Re: "git-diff -p :/anything" always segfaults

Linus Torvalds [off-list ref] writes:

On Sun, 11 Mar 2007, Jim Meyering wrote:

quoted

I like the idea of the new ':/<oneline prefix>' notation, and gave it
a try, but all I could get was a segfault.  It was dereferencing a NULL
commit list.  Fix below.  With it, this example now works:

The fix is correct, but not complete.

quoted

-	while ((commit = pop_most_recent_commit(&list, ONELINE_SEEN))) {
+	while (list && (commit = pop_most_recent_commit(&list, ONELINE_SEEN))) {

The old code was broken, but the new one isn't much better.

"pop_most_recent_commit()" simply doesn't work that way. It *never* 
returns NULL. So having it as part of a while-loop was buggy to begin 
with, and you fixed the test, but the thing is, it should just look like

	while (list) {
		struct commit *commit;

		commit = pop_most_recent_commit(&list, ONELINE_SEEN);
		..

and the "pop_most_recent_commit()" simply shouldn't be part of the 
conditional at all.

That's what I did in my tentative commit based on Jim's patch
(except "commit" is also used to determine the return value from
the function).