fixup! Ensure Tags can be created in detached Head state

Author: nulltoken

LibGit2Sharp/Core/Ensure.cs

@@ -209,34 +209,21 @@ public static void ArgumentConformsTo<T>(T argumentValue, Func<T, bool> checker,
         }
 
         public static void GitObjectIsNotNull(GitObject gitObject, string identifier)
-        {
-            Func<string, LibGit2SharpException> exceptionBuilder;
-
-            if (string.Equals("HEAD", identifier, StringComparison.Ordinal))
-            {
-                exceptionBuilder = m => new UnbornBranchException(m);
-            }
-            else
-            {
-                exceptionBuilder = m => new LibGit2SharpException(m);
-            }
-
-            GitObjectIsNotNull(gitObject, identifier, exceptionBuilder);
-        }
-
-        public static void GitObjectIsNotNull(
-            GitObject gitObject,
-            string identifier,
-            Func<string, LibGit2SharpException> exceptionBuilder)
         {
             if (gitObject != null)
             {
                 return;
             }
 
-            throw exceptionBuilder(string.Format(CultureInfo.InvariantCulture,
-                                                     "No valid git object identified by '{0}' exists in the repository.",
-                                                     identifier));
+            if (string.Equals("HEAD", identifier, StringComparison.Ordinal))
+            {
+                throw new UnbornBranchException(
+                    "HEAD points at a branch that is yet to be created.");
+            }
+            
+            throw new LibGit2SharpException(string.Format(CultureInfo.InvariantCulture,
+                "No valid git object identified by '{0}' exists in the repository.",
+                identifier));
         }
     }
 }

LibGit2Sharp/RepositoryExtensions.cs

@@ -98,7 +98,7 @@ private static Commit RetrieveHeadCommit(IRepository repository)
         {
             Commit commit = repository.Head.Tip;
 
-            Ensure.GitObjectIsNotNull(commit, "HEAD", m => new UnbornBranchException(m));
+            Ensure.GitObjectIsNotNull(commit, "HEAD");
 
             return commit;
         }