Fix current git commit hash detection when on a detached head

Author: LagoLunatic

randomizer.py

@@ -40,14 +40,18 @@
   git_commit_head_file = os.path.join(RANDO_ROOT_PATH, ".git", "HEAD")
   if os.path.isfile(git_commit_head_file):
     with open(git_commit_head_file, "r") as f:
-      head_file_contents = f.read()
+      head_file_contents = f.read().strip()
     if head_file_contents.startswith("ref: "):
-      relative_path_to_hash_file = head_file_contents[len("ref: "):].strip()
+      # Normal head, HEAD file has a reference to a branch which contains the commit hash
+      relative_path_to_hash_file = head_file_contents[len("ref: "):]
       path_to_hash_file = os.path.join(RANDO_ROOT_PATH, ".git", relative_path_to_hash_file)
       if os.path.isfile(path_to_hash_file):
         with open(path_to_hash_file, "r") as f:
           hash_file_contents = f.read()
         version_suffix = "_" + hash_file_contents[:7]
+    elif re.search(r"^[0-9a-f]{40}$", head_file_contents):
+      # Detached head, commit hash directly in the HEAD file
+      version_suffix = "_" + head_file_contents[:7]
 
   VERSION += version_suffix