view tests/test-issue522 @ 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

# In the merge below, the file "foo" has the same contents in both
# parents, but if we look at the file-level history, we'll notice that
# the version in p1 is an ancestor of the version in p2.  This test
# makes sure that we'll use the version from p2 in the manifest of the
# merge revision.

hg init repo
cd repo

echo foo > foo
hg ci -qAm 'add foo'

echo bar >> foo
hg ci -m 'change foo'

hg backout -r tip -m 'backout changed foo'

hg up -C 0
touch bar
hg ci -qAm 'add bar'

hg merge --debug
hg debugstate | grep foo
hg st -A foo
hg ci -m 'merge'

hg manifest --debug | grep foo
hg debugindex .hg/store/data/foo.i