From 046f9fe39281d73781e24e43010908a912914c14 Mon Sep 17 00:00:00 2001
From: Thomas Waldmann <tw@waldmann-edv.de>
Date: Thu, 16 Nov 2023 14:40:06 +0100
Subject: [PATCH 1/2] LockRoster.modify: no KeyError if element was already
 gone, fixes #7937

The intention of LockRoster.modify(key, REMOVE) is to remove self.id.

Using set.discard will just ignore it if self.id is not present there anymore.

Previously, using set.remove triggered a KeyError that has been frequently
seen in tracebacks of teardowns involving Repository.__del__ and Repository.__exit__.

I added a REMOVE2 op to serve one caller that needs to get the KeyError if
self.id was not present.

Thanks to @herrmanntom for the workaround!
---
 src/borg/locking.py           | 9 +++++++--
 src/borg/testsuite/locking.py | 2 +-
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/borg/locking.py b/src/borg/locking.py
index ca64eeb06..59508180d 100644
--- a/src/borg/locking.py
+++ b/src/borg/locking.py
@@ -8,7 +8,7 @@ from . import platform
 from .helpers import Error, ErrorWithTraceback
 from .logger import create_logger
 
-ADD, REMOVE = "add", "remove"
+ADD, REMOVE, REMOVE2 = "add", "remove", "remove2"
 SHARED, EXCLUSIVE = "shared", "exclusive"
 
 logger = create_logger(__name__)
@@ -326,6 +326,11 @@ class LockRoster:
         if op == ADD:
             elements.add(self.id)
         elif op == REMOVE:
+            # note: we ignore it if the element is already not present anymore.
+            # this has been frequently seen in teardowns involving Repository.__del__ and Repository.__exit__.
+            elements.discard(self.id)
+        elif op == REMOVE2:
+            # needed for callers that do not want to ignore.
             elements.remove(self.id)
         else:
             raise ValueError("Unknown LockRoster op %r" % op)
@@ -340,7 +345,7 @@ class LockRoster:
         killing, self.kill_stale_locks = self.kill_stale_locks, False
         try:
             try:
-                self.modify(key, REMOVE)
+                self.modify(key, REMOVE2)
             except KeyError:
                 # entry was not there, so no need to add a new one, but still update our id
                 self.id = new_id
diff --git a/src/borg/testsuite/locking.py b/src/borg/testsuite/locking.py
index ea1bdb5f5..131fdef3a 100644
--- a/src/borg/testsuite/locking.py
+++ b/src/borg/testsuite/locking.py
@@ -280,7 +280,7 @@ class TestLock:
             assert roster.get(SHARED) == {our_id}
         assert roster.get(EXCLUSIVE) == set()
         assert roster.get(SHARED) == set()
-        with pytest.raises(KeyError):
+        with pytest.raises(NotLocked):
             dead_lock.release()
 
         with Lock(lockpath, id=cant_know_if_dead_id, exclusive=True):

From 2d86b7e1ac24c3413f885ee08b815d5553945ed9 Mon Sep 17 00:00:00 2001
From: Thomas Waldmann <tw@waldmann-edv.de>
Date: Sat, 18 Nov 2023 18:31:43 +0100
Subject: [PATCH 2/2] add type annotation for mypy

---
 src/borg/repository.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/borg/repository.py b/src/borg/repository.py
index bdc801b45..d16c461f1 100644
--- a/src/borg/repository.py
+++ b/src/borg/repository.py
@@ -11,6 +11,7 @@ from configparser import ConfigParser
 from datetime import datetime, timezone
 from functools import partial
 from itertools import islice
+from typing import Callable, DefaultDict
 
 from .constants import *  # NOQA
 from .hashindex import NSIndexEntry, NSIndex, NSIndex1, hashindex_variant
@@ -48,7 +49,7 @@ TAG_PUT2 = 3
 # may not be able to handle the new tags.
 MAX_TAG_ID = 15
 
-FreeSpace = partial(defaultdict, int)
+FreeSpace: Callable[[], DefaultDict] = partial(defaultdict, int)
 
 
 def header_size(tag):