Bump libgit2 to more recent version

ext/rugged/rugged_reference.c

@@ -168,6 +168,22 @@ static VALUE rb_git_ref_exist(VALUE klass, VALUE rb_repo, VALUE rb_name)
 	return Qtrue;
 }
 
+/*
+ * call-seq:
+ *   Reference.valid?(name) -> true or false
+ *
+ * Checks whether the given string is a well-formed reference
+ * name. Note this just checks the syntax, no semantic checks
+ * are performed.
+ */
+static VALUE rb_git_ref_valid(VALUE self, VALUE rb_str)
+{
+  if (git_reference_is_valid_name(StringValueCStr(rb_str)))
+    return Qtrue;
+  else
+    return Qfalse;
+}
+
 /*
  *	call-seq:
  *		Reference.create(repository, name, oid, force = false) -> new_ref
@@ -561,6 +577,7 @@ void Init_rugged_reference()
 	rb_define_singleton_method(rb_cRuggedReference, "lookup", rb_git_ref_lookup, 2);
 	rb_define_singleton_method(rb_cRuggedReference, "exist?", rb_git_ref_exist, 2);
 	rb_define_singleton_method(rb_cRuggedReference, "exists?", rb_git_ref_exist, 2);
+  rb_define_singleton_method(rb_cRuggedReference, "valid?", rb_git_ref_valid, 1);
 	rb_define_singleton_method(rb_cRuggedReference, "create", rb_git_ref_create, -1);
 	rb_define_singleton_method(rb_cRuggedReference, "pack_all", rb_git_ref_packall, 1);
 	rb_define_singleton_method(rb_cRuggedReference, "each", rb_git_ref_each, -1);

ext/rugged/rugged_revwalk.c

@@ -106,7 +106,7 @@ static VALUE rb_git_walker_each(VALUE self)
 		rb_yield(rugged_object_new(rugged_owner(self), (git_object *)commit));
 	}
 
-	if (error != GIT_REVWALKOVER)
+	if (error != GIT_ITEROVER)
 		rugged_exception_check(error);
 
 	return Qnil;

lib/rugged/repository.rb

@@ -140,7 +140,8 @@ def create_branch(name, sha_or_ref = "HEAD")
       when Rugged::Object
         target = sha_or_ref.oid
       else
-        if (ref = Rugged::Reference.lookup(self, sha_or_ref))
+        if Rugged::Reference.valid?(sha_or_ref)
+          ref = Rugged::Reference.lookup(self, sha_or_ref)
           target = ref.resolve.target
         else
           target = Rugged::Commit.lookup(self, sha_or_ref)

test/reference_test.rb

@@ -65,6 +65,13 @@
     assert !exists
   end
 
+  test "recognises valid/invalid reference names" do
+    assert Rugged::Reference.valid?("refs/heads/master")
+    assert Rugged::Reference.valid?("HEAD")
+    assert Rugged::Reference.valid?("refs/heads/n0n3x15t4nt") # Only syntax check
+    assert !Rugged::Reference.valid?("5b5b025afb0b4c913b4c338a42934a3863bf3644") # Commits are no valid reference *names*
+  end
+
   test "can open packed reference" do
     ref = Rugged::Reference.lookup(@repo, "refs/heads/packed")
     assert_equal "41bc8c69075bbdb46c5c6f0566cc8cc5b46e8bd9", ref.target