Re: [PATCH 1/5] eoie: default to not writing EOIE section

[Ben Peart <peartben@gmail.com>]

On 11/20/2018 1:11 AM, Jonathan Nieder wrote:
> Since 3b1d9e04 (eoie: add End of Index Entry (EOIE) extension,
> 2018-10-10) Git defaults to writing the new EOIE section when writing
> out an index file.  Usually that is a good thing because it improves
> threaded performance, but when a Git repository is shared with older
> versions of Git, it produces a confusing warning:
> 
>    $ git status
>    ignoring EOIE extension
>    HEAD detached at 371ed0defa
>    nothing to commit, working tree clean
> 
> Let's introduce the new index extension more gently.  First we'll roll
> out the new version of Git that understands it, and then once
> sufficiently many users are using such a version, we can flip the
> default to writing it by default.
> 
> Introduce a '[index] recordEndOfIndexEntries' configuration variable
> to allow interested users to benefit from this index extension early.
> 
> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
> ---
> Rebased.  No other change from v1.
> 
> As Jonathan pointed out, it would be nice to have tests here.  Ben,
> any advice for how I could write some in a followup change?  E.g. does
> Derrick Stolee's tracing based testing trick apply here?
> 

I suppose a 'test-dump-eoie' could be written along the lines of 
test-dump-fsmonitor or test-dump-untracked-cache.  Unlike those, there 
isn't much state to dump other than the existence of the extension and 
the offset.  That could be used to test that the new settings are 
working properly.