misleading diff-hunk header

[posted originally to git-users@ but advised this would be a better
forum]

diff.{type}.xfuncname seems to start searching backwards in
from the beginning of the hunk, not the first differing line.

To reproduce:

  $ mkdir tmp
  $ cd tmp
  $ git init
  $ cat > foo.c <<EOF
  int call_me(int maybe)
  {
  }

  int main()
  {
  }
  EOF
  $ git add foo.c
  $ git commit -m "Initial checkin"
  $ ed foo.c
  # main() should return 0
  $i
    return 0;
  .
  wq
  $ git diff

The diff returns a header line of

  @@ -4,4 +4,5 @@ int call_me(int maybe)

   int main()
   {
  +  return 0;
   }

misleadingly suggesting that the change occurred in the call_me()
function, rather than in main()

I'm running 1.7.2.5 from Debian Stable if that makes a difference.

Is this expected/proper behavior?

-tkc

FWIW, I stumbled across this tinkering with
diff.{typename}.xfuncname detailed in gitattributes(5)