b87b687b7efe25d7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ville=20Skytt=C3=A4?= <ville.skytta@iki.fi>
Date: Thu, 18 May 2023 16:11:47 +0300
Subject: [PATCH] Include reason in cache path warnings to aid debugging
 (#11005)

Co-authored-by: Bruno Oliveira <nicoddemus@gmail.com>
---
 changelog/11005.improvement.rst |  1 +
 src/_pytest/cacheprovider.py    | 14 ++++++++++----
 testing/test_cacheprovider.py   |  2 +-
 3 files changed, 12 insertions(+), 5 deletions(-)
 create mode 100644 changelog/11005.improvement.rst

diff --git a/changelog/11005.improvement.rst b/changelog/11005.improvement.rst
new file mode 100644
index 000000000..295252514
--- /dev/null
+++ b/changelog/11005.improvement.rst
@@ -0,0 +1 @@
+Added underlying exception to cache provider path creation and write warning messages.
diff --git a/src/_pytest/cacheprovider.py b/src/_pytest/cacheprovider.py
index 719b32f7e..89a4a55f8 100755
--- a/src/_pytest/cacheprovider.py
+++ b/src/_pytest/cacheprovider.py
@@ -179,16 +179,22 @@ class Cache:
             else:
                 cache_dir_exists_already = self._cachedir.exists()
                 path.parent.mkdir(exist_ok=True, parents=True)
-        except OSError:
-            self.warn("could not create cache path {path}", path=path, _ispytest=True)
+        except OSError as exc:
+            self.warn(
+                f"could not create cache path {path}: {exc}",
+                _ispytest=True,
+            )
             return
         if not cache_dir_exists_already:
             self._ensure_supporting_files()
         data = json.dumps(value, ensure_ascii=False, indent=2)
         try:
             f = path.open("w", encoding="UTF-8")
-        except OSError:
-            self.warn("cache could not write path {path}", path=path, _ispytest=True)
+        except OSError as exc:
+            self.warn(
+                f"cache could not write path {path}: {exc}",
+                _ispytest=True,
+            )
         else:
             with f:
                 f.write(data)
diff --git a/testing/test_cacheprovider.py b/testing/test_cacheprovider.py
index 2f8517f99..ee2fe1845 100644
--- a/testing/test_cacheprovider.py
+++ b/testing/test_cacheprovider.py
@@ -87,7 +87,7 @@ class TestNewAPI:
                 "*= warnings summary =*",
                 "*/cacheprovider.py:*",
                 "  */cacheprovider.py:*: PytestCacheWarning: could not create cache path "
-                f"{unwritable_cache_dir}/v/cache/nodeids",
+                f"{unwritable_cache_dir}/v/cache/nodeids: *",
                 '    config.cache.set("cache/nodeids", sorted(self.cached_nodeids))',
                 "*1 failed, 3 warnings in*",
             ]