[PATCH RFC] builtin-push: add --delete as syntactic sugar for :foo

["Jan Krüger" <jk@jk.gs>]

Refspecs without a source side have been reported as confusing by many.
As an alternative, this adds support for commands like:

    git push origin --delete somebranch

Specifically, --delete will prepend a colon to all colon-less refspecs
given on the command line.

Signed-off-by: Jan Krüger <jk@jk.gs>
---
Since I consider this extension pure syntactic sugar, it doesn't change
the underlying transport code. As such it's a relatively non-invasive
change.

One might imagine a different implementation that supports combining
--delete with --all and/or --tags, but perhaps it's better if people
are forced to do that kind of thing manually.

 builtin-push.c        |   15 +++++++++++++++
 t/t5516-fetch-push.sh |    6 ++++++
 2 files changed, 21 insertions(+), 0 deletions(-)

diff --git a/builtin-push.c b/builtin-push.c
index 8631c06..4ae9166 100644
--- a/builtin-push.c
+++ b/builtin-push.c
@@ -15,6 +15,7 @@ static const char * const push_usage[] = {
 };
 
 static int thin;
+static int deleterefs;
 static const char *receivepack;
 
 static const char **refspec;
@@ -44,6 +45,14 @@ static void set_refspecs(const char **refs, int nr)
 			strcat(tag, refs[i]);
 			ref = tag;
 		}
+		if (deleterefs && !strchr(ref, ':')) {
+			char *delref;
+			int len = strlen(refs[i] + 1);
+			delref = xmalloc(len);
+			strcpy(delref, ":");
+			strcat(delref, refs[i]);
+			ref = delref;
+		}
 		add_refspec(ref);
 	}
 }
@@ -181,6 +190,7 @@ int cmd_push(int argc, const char **argv, const char *prefix)
 		OPT_BIT( 0 , "all", &flags, "push all refs", TRANSPORT_PUSH_ALL),
 		OPT_BIT( 0 , "mirror", &flags, "mirror all refs",
 			    (TRANSPORT_PUSH_MIRROR|TRANSPORT_PUSH_FORCE)),
+		OPT_BOOLEAN( 0, "delete", &deleterefs, "delete refs"),
 		OPT_BOOLEAN( 0 , "tags", &tags, "push tags (can't be used with --all or --mirror)"),
 		OPT_BIT('n' , "dry-run", &flags, "dry run", TRANSPORT_PUSH_DRY_RUN),
 		OPT_BIT( 0,  "porcelain", &flags, "machine-readable output", TRANSPORT_PUSH_PORCELAIN),
@@ -193,6 +203,11 @@ int cmd_push(int argc, const char **argv, const char *prefix)
 
 	argc = parse_options(argc, argv, prefix, options, push_usage, 0);
 
+	if (deleterefs && (tags || (flags & (TRANSPORT_PUSH_ALL | TRANSPORT_PUSH_MIRROR))))
+		die("--delete is incompatible with --all, --mirror and --tags");
+	if (deleterefs && argc < 2)
+		die("--delete doesn't make sense without any refs");
+
 	if (tags)
 		add_refspec("refs/tags/*");
 
diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
index 6889a53..aa1450a 100755
--- a/t/t5516-fetch-push.sh
+++ b/t/t5516-fetch-push.sh
@@ -546,6 +546,12 @@ test_expect_success 'allow deleting an invalid remote ref' '
 
 '
 
+test_expect_success 'allow deleting a ref using --delete' '
+	mk_test heads/master &&
+	git push testrepo --delete master &&
+	(cd testrepo && test_must_fail git rev-parse --verify refs/heads/master)
+'
+
 test_expect_success 'warn on push to HEAD of non-bare repository' '
 	mk_test heads/master
 	(cd testrepo &&
-- 
1.6.5.2.155.gbb47.dirty