view tests/test-empty-file.out @ 8849:80cc4b1a62d0

compare grep result between target and its parent

I found that typical case is that grep target is added at (*) revision
in the tree shown below.

     +--- 1(*) --- 3
     0
     +--- 2 ------ 4

Now, I expect 'hg grep --all' to show only rev:1 which is first
appearance of target line.

But 'hg grep --all' will tell:

  target line dis-appeared at 3 => 4
  target line     appeared at 2 => 3
  target line dis-appeared at 1 => 2
  target line     appeared at 0 => 1

because current 'hg grep' implementation compares not between target
revision and its parent, but between neighbor revisions in walkthrough
order.

I checked performance of this patch by "hg grep --follow --all
walkchangerevs" on whole Mercurial repo, and patched version could
complete as fast as un-patched one.

0 files updated, 0 files merged, 1 files removed, 0 files unresolved
created new head
changeset:   2:62ec0e86d1e5
tag:         tip
parent:      0:567dde5e6e98
user:        test
date:        Mon Jan 12 13:46:40 1970 +0000
summary:     add empty3

changeset:   1:41ab7b321727
user:        test
date:        Mon Jan 12 13:46:40 1970 +0000
summary:     add empty2

1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
M empty2
b80de5d138758541c5f05265ad144ab9fa86d1db 644   empty1
b80de5d138758541c5f05265ad144ab9fa86d1db 644   empty2
b80de5d138758541c5f05265ad144ab9fa86d1db 644   empty3