view tests/test-pull-r.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.

changeset:   2:effea6de0384
tag:         tip
parent:      0:bbd179dfa0a7
user:        test
date:        Thu Jan 01 00:00:00 1970 +0000
summary:     add bar

changeset:   1:ed1b79f46b9a
user:        test
date:        Thu Jan 01 00:00:00 1970 +0000
summary:     change foo

changeset:   0:bbd179dfa0a7
user:        test
date:        Thu Jan 01 00:00:00 1970 +0000
summary:     add foo

% pull a missing revision
abort: unknown revision 'missing'!
% pull -r 0
changeset:   0:bbd179dfa0a7
tag:         tip
user:        test
date:        Thu Jan 01 00:00:00 1970 +0000
summary:     add foo

% pull -r 1
changeset:   1:ed1b79f46b9a
tag:         tip
user:        test
date:        Thu Jan 01 00:00:00 1970 +0000
summary:     change foo

changeset:   0:bbd179dfa0a7
user:        test
date:        Thu Jan 01 00:00:00 1970 +0000
summary:     add foo

% pull -r 1 again