iilyak commented on code in PR #5611:
URL: https://github.com/apache/couchdb/pull/5611#discussion_r2257086153
##########
src/couch/src/couch_bt_engine_header.erl:
##########
@@ -204,17 +204,16 @@ upgrade_tuple(Old) when is_record(Old, db_header) ->
Old;
upgrade_tuple(Old) when is_tuple(Old) ->
NewSize = record_info(size, db_header),
- if
- tuple_size(Old) < NewSize -> ok;
- true -> erlang:error({invalid_header_size, Old})
- end,
- {_, New} = lists:foldl(
- fun(Val, {Idx, Hdr}) ->
- {Idx + 1, setelement(Idx, Hdr, Val)}
+ Upgrade = tuple_size(Old) < NewSize,
+ ProhibitDowngrade = config:get_boolean("couchdb", "prohibit_downgrade",
true),
+ OldKVs =
+ case {Upgrade, ProhibitDowngrade} of
+ {true, AnyBool} when is_boolean(AnyBool) -> tuple_to_list(Old);
+ {false, true} -> error({invalid_header_size, Old});
+ {false, false} -> lists:sublist(tuple_to_list(Old), NewSize)
Review Comment:
The `NewSize` is greater than the size of the tuple, which means the
`lists:sublist` invocation would return the same tuple.
```erlang
Upgrade = tuple_size(Old) < NewSize,
...
{false, false} -> lists:sublist(tuple_to_list(Old), NewSize)
```
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: notifications-unsubscr...@couchdb.apache.org
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org
