Re: [PATCH 3/2] Enhance --early-output format

Linus Torvalds [off-list ref] writes:

It wasn't totally trivial, but it doesn't seem to be excessively subtle 
either. About half the patch is moving around some code to look at whether 
the commit is interesting or not and rewriting the parents, so that it can 
be shared with the revision walker.

Very nicely done.

+	while (list) {
+		struct commit *commit = list->item;
+		unsigned int flags = commit->object.flags;
+
+		list = list->next;
+		if (flags & UNINTERESTING)
+			continue;
+		if (rev->prune_fn && rev->dense && !(flags & TREECHANGE)) {
+			if (commit->parents && !commit->parents->next)
+				continue;
+		}

When looking at:

	if (A && B && C) {
        	if (D && E)
                	continue;
	}

an uninitiated might say "Huh?  Why use nested 'if'?", but to
somebody who knows how revision traversal works, the above split
is a more logical way to test this condition.  Maybe one liner
comment is in order?

+static void show_early_header(struct rev_info *rev, const char *stage, int nr)
+{
+	if (rev->shown_one) {
+		rev->shown_one = 0;
+		if (rev->commit_format != CMIT_FMT_ONELINE)
+			putchar(rev->diffopt.line_termination);
+	}
+	printf("Final output: %d %s\n", nr, stage);
+}

As you noted, this is more like "Partial output" now.
How about painting the bikeshed pink by saying:

	Partial output: 20
        Partial output: 70
        Final output: 70000

+	/* Did we already get enough commits for the early output? */
+	if (!i)
+		return;
+
+	/*
+	 * ..if no, then repeat it twice a second until we
+	 * do.
+	 *
+	 * NOTE! We don't use "it_interval", because if the
+	 * reader isn't listening, we want our output to be
+	 * throttled by the writing, and not have the timer
+	 * trigger every second even if we're blocked on a
+	 * reader!
+	 */

A comment like this is very much appreciated.

+	early_output_timer.it_value.tv_sec = 0;
+	early_output_timer.it_value.tv_usec = 500000;
+	setitimer(ITIMER_REAL, &early_output_timer, NULL);
 }