Jonathan Nieder <jrnieder@xxxxxxxxx> writes: > We cannot change the past, but for index extensions of the future, > there is a straightforward improvement: silence that message except > when tracing. This way, the message is still available when > debugging, but in everyday use it does not show up so (once most Git > users have this patch) we can turn on new optional extensions right > away without alarming people. That argument ignores the "let the users know they are using a stale version when they did use (either by accident or deliberately) a more recent one" value, though. Even if we consider that this is only for debugging, I am not sure if tracing is the right place to add. As long as the "optional extensions can be ignored without affecting the correctness" rule holds, there is nothing gained by letting these messages shown for debugging purposes, and if there is such a bug (e.g. we introduced an optional extension but the code that wrote an index with an optional extension wrote the non-optional part in such a way that it cannot be correctly handled without the extension that is supposed to be optional) we'd probably want to let users notice without having to explicitly go into a debugging session. If Googling for "ignoring FNCY ext" gives "discard your index with 'reset HEAD', because an index file with FNCY ext cannot be read without understanding it", that may prevent damages from happening in the first place. On the other hand, hiding it behind tracing would mean the user first need to exprience an unknown breakage first and then has to enable tracing among other 47 different things to diagnose and drill down to the root cause.
