[RFC/PATCH 3/3] push: add separate 'downstream' branch

@@ -76,21 +76,23 @@ static int push_url_of_remote(struct remote *remote, const char ***url_p)
 	return remote->url_nr;
 }
 
-static NORETURN int die_push_simple(struct branch *branch, struct remote *remote) {
+static NORETURN int die_push_simple(struct branch *branch, struct remote *remote,
+		const char *kind, const char *related)
+{
 	/*
 	 * There's no point in using shorten_unambiguous_ref here,
 	 * as the ambiguity would be on the remote side, not what
 	 * we have locally. Plus, this is supposed to be the simple
 	 * mode. If the user is doing something crazy like setting
-	 * upstream to a non-branch, we should probably be showing
+	 * upstream/downstream to a non-branch, we should probably be showing
 	 * them the big ugly fully qualified ref.
 	 */
 	const char *advice_maybe = "";
-	const char *short_upstream =
-		skip_prefix(branch->merge[0]->src, "refs/heads/");
+	const char *short_upstream = skip_prefix(related, "refs/heads/");
 
 	if (!short_upstream)
-		short_upstream = branch->merge[0]->src;
+		short_upstream = related;
+
 	/*
 	 * Don't show advice for people who explicitely set
 	 * push.default.

@@ -99,8 +101,8 @@ static NORETURN int die_push_simple(struct branch *branch, struct remote *remote
 		advice_maybe = _("\n"
 				 "To choose either option permanently, "
 				 "see push.default in 'git help config'.");
-	die(_("The upstream branch of your current branch does not match\n"
-	      "the name of your current branch.  To push to the upstream branch\n"
+	die(_("The %s branch of your current branch does not match\n"
+	      "the name of your current branch.  To push to the %s branch\n"
 	      "on the remote, use\n"
 	      "\n"
 	      "    git push %s HEAD:%s\n"

@@ -109,6 +111,7 @@ static NORETURN int die_push_simple(struct branch *branch, struct remote *remote
 	      "\n"
 	      "    git push %s %s\n"
 	      "%s"),
+	    kind, kind,
 	    remote->name, short_upstream,
 	    remote->name, branch->name, advice_maybe);
 }

@@ -117,6 +120,8 @@ static void setup_push_upstream(struct remote *remote, int simple)
 {
 	struct strbuf refspec = STRBUF_INIT;
 	struct branch *branch = branch_get(NULL);
+	const char *related, *kind, *pushremote_name;
+
 	if (!branch)
 		die(_("You are not currently on a branch.\n"
 		    "To push the history leading to the current (detached HEAD)\n"

@@ -124,26 +129,38 @@ static void setup_push_upstream(struct remote *remote, int simple)
 		    "\n"
 		    "    git push %s HEAD:<name-of-remote-branch>\n"),
 		    remote->name);
-	if (!branch->merge_nr || !branch->merge || !branch->remote_name)
-		die(_("The current branch %s has no upstream branch.\n"
-		    "To push the current branch and set the remote as upstream, use\n"
-		    "\n"
-		    "    git push --set-upstream %s %s\n"),
-		    branch->name,
-		    remote->name,
-		    branch->name);
-	if (branch->merge_nr != 1)
-		die(_("The current branch %s has multiple upstream branches, "
-		    "refusing to push."), branch->name);
-	if (strcmp(branch->remote_name, remote->name))
-		die(_("You are pushing to remote '%s', which is not the upstream of\n"
+
+	if (branch->push) {
+		kind = _("downstream");
+		related = branch->push;
+		pushremote_name = branch->pushremote_name;
+	} else {
+		if (!branch->merge_nr || !branch->merge || !branch->remote_name)
+			die(_("The current branch %s has no upstream branch.\n"
+			    "To push the current branch and set the remote as upstream, use\n"
+			    "\n"
+			    "    git push --set-upstream %s %s\n"),
+			    branch->name,
+			    remote->name,
+			    branch->name);
+		if (branch->merge_nr != 1)
+			die(_("The current branch %s has multiple upstream branches, "
+			    "refusing to push."), branch->name);
+
+		kind = _("upstream");
+		related = branch->merge[0]->src;
+		pushremote_name = branch->remote_name;
+	}
+
+	if (strcmp(pushremote_name, remote->name))
+		die(_("You are pushing to remote '%s', which is not the %s of\n"
 		      "your current branch '%s', without telling me what to push\n"
 		      "to update which remote branch."),
-		    remote->name, branch->name);
-	if (simple && strcmp(branch->refname, branch->merge[0]->src))
-		die_push_simple(branch, remote);
+		    remote->name, kind, branch->name);
+	if (simple && strcmp(branch->refname, related))
+		die_push_simple(branch, remote, kind, related);
 
-	strbuf_addf(&refspec, "%s:%s", branch->name, branch->merge[0]->src);
+	strbuf_addf(&refspec, "%s:%s", branch->name, related);
 	add_refspec(refspec.buf);
 }
 

@@ -365,13 +365,17 @@ static int handle_config(const char *key, const char *value, void *cb)
 				explicit_default_remote_name = 1;
 			}
 		} else if (!strcmp(subkey, ".pushremote")) {
+			if (git_config_string(&branch->pushremote_name, key, value))
+				return -1;
 			if (branch == current_branch)
-				if (git_config_string(&pushremote_name, key, value))
-					return -1;
+				pushremote_name = xstrdup(branch->pushremote_name);
 		} else if (!strcmp(subkey, ".merge")) {
 			if (!value)
 				return config_error_nonbool(key);
 			add_merge(branch, xstrdup(value));
+		} else if (!strcmp(subkey, ".push")) {
+			if (git_config_string(&branch->push, key, value))
+				return -1;
 		}
 		return 0;
 	}

@@ -138,6 +138,9 @@ struct branch {
 	struct refspec **merge;
 	int merge_nr;
 	int merge_alloc;
+
+	const char *pushremote_name;
+	const char *push;
 };
 
 struct branch *branch_get(const char *name);