fix #2529

2 files changed, 13 insertions, 2 deletions

diff --git a/mitmproxy/flow.py b/mitmproxy/flow.py
index dc778404..111566b8 100644
--- a/mitmproxy/flow.py
+++ b/mitmproxy/flow.py
@@ -179,5 +179,7 @@ class Flow(stateobject.StateObject):
         if not self.intercepted:
             return
         self.intercepted = False
-        self.reply.ack()
-        self.reply.commit()
+        # If a flow is intercepted and then duplicated, the duplicated one is not taken.
+        if self.reply.state == "taken":
+            self.reply.ack()
+            self.reply.commit()
diff --git a/test/mitmproxy/test_http.py b/test/mitmproxy/test_http.py
index 4463961a..49e61e25 100644
--- a/test/mitmproxy/test_http.py
+++ b/test/mitmproxy/test_http.py
@@ -203,6 +203,15 @@ class TestHTTPFlow:
         f.resume()
         assert f.reply.state == "committed"
 
+    def test_resume_duplicated(self):
+        f = tflow.tflow()
+        f.intercept()
+        f2 = f.copy()
+        assert f.intercepted is f2.intercepted is True
+        f.resume()
+        f2.resume()
+        assert f.intercepted is f2.intercepted is False
+
     def test_replace_unicode(self):
         f = tflow.tflow(resp=True)
         f.response.content = b"\xc2foo"