From 166593e77ca7bbf21625f3625b8a0581dbda0db1 Mon Sep 17 00:00:00 2001
From: Allen Zhong <zhongzhw6@gmail.com>
Date: Thu, 28 Aug 2025 17:58:31 +1000
Subject: [PATCH] fix statistics collection for flattening

---
 src/minizinc/instance.py | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/minizinc/instance.py b/src/minizinc/instance.py
index 9d903b8..7f23c02 100644
--- a/src/minizinc/instance.py
+++ b/src/minizinc/instance.py
@@ -1000,10 +1000,11 @@ def flat(
             output = self._driver._run(cmd, solver=self._solver)
 
         statistics: Dict[str, Any] = {}
-        matches = re.findall(rb"%%%mzn-stat:? (\w*)=([^\r\n]*)", output.stdout)
-        for m in matches:
-            set_stat(statistics, m[0].decode(), m[1].decode())
-
+        for obj in decode_json_stream(output.stdout):
+            if obj["type"] == "statistics":
+                statistics = {k: v for k, v in obj["statistics"].items()}
+                break
+        
         try:
             yield fzn, ozn, statistics
         finally: