[PATCH 1/2 v2] push: better error messages when push.default = tracking

[Matthieu Moy <Matthieu.Moy@imag.fr>]

A common scenario is to create a new branch and push it (checkout -b &&
push [--set-upstream]). In this case, the user was getting "The current
branch %s has no upstream branch.", which doesn't help much.

Provide the user a command to push the current branch. To avoid the
situation in the future, suggest --set-upstream.

While we're there, also improve the error message in the "detached HEAD"
case. We mention explicitly "detached HEAD" since this is the keyword to
look for in documentations.

Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
---
Compared to v1, the detached HEAD case joined this patch since it
became semantically linked (requires the "remote" extra parameter),
and doesn't mention the possibility to checkout another branch before
pushing it (cf. Junio).

 builtin/push.c |   21 +++++++++++++++------
 1 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/builtin/push.c b/builtin/push.c
index 31da418..c949187 100644
--- a/builtin/push.c
+++ b/builtin/push.c
@@ -64,14 +64,23 @@ static void set_refspecs(const char **refs, int nr)
 	}
 }
 
-static void setup_push_upstream(void)
+static void setup_push_upstream(struct remote *remote)
 {
 	struct strbuf refspec = STRBUF_INIT;
 	struct branch *branch = branch_get(NULL);
 	if (!branch)
-		die("You are not currently on a branch.");
+		die("You are not currently on a branch (detached HEAD).\n"
+		    "To push a specific branch and set the remote as upstream, use\n"
+		    "\n"
+		    "    git push --set-upstream %s <branch-name>\n",
+		    remote->name);
 	if (!branch->merge_nr || !branch->merge)
-		die("The current branch %s has no upstream branch.",
+		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, "
@@ -80,7 +89,7 @@ static void setup_push_upstream(void)
 	add_refspec(refspec.buf);
 }
 
-static void setup_default_push_refspecs(void)
+static void setup_default_push_refspecs(struct remote *remote)
 {
 	switch (push_default) {
 	default:
@@ -89,7 +98,7 @@ static void setup_default_push_refspecs(void)
 		break;
 
 	case PUSH_DEFAULT_UPSTREAM:
-		setup_push_upstream();
+		setup_push_upstream(remote);
 		break;
 
 	case PUSH_DEFAULT_CURRENT:
@@ -175,7 +184,7 @@ static int do_push(const char *repo, int flags)
 			refspec = remote->push_refspec;
 			refspec_nr = remote->push_refspec_nr;
 		} else if (!(flags & TRANSPORT_PUSH_MIRROR))
-			setup_default_push_refspecs();
+			setup_default_push_refspecs(remote);
 	}
 	errs = 0;
 	if (remote->pushurl_nr) {
-- 
1.7.4.1.142.ge03e1