refspec: fix transforming nested stars

When we transform a refspec with a component containing a glob, then
we simply copy over the component until the next separator from
the matching ref. E.g. if we have a ref "refs/heads/foo/bar" and
a refspec "refs/heads/*/bar:refs/remotes/origin/*/bar", we:

1. Copy over everything until hitting the glob from the <dst>
   part: "refs/remotes/origin/".
2. Strip the common prefix of ref and <src> part until the glob,
   which is "refs/heads/". This leaves us with a ref of "foo/bar".
3. Copy from the ref until the next "/" separator, resulting in
   "refs/remotes/origin/foo".
4. Copy over the remaining part of the <dst> spec, which is
   "bar": "refs/remotes/origin/foo/bar".

This worked just fine in a world where globs in refspecs were
restricted such that a globbing component may only contain a
single "*", only. But this restriction has been lifted, so that a
glob component may be nested between other characters, causing
the above algorithm to fail. Most notably the third step, where
we copy until hitting the next "/" separator, might result in a
wrong transformation. Given e.g. a ref "refs/gbranchg/head" and a
refspec "refs/g*g/head:refs/remotes/origin/*", we'd also be
copying the "g" between "branch" and "/" and end up with the
wrong transformed ref "refs/remotes/origin/branchg".

Instead of copying until the next component separator, we should
copy until we hit the pattern after the "*". So in the above
example, we'd copy until hitting the string "g/head".

1 files changed, 5 insertions, 0 deletions

diff --git a/tests/network/refspecs.c b/tests/network/refspecs.c
index 9df0a764f..734759060 100644
--- a/tests/network/refspecs.c
+++ b/tests/network/refspecs.c
@@ -120,6 +120,11 @@ void test_network_refspecs__transform_loosened_star(void)
 	assert_valid_transform("refs/heads/branch-*/head:refs/remotes/origin/branch-*/head", "refs/heads/branch-a/head", "refs/remotes/origin/branch-a/head");
 }
 
+void test_network_refspecs__transform_nested_star(void)
+{
+	assert_valid_transform("refs/heads/x*x/for-linus:refs/remotes/mine/*", "refs/heads/xbranchx/for-linus", "refs/remotes/mine/branch");
+}
+
 void test_network_refspecs__no_dst(void)
 {
 	assert_valid_transform("refs/heads/master:", "refs/heads/master", "");