From 2d216a07195d24cc9cce246f395ae5283ffbfb05 Mon Sep 17 00:00:00 2001
From: Marius Gedminas <marius@gedmin.as>
Date: Wed, 15 Jan 2025 12:29:44 +0200
Subject: [PATCH] Fix logic error in get_leaking_objects(objects)

Fixes #82, hopefully.

I see that I don't have any unit tests for this function, nor do I have
any idea how to test it without writing a custom C extension module with
intentional refcount bugs.
---
 CHANGES.rst |  5 ++++-
 objgraph.py | 20 ++++++++++++++++----
 2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/CHANGES.rst b/CHANGES.rst
index c9ad13d..c2188c2 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -6,7 +6,10 @@ Changes
 3.6.3 (unreleased)
 ------------------
 
-- Nothing changed yet.
+- Fix :func:`get_leaking_objects` with an ``objects`` argument to not ignore
+  references from other sources.  Closes `issue 82
+  <https://github.com/mgedmin/objgraph/issues/82>`_.
+  Also fix ``get_leaking_objects([])`` causing an UnboudLocalError.
 
 
 3.6.2 (2024-10-10)
diff --git a/objgraph.py b/objgraph.py
index d8d5ae9..2af915a 100755
--- a/objgraph.py
+++ b/objgraph.py
@@ -474,17 +474,29 @@ def get_leaking_objects(objects=None):
     These could indicate reference-counting bugs in C code.  Or they could
     be legitimate.
 
+    If you pass in a list of ``objects``, this function will return
+    a subset of them that have no referents, otherwise it will look among
+    all the objects tracked by the garbage collector.
+
     Note that the GC does not track simple objects like int or str.
 
+    Example:
+
+       >>> get_leaking_objects(by_type('MyClass'))
+       ...
+
     .. versionadded:: 1.7
     """
+    i = None  # prevent UnboundLocalError in finally: when objects is []
+    gc.collect()
+    all_objects = gc.get_objects()
     if objects is None:
-        gc.collect()
-        objects = gc.get_objects()
+        objects = all_objects
     try:
         ids = set(id(i) for i in objects)
-        for i in objects:
-            ids.difference_update(id(j) for j in gc.get_referents(i))
+        for i in all_objects:
+            if i is not objects:
+                ids.difference_update(id(j) for j in gc.get_referents(i))
         # this then is our set of objects without referrers
         return [i for i in objects if id(i) in ids]
     finally: