view tests/test-up-issue1456 @ 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.

#!/bin/sh

rm -rf a
hg init a
cd a

echo foo > foo
hg ci -qAm0
chmod +x foo
hg ci -m1
hg co -q 0
echo dirty > foo
sleep 1
hg up -q
cat foo
hg st -A

echo '% validate update of standalone execute bit change'
hg up -C 0
chmod -x foo
hg ci -m removeexec
hg up -C 0
hg up
hg st