Re: [PATCH v3 03/10] progress.c tests: make start/stop verbs on stdin

On Fri, Oct 22, 2021 at 04:18:16PM +0200, Ævar Arnfjörð Bjarmason wrote:

quoted

quoted

 	progress_testing = 1;
-	progress = start_progress(title, total);
 	while (strbuf_getline(&line, stdin) != EOF) {
 		char *end;

-		if (skip_prefix(line.buf, "progress ", (const char **) &end)) {
+		if (skip_prefix(line.buf, "start ", (const char **) &end)) {
+			uint64_t total = strtoull(end, &end, 10);
+			if (*end == '\0') {
+				progress = start_progress(default_title, total);
+			} else if (*end == ' ') {
+				item = string_list_insert(&list, end + 1);
+				progress = start_progress(item->string, total);

Why is it necessary to use a string_list here?  This is the only place
where it is used, so I don't understand why we should store anything
in it.

The progress.c API doesn't xstrdup() the title you give it, so you can't
free() it after while it's alive.

Here we're re-setting the same strbuf in a loop, so if we hand a "title"
to progress.c we need to keep it around, when we later add a BUG
assertion in 10/10:

+	if (global_progress)
+		BUG("'%s' progress still active when trying to start '%s'",
+		    global_progress->title, progress->title);
+	global_progress = progress;

The "old" title would point to already-free'd or to a nonsensical value
if we didn't do that.

*nod*. I figured as much, but a comment indicating that may be helpful
for reviewers and future readers of this code.

Thanks,
Taylor