Do not assert on diff if hard link sources are not found due to exclu…

…sions.

src/borg/archive.py

@@ -1038,7 +1038,7 @@ def chunk_decref(id, stats, part=False):
             logger.warning('borg check --repair is required to free all space.')
 
     @staticmethod
-    def compare_archives_iter(archive1, archive2, matcher=None, can_compare_chunk_ids=False, content_only=False):
+    def compare_archives_iter(print_warning, archive1, archive2, matcher=None, can_compare_chunk_ids=False, content_only=False):
         """
         Yields tuples with a path and an ItemDiff instance describing changes/indicating equality.
 
@@ -1117,10 +1117,16 @@ def defer_if_necessary(item1, item2):
             update_hardlink_masters(deleted, deleted_item)
             yield (path, compare_items(deleted, deleted_item))
         for item1, item2 in deferred:
-            assert hardlink_master_seen(item1)
-            assert hardlink_master_seen(item2)
             assert item1.path == item2.path, "Deferred items have different paths"
-            yield (item1.path, compare_items(item1, item2))
+            hl_notfound1 = not hardlink_master_seen(item1)
+            hl_notfound2 = not hardlink_master_seen(item2)
+            if hl_notfound1 or hl_notfound2:
+                if hl_notfound1:
+                    print_warning(f"cannot find hardlink source for {item1.path} ({item1.source}), skipping compare.")
+                if hl_notfound2:
+                    print_warning(f"cannot find hardlink source for {item2.path} ({item2.source}), skipping compare.")
+            else:
+                yield (item1.path, compare_items(item1, item2))
 
 
 class MetadataCollector:

src/borg/archiver.py

@@ -1162,7 +1162,7 @@ def print_text_output(diff, path):
 
         matcher = self.build_matcher(args.patterns, args.paths)
 
-        diffs = Archive.compare_archives_iter(archive1, archive2, matcher, can_compare_chunk_ids=can_compare_chunk_ids, content_only=args.content_only)
+        diffs = Archive.compare_archives_iter(self.print_warning, archive1, archive2, matcher, can_compare_chunk_ids=can_compare_chunk_ids, content_only=args.content_only)
         # Conversion to string and filtering for diff.equal to save memory if sorting
         diffs = ((path, diff.changes()) for path, diff in diffs if not diff.equal)