[PATCH v3 2/5] push: add advice for rejected tag reference

[Chris Rorvick <chris@rorvick.com>]

Advising the user to fetch and merge only makes sense if the rejected
reference is a branch.  If none of the rejections were for branches,
tell the user they need to force the update(s).

Signed-off-by: Chris Rorvick <chris@rorvick.com>
---
 builtin/push.c | 16 ++++++++++++++--
 cache.h        |  1 +
 remote.c       |  7 +++++++
 transport.c    |  6 ++++--
 transport.h    |  5 +++--
 5 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/builtin/push.c b/builtin/push.c
index eaeaf7e..77340c0 100644
--- a/builtin/push.c
+++ b/builtin/push.c
@@ -220,6 +220,11 @@ static const char message_advice_checkout_pull_push[] =
 	   "(e.g. 'git pull') before pushing again.\n"
 	   "See the 'Note about fast-forwards' in 'git push --help' for details.");
 
+static const char message_advice_ref_already_exists[] =
+	N_("Updates were rejected because a matching reference already exists in\n"
+	   "the remote and the update is not a fast-forward.  Use git push -f if\n"
+	   "you really want to make this update.");
+
 static void advise_pull_before_push(void)
 {
 	if (!advice_push_non_ff_current || !advice_push_nonfastforward)
@@ -241,6 +246,11 @@ static void advise_checkout_pull_push(void)
 	advise(_(message_advice_checkout_pull_push));
 }
 
+static void advise_ref_already_exists(void)
+{
+	advise(_(message_advice_ref_already_exists));
+}
+
 static int push_with_options(struct transport *transport, int flags)
 {
 	int err;
@@ -265,13 +275,15 @@ static int push_with_options(struct transport *transport, int flags)
 	if (!err)
 		return 0;
 
-	if (reject_mask & NON_FF_HEAD) {
+	if (reject_mask & REJECT_NON_FF_HEAD) {
 		advise_pull_before_push();
-	} else if (reject_mask & NON_FF_OTHER) {
+	} else if (reject_mask & REJECT_NON_FF_OTHER) {
 		if (default_matching_used)
 			advise_use_upstream();
 		else
 			advise_checkout_pull_push();
+	} else if (reject_mask & REJECT_ALREADY_EXISTS) {
+		advise_ref_already_exists();
 	}
 
 	return 1;
diff --git a/cache.h b/cache.h
index dbd8018..4e25840 100644
--- a/cache.h
+++ b/cache.h
@@ -1002,6 +1002,7 @@ struct ref {
 	unsigned int force:1,
 		merge:1,
 		nonfastforward:1,
+		forwardable:1,
 		deletion:1;
 	enum {
 		REF_STATUS_NONE = 0,
diff --git a/remote.c b/remote.c
index 04fd9ea..5ecd58d 100644
--- a/remote.c
+++ b/remote.c
@@ -1316,6 +1316,13 @@ void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
 		 *     always allowed.
 		 */
 
+		if (prefixcmp(ref->name, "refs/tags/")) {
+			struct object *old = parse_object(ref->old_sha1);
+			struct object *new = parse_object(ref->new_sha1);
+			ref->forwardable = (old && new &&
+			  old->type == OBJ_COMMIT && new->type == OBJ_COMMIT);
+		}
+
 		ref->nonfastforward =
 			!ref->deletion &&
 			!is_null_sha1(ref->old_sha1) &&
diff --git a/transport.c b/transport.c
index ae9fda8..1657798 100644
--- a/transport.c
+++ b/transport.c
@@ -740,10 +740,12 @@ void transport_print_push_status(const char *dest, struct ref *refs,
 		    ref->status != REF_STATUS_OK)
 			n += print_one_push_status(ref, dest, n, porcelain);
 		if (ref->status == REF_STATUS_REJECT_NONFASTFORWARD) {
+			if (!ref->forwardable)
+				*reject_mask |= REJECT_ALREADY_EXISTS;
 			if (!strcmp(head, ref->name))
-				*reject_mask |= NON_FF_HEAD;
+				*reject_mask |= REJECT_NON_FF_HEAD;
 			else
-				*reject_mask |= NON_FF_OTHER;
+				*reject_mask |= REJECT_NON_FF_OTHER;
 		}
 	}
 }
diff --git a/transport.h b/transport.h
index 1f9699c..7e86352 100644
--- a/transport.h
+++ b/transport.h
@@ -140,8 +140,9 @@ int transport_set_option(struct transport *transport, const char *name,
 void transport_set_verbosity(struct transport *transport, int verbosity,
 	int force_progress);
 
-#define NON_FF_HEAD     0x01
-#define NON_FF_OTHER    0x02
+#define REJECT_NON_FF_HEAD     0x01
+#define REJECT_NON_FF_OTHER    0x02
+#define REJECT_ALREADY_EXISTS  0x04
 
 int transport_push(struct transport *connection,
 		   int refspec_nr, const char **refspec, int flags,
-- 
1.8.0