Re: [PATCH] Re-re-re-fix common tail optimization

On Sun, Dec 16, 2007 at 01:49:17PM -0800, Junio C Hamano wrote:

Kind'a embarrassing that both of us cannot get this right without so
many rounds, isn't it?

Good thing we can just delete the emails and nobody will be the wiser...

+echo >expect <<\EOF

This would probably work better as 'cat'.

+test_expect_success 'diff -U0' '
+
+	git diff -U0 | sed -e "/^index/d" -e "s/$z2047/Z/g" >actual &&
+	diff -u expect actual

Aren't we using "git diff" for the second diff there nowadays?

-	while (recovered < trimmed && ctx)
+	while (recovered < trimmed && 0 <= ctx)
 		if (ap[recovered++] == '\n')
 			ctx--;
 	a->size -= (trimmed - recovered);

Oops (I think maybe I misunderstood what you were asking in the last
email). This fix is correct, though the code is now kind of subtle. I
think it would be more obvious as:

  /* finish off any changed line we are in */
  while (recovered < trimmed && ap[recovered++] != '\n')
    /* nothing */;
  /* recover context lines */
  while (recovered < trimmed && ctx)
    if (ap[recovered++] == '\n')
      ctx--;

Your loop does both actions in the same loop, which is correct, but took
me 10 minutes of thinking and staring to realize what was going on.

-Peff