Delegate detection of invalid reference names

Author: nulltoken

LibGit2Sharp/Core/NativeMethods.cs

@@ -489,6 +489,10 @@ internal static extern int git_reference_foreach_glob(
         [DllImport(libgit2)]
         internal static extern void git_reference_free(IntPtr reference);
 
+        [DllImport(libgit2)]
+        internal static extern int git_reference_is_valid_name(
+            [MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof(Utf8Marshaler))] string refname);
+
         [DllImport(libgit2)]
         internal static extern int git_reference_lookup(
             out ReferenceSafeHandle reference,

LibGit2Sharp/Core/Proxy.cs

@@ -883,6 +883,11 @@ public static void git_reference_free(IntPtr reference)
             NativeMethods.git_reference_free(reference);
         }
 
+        public static bool git_reference_is_valid_name(string refname)
+        {
+            return NativeMethods.git_reference_is_valid_name(refname) != 0;
+        }
+
         public static IList<string> git_reference_list(RepositorySafeHandle repo, GitReferenceType flags)
         {
             using (ThreadAffinity())

LibGit2Sharp/ReferenceCollectionExtensions.cs

@@ -19,25 +19,15 @@ private enum RefState
 
         private static RefState TryResolveReference(out Reference reference, ReferenceCollection refsColl, string canonicalName)
         {
-            try
-            {
-                //TODO: Maybe would it be better to rather rely on git_reference_normalize_name()
-                //This would be much more straightforward and less subject to fail for the wrong reason.
-
-                reference = refsColl[canonicalName];
-
-                if (reference != null)
-                {
-                    return RefState.Exists;
-                }
-
-                return RefState.DoesNotExistButLooksValid;
-            }
-            catch (LibGit2SharpException)
+            if (!Proxy.git_reference_is_valid_name(canonicalName))
             {
                 reference = null;
                 return RefState.DoesNotLookValid;
             }
+
+            reference = refsColl[canonicalName];
+
+            return reference != null ? RefState.Exists : RefState.DoesNotExistButLooksValid;
         }
 
         /// <summary>