From fabcbe9c12688eb9a902a5c89cb720ed373625c5 Mon Sep 17 00:00:00 2001
From: shailshouryya <42100758+shailshouryya@users.noreply.github.com>
Date: Tue, 25 Jul 2023 10:27:36 -0700
Subject: gh-106739: Add `rtype_cache` to `warnings.warn` message when leaked
 objects found (#106740)

Adding the `rtype_cache` to the `warnings.warn` message improves the
previous, somewhat vague message from

```
/Users/username/cpython/Lib/multiprocessing/resource_tracker.py:224: UserWarning: resource_tracker: There appear to be 6 leaked semaphore objects to clean up at shutdown
```

to

```
/Users/username/cpython/Lib/multiprocessing/resource_tracker.py:224: UserWarning: resource_tracker: There appear to be 6 leaked semaphore objects to clean up at shutdown: {'/mp-yor5cvj8', '/mp-10jx8eqr', '/mp-eobsx9tt', '/mp-0lml23vl', '/mp-9dgtsa_m', '/mp-frntyv4s'}
```

---------

Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com>
---
 Lib/multiprocessing/resource_tracker.py                            | 7 ++++---
 .../next/Library/2023-07-20-06-00-35.gh-issue-106739.W1hygr.rst    | 1 +
 2 files changed, 5 insertions(+), 3 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Library/2023-07-20-06-00-35.gh-issue-106739.W1hygr.rst

diff --git a/Lib/multiprocessing/resource_tracker.py b/Lib/multiprocessing/resource_tracker.py
index ea36950..3783c1f 100644
--- a/Lib/multiprocessing/resource_tracker.py
+++ b/Lib/multiprocessing/resource_tracker.py
@@ -221,9 +221,10 @@ def main(fd):
         for rtype, rtype_cache in cache.items():
             if rtype_cache:
                 try:
-                    warnings.warn('resource_tracker: There appear to be %d '
-                                  'leaked %s objects to clean up at shutdown' %
-                                  (len(rtype_cache), rtype))
+                    warnings.warn(
+                        f'resource_tracker: There appear to be {len(rtype_cache)} '
+                        f'leaked {rtype} objects to clean up at shutdown: {rtype_cache}'
+                    )
                 except Exception:
                     pass
             for name in rtype_cache:
diff --git a/Misc/NEWS.d/next/Library/2023-07-20-06-00-35.gh-issue-106739.W1hygr.rst b/Misc/NEWS.d/next/Library/2023-07-20-06-00-35.gh-issue-106739.W1hygr.rst
new file mode 100644
index 0000000..168e201
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2023-07-20-06-00-35.gh-issue-106739.W1hygr.rst
@@ -0,0 +1 @@
+Add the ``rtype_cache`` to the warning message (as an addition to the type of leaked objects and the number of leaked objects already included in the message) to make debugging leaked objects easier when the multiprocessing resource tracker process finds leaked objects at shutdown. This helps more quickly identify what was leaked and/or why the leaked object was not properly cleaned up.
-- 
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