• Duy Nguyen's avatar
    checkout: avoid unnecessary match_pathspec calls · e721c154
    Duy Nguyen authored
    In checkout_paths() we do this
    
     - for all updated items, call match_pathspec
     - for all items, call match_pathspec (inside unmerge_cache)
     - for all items, call match_pathspec (for showing "path .. is unmerged)
     - for updated items, call match_pathspec and update paths
    
    That's a lot of duplicate match_pathspec(s) and the function is not
    exactly cheap to be called so many times, especially on large indexes.
    This patch makes it call match_pathspec once per updated index entry,
    save the result in ce_flags and reuse the results in the following
    loops.
    
    The changes in 0a1283bc (checkout $tree $path: do not clobber local
    changes in $path not in $tree - 2011-09-30) limit the affected paths
    to ones we read from $tree. We do not do anything to other modified
    entries in this case, so the "for all items" above could be modified
    to "for all updated items". But..
    
    The command's behavior now is modified slightly: unmerged entries that
    match $path, but not updated by $tree, are now NOT touched.  Although
    this should be considered a bug fix, not a regression. A new test is
    added for this change.
    
    And while at there, free ps_matched after use.
    
    The following command is tested on webkit, 215k entries. The pattern
    is chosen mainly to make match_pathspec sweat:
    
    git checkout -- "*[a-zA-Z]*[a-zA-Z]*[a-zA-Z]*"
    
            before      after
    real    0m3.493s    0m2.737s
    user    0m2.239s    0m1.586s
    sys     0m1.252s    0m1.151s
    Signed-off-by: Duy Nguyen's avatarNguyễn Thái Ngọc Duy <pclouds@gmail.com>
    Signed-off-by: default avatarJunio C Hamano <gitster@pobox.com>
    e721c154
t2022-checkout-paths.sh 1.65 KB