Re: What's cooking in git.git (Aug 2018, #04; Fri, 17)

[Duy Nguyen <pclouds@gmail.com>]

On Sat, Aug 18, 2018 at 12:44 AM Junio C Hamano <gitster@pobox.com> wrote:
> * nd/unpack-trees-with-cache-tree (2018-08-13) 5 commits
>  - unpack-trees: reuse (still valid) cache-tree from src_index
>  - unpack-trees: reduce malloc in cache-tree walk
>  - unpack-trees: optimize walking same trees with cache-tree
>  - unpack-trees: add performance tracing
>  - trace.h: support nested performance tracing
>
>  The unpack_trees() API used in checking out a branch and merging
>  walks one or more trees along with the index.  When the cache-tree
>  in the index tells us that we are walking a tree whose flattened
>  contents is known (i.e. matches a span in the index), as linearly
>  scanning a span in the index is much more efficient than having to
>  open tree objects recursively and listing their entries, the walk
>  can be optimized, which is done in this topic.
>
>  Will merge to and cook in 'next'.

Please hold.

I was going to address your "The last step feels a bit scary" comment
by auditing and adding some cache-tree validation. I'm seeing some bad
cache-tree when running more validation through the test suite. Maybe
it's just bugs in my validation code, but better be safe than sorry.
-- 
Duy