Merge pull request #9203 from ThomasWaldmann/fix-compact-1.4

compact: fix dealing with mismatching hints (1.4-maint)

src/borg/repository.py

@@ -796,7 +796,8 @@ class Repository:
             for segment in unused:
                 logger.debug('complete_xfer: deleting unused segment %d', segment)
                 count = self.segments.pop(segment)
-                assert count == 0, 'Corrupted segment reference count - corrupted index or hints'
+                if count != 0:
+                    logger.warning('Corrupted segment reference count %d (expected 0) for segment %d - corrupted index or hints', count, segment)
                 self.io.delete_segment(segment)
                 del self.compact[segment]
             unused = []
@@ -807,7 +808,8 @@ class Repository:
         for segment, freeable_space in sorted(self.compact.items()):
             if not self.io.segment_exists(segment):
                 logger.warning('segment %d not found, but listed in compaction data', segment)
-                del self.compact[segment]
+                self.compact.pop(segment, None)
+                self.segments.pop(segment, None)
                 pi.show()
                 continue
             segment_size = self.io.segment_size(segment)
@@ -907,7 +909,8 @@ class Repository:
                         if not self.shadow_index[key]:
                             # shadowed segments list is empty -> remove it
                             del self.shadow_index[key]
-            assert segments[segment] == 0, 'Corrupted segment reference count - corrupted index or hints'
+            if segments[segment] != 0:
+                logger.warning('Corrupted segment reference count %d (expected 0) for segment %d - corrupted index or hints', segments[segment], segment)
             unused.append(segment)
             pi.show()
         pi.finish()

src/borg/testsuite/issue_8535.py

@@ -0,0 +1,109 @@
+import os
+import pytest
+from borg.constants import *  # noqa: F403
+from borg.helpers import msgpack
+from borg.testsuite.archiver import exec_cmd
+
+
+@pytest.fixture
+def borg_env(tmp_path, monkeypatch):
+    monkeypatch.setenv('BORG_CHECK_I_KNOW_WHAT_I_AM_DOING', 'YES')
+    monkeypatch.setenv('BORG_DELETE_I_KNOW_WHAT_I_AM_DOING', 'YES')
+    monkeypatch.setenv('BORG_PASSPHRASE', 'waytooeasyonlyfortests')
+    monkeypatch.setenv('BORG_SELFTEST', 'disabled')
+
+    # Set up directories
+    keys_path = tmp_path / 'keys'
+    cache_path = tmp_path / 'cache'
+    input_path = tmp_path / 'input'
+
+    monkeypatch.setenv('BORG_KEYS_DIR', str(keys_path))
+    monkeypatch.setenv('BORG_CACHE_DIR', str(cache_path))
+
+    keys_path.mkdir()
+    cache_path.mkdir()
+    input_path.mkdir()
+
+    # Create test file
+    (input_path / 'file1').write_bytes(b'X' * 1024 * 80)
+
+    cwd = os.getcwd()
+    os.chdir(tmp_path)
+    yield {
+        'repo': str(tmp_path / 'repository'),
+        'input': str(input_path),
+    }
+    os.chdir(cwd)
+
+
+def cmd(*args, **kw):
+    kw.setdefault('fork', True)
+    ret, output = exec_cmd(*args, **kw)
+    if ret != 0:
+        print(output)
+    assert ret == 0
+    return output
+
+
+def test_missing_segment_in_hints(borg_env):
+    """Test that compact handles missing segment files gracefully."""
+    repo = borg_env['repo']
+
+    cmd('init', '--encryption=none', repo)
+    cmd('create', repo + '::archive1', 'input')
+    cmd('delete', repo + '::archive1')
+
+    # Find hints
+    hints_files = sorted([f for f in os.listdir(repo) if f.startswith('hints.') and not f.endswith('.tmp')],
+                         key=lambda x: int(x.split('.')[1]))
+    hints_file = os.path.join(repo, hints_files[-1])
+
+    with open(hints_file, 'rb') as f:
+        hints = msgpack.unpack(f)
+
+    # Find data segment
+    target_segment = None
+    for seg in hints[b'compact'].keys():
+        segment_file = os.path.join(repo, 'data', str(seg // 10000), str(seg))
+        if os.path.exists(segment_file) and os.path.getsize(segment_file) > 100:
+            target_segment = seg
+            break
+
+    assert target_segment is not None
+
+    # Delete segment file
+    segment_file = os.path.join(repo, 'data', str(target_segment // 10000), str(target_segment))
+    os.unlink(segment_file)
+
+    # Compact should succeed
+    cmd('compact', repo)
+
+    # Verify hints updated
+    hints_files = sorted([f for f in os.listdir(repo) if f.startswith('hints.') and not f.endswith('.tmp')],
+                         key=lambda x: int(x.split('.')[1]))
+    new_hints_file = os.path.join(repo, hints_files[-1])
+
+    with open(new_hints_file, 'rb') as f:
+        new_hints = msgpack.unpack(f)
+
+    assert target_segment not in new_hints[b'compact']
+    assert target_segment not in new_hints[b'segments']
+
+
+def test_index_corruption_with_old_hints(borg_env):
+    """Test that compact handles corrupted index (with old hints) gracefully."""
+    repo = borg_env['repo']
+
+    cmd('init', '--encryption=none', repo)
+    cmd('create', repo + '::archive1', 'input')
+
+    # Corrupt index
+    index_files = sorted([f for f in os.listdir(repo) if f.startswith('index.') and not f.endswith('.tmp')],
+                         key=lambda x: int(x.split('.')[1]))
+    index_path = os.path.join(repo, index_files[-1])
+
+    with open(index_path, 'wb') as f:
+        f.write(b'corrupted')
+
+    # Compact should succeed (with fix)
+    cmd('compact', repo)

src/borg/testsuite/repository.py

@@ -716,10 +716,13 @@ class RepositoryAuxiliaryCorruptionTestCase(RepositoryTestCaseBase):
         with self.repository:
             self.repository.append_only = False
             self.repository.put(H(3), b'1234')
-            # Do a compaction run. Fails, since the corrupted refcount was not detected and leads to an assertion failure.
-            with pytest.raises(AssertionError) as exc_info:
+            # Do a compaction run.
+            # The corrupted refcount is detected and logged as a warning, but compaction proceeds.
+            with self.assertLogs('borg.repository', level='WARNING') as cm:
                 self.repository.commit(compact=True)
-            assert 'Corrupted segment reference count' in str(exc_info.value)
+            assert any('Corrupted segment reference count' in msg for msg in cm.output)
+            # We verify that the repository is still consistent.
+            assert self.repository.check()
 
 
 class RepositoryCheckTestCase(RepositoryTestCaseBase):