Re: [PATCH 09/19] documentation: add documentation for the bitmap format

On Fri, Oct 25, 2013 at 10:21 AM, Jeff King [off-list ref] wrote:

But if you want to simply add extra
data that would be ignored by an existing implementation, it would be OK
to add the data and mark it with a flag:

quoted

quoted

+               2-byte flags (network byte order)
+
+                       The following flags are supported:

[...]

That's how we added the name-hash cache in the final patch.

That being said, JGit is _not_ happy with that, and complains when any
flags besides OPT_FULL are used.  Whether that is because I am
misinterpreting the intent of the flags field, or because JGit is being
overly strict is up for debate.

Might be a good idea to support two classes of flags like how
extensions are handled in the index: ignore unrecognized uppercase
extension names, barf on unrecongized lowercase names. We could
partition the flag bit space more or less the same way.
-- 
Duy