From 2302a6baba755fdb259c58f2546b038ff2b81ea9 Mon Sep 17 00:00:00 2001
From: Kevin Hu <kevinhu.sh@gmail.com>
Date: Mon, 19 Aug 2024 09:24:03 +0800
Subject: [PATCH] fix empty mind map issue (#1991)

### What problem does this PR solve?

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)
---
 graphrag/mind_map_extractor.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/graphrag/mind_map_extractor.py b/graphrag/mind_map_extractor.py
index fabdaed08..652c871d6 100644
--- a/graphrag/mind_map_extractor.py
+++ b/graphrag/mind_map_extractor.py
@@ -105,6 +105,9 @@ class MindMapExtractor:
             for i, _ in enumerate(threads):
                 res.append(_.result())
 
+            if not res:
+                return MindMapResult(output={"root":{}})
+
             merge_json = reduce(self._merge, res)
             if len(merge_json.keys()) > 1:
                 keyset = set(