view tests/test-diff-unified @ 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

hg init repo
cd repo
cat > a <<EOF
c
c
a
a
b
a
a
c
c
EOF
hg ci -Am adda
cat > a <<EOF
c
c
a
a
dd
a
a
c
c
EOF

echo '% default context'
hg diff --nodates

echo '% invalid --unified'
hg diff --nodates -U foo

echo '% --unified=2'
hg diff --nodates -U 2

echo '% diff.unified=2'
hg --config diff.unified=2 diff --nodates

echo '% diff.unified=2 --unified=1'
hg diff --nodates -U 1

echo '% invalid diff.unified'
hg --config diff.unified=foo diff --nodates

echo % test off-by-one error with diff -p
hg init diffp
cd diffp
echo a > a
hg ci -Ama
rm a
echo b > a
echo a >> a
echo c >> a
hg diff -U0 -p --nodates

exit 0