[PATCH] Extend "checkout --track" DWIM to support more cases

[Alex Riesen <raa.lkml@gmail.com>]

The code handles additionally "refs/remotes/<something>/name",
"remotes/<something>/name", and "refs/<namespace>/name".
Test cases included.

Signed-off-by: Alex Riesen <raa.lkml@gmail.com>
---

Johannes has likable ideas :)

 builtin-checkout.c |   20 +++++++++++++++-----
 t/t7201-co.sh      |   23 ++++++++++++++++++++++-
 2 files changed, 37 insertions(+), 6 deletions(-)

diff --git a/builtin-checkout.c b/builtin-checkout.c
index e95eab9..20466e2 100644
--- a/builtin-checkout.c
+++ b/builtin-checkout.c
@@ -447,11 +447,21 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 		char *slash;
 		if (!argc || !strcmp(argv[0], "--"))
 			die ("--track needs a branch name");
-		slash = strchr(argv[0], '/');
-		if (slash && !prefixcmp(argv[0], "refs/"))
-			slash = strchr(slash + 1, '/');
-		if (slash && !prefixcmp(argv[0], "remotes/"))
-			slash = strchr(slash + 1, '/');
+		if (!prefixcmp(argv[0], "remotes/"))
+			/* skip the name of a remote */
+			slash = strchr(argv[0] + 8, '/');
+		else if (!prefixcmp(argv[0], "refs/")) {
+			/* skip namespaces, try use the names of their
+			 * branches, but for the target namespace
+			 * (heads) demand a new name. Also skip the
+			 * first element in "remotes" namespace */
+			const char *ns = argv[0] + 5;
+			slash = !prefixcmp(ns, "heads/") ? NULL:
+				!prefixcmp(ns, "remotes/") ?
+				strchr(ns + 8, '/'): strchr(ns, '/');
+		} else
+			/* otherwise - just skip the first element */
+			slash = strchr(argv[0], '/');
 		if (!slash || !slash[1])
 			die ("Missing branch name; try -b");
 		opts.new_branch = slash + 1;
diff --git a/t/t7201-co.sh b/t/t7201-co.sh
index 943dd57..1dff84d 100755
--- a/t/t7201-co.sh
+++ b/t/t7201-co.sh
@@ -340,9 +340,30 @@ test_expect_success \
 test_expect_success \
     'checkout with --track fakes a sensible -b <name>' '
     git update-ref refs/remotes/origin/koala/bear renamer &&
+    git update-ref refs/new/koala/bear renamer &&
+
     git checkout --track origin/koala/bear &&
     test "refs/heads/koala/bear" = "$(git symbolic-ref HEAD)" &&
-    test "$(git rev-parse HEAD)" = "$(git rev-parse renamer)"'
+    test "$(git rev-parse HEAD)" = "$(git rev-parse renamer)" &&
+
+    git checkout master && git branch -D koala/bear &&
+
+    git checkout --track refs/remotes/origin/koala/bear &&
+    test "refs/heads/koala/bear" = "$(git symbolic-ref HEAD)" &&
+    test "$(git rev-parse HEAD)" = "$(git rev-parse renamer)" &&
+
+    git checkout master && git branch -D koala/bear &&
+
+    git checkout --track remotes/origin/koala/bear &&
+    test "refs/heads/koala/bear" = "$(git symbolic-ref HEAD)" &&
+    test "$(git rev-parse HEAD)" = "$(git rev-parse renamer)" &&
+
+    git checkout master && git branch -D koala/bear &&
+
+    git checkout --track refs/new/koala/bear &&
+    test "refs/heads/koala/bear" = "$(git symbolic-ref HEAD)" &&
+    test "$(git rev-parse HEAD)" = "$(git rev-parse renamer)"
+'
 
 test_expect_success \
     'checkout with --track, but without -b, fails with too short tracked name' '
-- 
1.6.0.22.g09248