Merge branch 'jc/push-upstream-sanity' into maint

The 'push to upstream' implementation was broken in some corner
cases. "git push $there" without refspec, when the current branch is
set to push to a remote different from $there, used to push to $there
using the upstream information to a remote unreleated to $there.

* jc/push-upstream-sanity:
  push: error out when the "upstream" semantics does not make sense

builtin/push.c

@@ -65,6 +65,16 @@ static void set_refspecs(const char **refs, int nr)
 	}
 }
 
+static int push_url_of_remote(struct remote *remote, const char ***url_p)
+{
+	if (remote->pushurl_nr) {
+		*url_p = remote->pushurl;
+		return remote->pushurl_nr;
+	}
+	*url_p = remote->url;
+	return remote->url_nr;
+}
+
 static void setup_push_upstream(struct remote *remote)
 {
 	struct strbuf refspec = STRBUF_INIT;
@@ -76,7 +86,7 @@ static void setup_push_upstream(struct remote *remote)
 		    "\n"
 		    "    git push %s HEAD:<name-of-remote-branch>\n"),
 		    remote->name);
-	if (!branch->merge_nr || !branch->merge)
+	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"
@@ -87,6 +97,12 @@ static void setup_push_upstream(struct remote *remote)
 	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"
+		      "your current branch '%s', without telling me what to push\n"
+		      "to update which remote branch."),
+		    remote->name, branch->name);
+
 	strbuf_addf(&refspec, "%s:%s", branch->name, branch->merge[0]->src);
 	add_refspec(refspec.buf);
 }
@@ -196,13 +212,7 @@ static int do_push(const char *repo, int flags)
 			setup_default_push_refspecs(remote);
 	}
 	errs = 0;
-	if (remote->pushurl_nr) {
-		url = remote->pushurl;
-		url_nr = remote->pushurl_nr;
-	} else {
-		url = remote->url;
-		url_nr = remote->url_nr;
-	}
+	url_nr = push_url_of_remote(remote, &url);
 	if (url_nr) {
 		for (i = 0; i < url_nr; i++) {
 			struct transport *transport =

t/t5528-push-default.sh

@@ -0,0 +1,54 @@
+#!/bin/sh
+
+test_description='check various push.default settings'
+. ./test-lib.sh
+
+test_expect_success 'setup bare remotes' '
+	git init --bare repo1 &&
+	git remote add parent1 repo1 &&
+	git init --bare repo2 &&
+	git remote add parent2 repo2 &&
+	test_commit one &&
+	git push parent1 HEAD &&
+	git push parent2 HEAD
+'
+
+test_expect_success '"upstream" pushes to configured upstream' '
+	git checkout master &&
+	test_config branch.master.remote parent1 &&
+	test_config branch.master.merge refs/heads/foo &&
+	test_config push.default upstream &&
+	test_commit two &&
+	git push &&
+	echo two >expect &&
+	git --git-dir=repo1 log -1 --format=%s foo >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success '"upstream" does not push on unconfigured remote' '
+	git checkout master &&
+	test_unconfig branch.master.remote &&
+	test_config push.default upstream &&
+	test_commit three &&
+	test_must_fail git push
+'
+
+test_expect_success '"upstream" does not push on unconfigured branch' '
+	git checkout master &&
+	test_config branch.master.remote parent1 &&
+	test_unconfig branch.master.merge &&
+	test_config push.default upstream
+	test_commit four &&
+	test_must_fail git push
+'
+
+test_expect_success '"upstream" does not push when remotes do not match' '
+	git checkout master &&
+	test_config branch.master.remote parent1 &&
+	test_config branch.master.merge refs/heads/foo &&
+	test_config push.default upstream &&
+	test_commit five &&
+	test_must_fail git push parent2
+'
+
+test_done