Re: [PATCH v8 1/3] branch: accept multiple upstream branches for tracking

Junio C Hamano [off-list ref] writes:

quoted

+/**
+ * Install upstream tracking configuration for a branch; specifically, add
+ * `branch.<name>.remote` and `branch.<name>.merge` entries.
+ *
+ * `flag` contains integer flags for options; currently only
+ * BRANCH_CONFIG_VERBOSE is checked.
+ *
+ * `local` is the name of the branch whose configuration we're installing.
+ *
+ * `origin` is the name of the remote owning the upstream branches. NULL means
+ * the upstream branches are local to this repo.
+ *
+ * `remotes` is a list of refs that are upstream of local
+ */
+static int install_branch_config_multiple_remotes(int flag, const char *local,
+		const char *origin, struct string_list *remotes)
 {
 	const char *shortname = NULL;
 	struct strbuf key = STRBUF_INIT;
+	struct string_list_item *item;
 	int rebasing = should_setup_rebase(origin);
 
+	if (!remotes->nr)
+		BUG("must provide at least one remote for branch config");
+	if (rebasing && remotes->nr > 1)
+		die(_("cannot inherit upstream tracking configuration of "
+		      "multiple refs when rebasing is requested"));
+
+	/*
+	 * If the new branch is trying to track itself, something has gone
+	 * wrong. Warn the user and don't proceed any further.
+	 */
+	if (!origin)
+		for_each_string_list_item(item, remotes)
+			if (skip_prefix(item->string, "refs/heads/", &shortname)
+			    && !strcmp(local, shortname)) {
+				warning(_("not setting branch '%s' as its own upstream."),
+					local);
+				return 0;
+			}

Added comments make it easier to follow what is going on and more
importantly why.  I very much like it ;-)

Agreed! We made a lot of 'why' decisions and I think the comments do a
great job of capturing that.

quoted

@@ -87,29 +117,40 @@ int install_branch_config(int flag, const char *local, const char *origin, const
 	strbuf_release(&key);
 
 	if (flag & BRANCH_CONFIG_VERBOSE) {
+		struct strbuf tmp_ref_name = STRBUF_INIT;
+		struct string_list friendly_ref_names = STRING_LIST_INIT_DUP;
+
+		for_each_string_list_item(item, remotes) {
+			shortname = item->string;
+			skip_prefix(shortname, "refs/heads/", &shortname);
+			if (origin) {
+				strbuf_addf(&tmp_ref_name, "%s/%s",
+					    origin, shortname);
+				string_list_append_nodup(
+					&friendly_ref_names,
+					strbuf_detach(&tmp_ref_name, NULL));
+			} else {
+				string_list_append(
+					&friendly_ref_names, shortname);
+			}
+		}
+
+		if (remotes->nr == 1) {
+			/*
+			 * Rebasing is only allowed in the case of a single
+			 * upstream branch.
+			 */

There does not seem to be any code to forbid "rebasing" when
remotes->nr != 1, though.  Did I miss a call to die() earlier?

The die() call happens in install_branch_config_multiple_remotes(),
where it belongs.

I think someone who reads this comment will eventually track down the
die() call, but it does look a little out of place. Purely as a matter
of personal taste, I would have expected this comment to be in the
'else' clause, and it might read something like:

  install_branch_config_multiple_remotes() does not allow rebasing with
  multiple upstream branches.

but that's just a suggestion :) This patch looks fine to me.

quoted

+			printf_ln(rebasing ?
+				_("branch '%s' set up to track '%s' by rebasing.") :
+				_("branch '%s' set up to track '%s'."),
+				local, friendly_ref_names.items[0].string);
 		} else {
+			printf_ln(_("branch '%s' set up to track:"), local);
+			for_each_string_list_item(item, &friendly_ref_names)
+				printf_ln("  %s", item->string);

In other words, I would have expected something in this else clause.

quoted

 		}

Thanks.