From c777c0164e622651cdd2d9aaf92cdd59232e0433 Mon Sep 17 00:00:00 2001
From: SomberNight <somber.night@protonmail.com>
Date: Sat, 23 Aug 2025 15:04:05 +0000
Subject: [PATCH 1/2] util: move DebugMem from util to utils/memory_leak.py

---
 electrum/util.py              | 29 -------------------------
 electrum/utils/memory_leak.py | 41 +++++++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+), 29 deletions(-)
 create mode 100644 electrum/utils/memory_leak.py

diff --git a/electrum/util.py b/electrum/util.py
index 0bad5f510..93f75466f 100644
--- a/electrum/util.py
+++ b/electrum/util.py
@@ -350,35 +350,6 @@ class ThreadJob(Logger):
         """Called periodically from the thread"""
         pass
 
-class DebugMem(ThreadJob):
-    '''A handy class for debugging GC memory leaks'''
-    def __init__(self, classes, interval=30):
-        ThreadJob.__init__(self)
-        self.next_time = 0
-        self.classes = classes
-        self.interval = interval
-
-    def mem_stats(self):
-        import gc
-        self.logger.info("Start memscan")
-        gc.collect()
-        objmap = defaultdict(list)
-        for obj in gc.get_objects():
-            for class_ in self.classes:
-                try:
-                    _isinstance = isinstance(obj, class_)
-                except AttributeError:
-                    _isinstance = False
-                if _isinstance:
-                    objmap[class_].append(obj)
-        for class_, objs in objmap.items():
-            self.logger.info(f"{class_.__name__}: {len(objs)}")
-        self.logger.info("Finish memscan")
-
-    def run(self):
-        if time.time() > self.next_time:
-            self.mem_stats()
-            self.next_time = time.time() + self.interval
 
 class DaemonThread(threading.Thread, Logger):
     """ daemon thread that terminates cleanly """
diff --git a/electrum/utils/memory_leak.py b/electrum/utils/memory_leak.py
new file mode 100644
index 000000000..8b276d52c
--- /dev/null
+++ b/electrum/utils/memory_leak.py
@@ -0,0 +1,41 @@
+from collections import defaultdict
+import time
+
+from electrum.util import ThreadJob
+
+
+class DebugMem(ThreadJob):
+    '''A handy class for debugging GC memory leaks
+
+    In console:
+    >>> from electrum.utils.memory_leak import DebugMem
+    >>> from electrum.wallet import Abstract_Wallet
+    >>> plugins.add_jobs([DebugMem([Abstract_Wallet,], interval=5)])
+    '''
+    def __init__(self, classes, interval=30):
+        ThreadJob.__init__(self)
+        self.next_time = 0
+        self.classes = classes
+        self.interval = interval
+
+    def mem_stats(self):
+        import gc
+        self.logger.info("Start memscan")
+        gc.collect()
+        objmap = defaultdict(list)
+        for obj in gc.get_objects():
+            for class_ in self.classes:
+                try:
+                    _isinstance = isinstance(obj, class_)
+                except AttributeError:
+                    _isinstance = False
+                if _isinstance:
+                    objmap[class_].append(obj)
+        for class_, objs in objmap.items():
+            self.logger.info(f"{class_.__name__}: {len(objs)}")
+        self.logger.info("Finish memscan")
+
+    def run(self):
+        if time.time() > self.next_time:
+            self.mem_stats()
+            self.next_time = time.time() + self.interval

From 41269b9c88dd67a876d635525ebb8a59a52489de Mon Sep 17 00:00:00 2001
From: SomberNight <somber.night@protonmail.com>
Date: Sat, 23 Aug 2025 15:49:46 +0000
Subject: [PATCH 2/2] utils/memory_leak: add helpers using 3rd-party package
 "objgraph"

we will not start depending on "objgraph", to be clear
---
 electrum/utils/memory_leak.py | 38 ++++++++++++++++++++++++++++++++++-
 1 file changed, 37 insertions(+), 1 deletion(-)

diff --git a/electrum/utils/memory_leak.py b/electrum/utils/memory_leak.py
index 8b276d52c..0d3b463bd 100644
--- a/electrum/utils/memory_leak.py
+++ b/electrum/utils/memory_leak.py
@@ -1,4 +1,6 @@
 from collections import defaultdict
+import datetime
+import os
 import time
 
 from electrum.util import ThreadJob
@@ -7,7 +9,7 @@ from electrum.util import ThreadJob
 class DebugMem(ThreadJob):
     '''A handy class for debugging GC memory leaks
 
-    In console:
+    In Qt console:
     >>> from electrum.utils.memory_leak import DebugMem
     >>> from electrum.wallet import Abstract_Wallet
     >>> plugins.add_jobs([DebugMem([Abstract_Wallet,], interval=5)])
@@ -39,3 +41,37 @@ class DebugMem(ThreadJob):
         if time.time() > self.next_time:
             self.mem_stats()
             self.next_time = time.time() + self.interval
+
+
+def debug_memusage_list_all_objects(limit: int = 50) -> list[tuple[str, int]]:
+    """Return a string listing the most common types in memory."""
+    import objgraph  # 3rd-party dependency
+    return objgraph.most_common_types(
+        limit=limit,
+        shortnames=False,
+    )
+
+
+def debug_memusage_dump_random_backref_chain(objtype: str) -> str:
+    """Writes a dotfile to cwd, containing the backref chain
+    for a randomly selected object of type objtype.
+
+    Warning: very slow!
+
+    In Qt console:
+    >>> debug_memusage_dump_random_backref_chain("Standard_Wallet")
+
+    To convert to image:
+    $ dot -Tps filename.dot -o outfile.ps
+    """
+    import objgraph  # 3rd-party dependency
+    import random
+    timestamp = datetime.datetime.now(datetime.timezone.utc).strftime("%Y%m%dT%H%M%SZ")
+    fpath = os.path.abspath(f"electrum_backref_chain_{timestamp}.dot")
+    with open(fpath, "w") as f:
+        objgraph.show_chain(
+            objgraph.find_backref_chain(
+                random.choice(objgraph.by_type(objtype)),
+                objgraph.is_proper_module),
+            output=f)
+    return fpath