Re: [PATCH v3 3/3] builtin/grep.c: walking tree instead of expanding index with --sparse

[Shaoxuan Yuan <shaoxuan.yuan02@gmail.com>]

On 9/1/2022 10:27 AM, Junio C Hamano wrote:
 > Junio C Hamano <gitster@pobox.com> writes:
 >
 >> Shaoxuan Yuan <shaoxuan.yuan02@gmail.com> writes:
 >>
 >>> Before this patch, whenever --sparse is used, `git-grep` utilizes the
 >>> ensure_full_index() method to expand the index and search all the
 >>> entries. Because this method requires walking all the trees and
 >>> constructing the index, it is the slow part within the whole command.
 >>>
 >>> To achieve better performance, this patch uses grep_tree() to 
search the
 >>> sparse directory entries and get rid of the ensure_full_index() method.
 >>
 >> When you encounter a "sparsedir" (i.e. a tree recorded in index),
 >> you should know the path leading to that directory. Even though I no
 >> longer remember the details of the implementations of grep_$where()
 >> which I did long time ago, I think grep_tree() should know how to
 >> pass the leading path down, as that is the most natural way to
 >> implement the recursive behaviour.  This patch should be able to
 >> piggyback on that.
 >
 > To avoid unnecessary scare, the above is just me "thinking aloud",
 > after reading the proposed log message, and agreeing with the
 > direction taken by this patch.  Not giving a suggestion to go
 > different route or anything like that.  I should have said "OK" or
 > something at the end of the paragraph.
 >
 > Thanks for working on this topic.

Thank you! :-)