From 2e6af653f6fa05c0706412fa6ac518a94081eb20 Mon Sep 17 00:00:00 2001
From: Thomas Waldmann <tw@waldmann-edv.de>
Date: Wed, 18 Feb 2026 22:40:22 +0100
Subject: [PATCH] hashindex: fixed iteritems segfaulting with non-existent
 marker, fixes #9368

Never happened in borg, because borg always gives existing markers to iteritems.

Also: added test for this.
---
 src/borg/hashindex.pyx                 |  8 +++----
 src/borg/testsuite/hashindex_pytest.py | 30 ++++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 4 deletions(-)
 create mode 100644 src/borg/testsuite/hashindex_pytest.py

diff --git a/src/borg/hashindex.pyx b/src/borg/hashindex.pyx
index 916df65ed..44f1fcbe1 100644
--- a/src/borg/hashindex.pyx
+++ b/src/borg/hashindex.pyx
@@ -237,8 +237,8 @@ cdef class NSIndex(IndexBase):
         iter.index = self.index
         if marker:
             key = hashindex_get(self.index, <unsigned char *>marker)
-            if marker is None:
-                raise IndexError
+            if not key:
+                raise KeyError("marker not found")
             iter.key = key - self.key_size
         return iter
 
@@ -354,8 +354,8 @@ cdef class ChunkIndex(IndexBase):
         iter.index = self.index
         if marker:
             key = hashindex_get(self.index, <unsigned char *>marker)
-            if marker is None:
-                raise IndexError
+            if not key:
+                raise KeyError("marker not found")
             iter.key = key - self.key_size
         return iter
 
diff --git a/src/borg/testsuite/hashindex_pytest.py b/src/borg/testsuite/hashindex_pytest.py
new file mode 100644
index 000000000..4a82775c7
--- /dev/null
+++ b/src/borg/testsuite/hashindex_pytest.py
@@ -0,0 +1,30 @@
+import pytest
+from borg.hashindex import NSIndex, ChunkIndex
+
+def test_nsindex_iteritems_marker():
+    nsindex = NSIndex()
+    nsindex[b'\xbb'*32] = (123, 456)
+    nsindex[b'\xaa'*32] = (234, 567)
+
+    # marker exists
+    items = list(nsindex.iteritems(marker=b'\xbb'*32))
+    assert len(items) == 1
+    assert items[0][0] == b'\xaa'*32
+
+    # marker does not exist
+    with pytest.raises(KeyError, match="marker not found"):
+        list(nsindex.iteritems(marker=b'\xcc'*32))
+
+def test_chunkindex_iteritems_marker():
+    chunkindex = ChunkIndex()
+    chunkindex[b'\xbb'*32] = (1, 100, 50)
+    chunkindex[b'\xaa'*32] = (1, 200, 100)
+
+    # marker exists
+    items = list(chunkindex.iteritems(marker=b'\xbb'*32))
+    assert len(items) == 1
+    assert items[0][0] == b'\xaa'*32
+
+    # marker does not exist
+    with pytest.raises(KeyError, match="marker not found"):
+        list(chunkindex.iteritems(marker=b'\xcc'*32))