fix Flow.kill behaviour

This now just sets a kill reply instead of committing directly.
First, this seems like the more sane thing to do.
Second, we have an iffy race condition where we call Reply.commit()
before the addonmanager finishes its invocation, the proxy thread then progresses
and sets a new flow.reply attribute, and the addonmanager then gets confused
when finishing. This commit doesn't fix that, but mitigates it for Flow.kill
which is now committed by the addonmanager.

1 files changed, 4 insertions, 4 deletions

diff --git a/mitmproxy/controller.py b/mitmproxy/controller.py
index 63117ef0..f39c1b24 100644
--- a/mitmproxy/controller.py
+++ b/mitmproxy/controller.py
@@ -105,16 +105,16 @@ class Reply:
         self.q.put(self.value)
 
     def ack(self, force=False):
-        if self.state not in {"start", "taken"}:
-            raise exceptions.ControlException(
-                "Reply is {}, but expected it to be start or taken.".format(self.state)
-            )
         self.send(self.obj, force)
 
     def kill(self, force=False):
         self.send(exceptions.Kill, force)
 
     def send(self, msg, force=False):
+        if self.state not in {"start", "taken"}:
+            raise exceptions.ControlException(
+                "Reply is {}, but expected it to be start or taken.".format(self.state)
+            )
         if self.has_message and not force:
             raise exceptions.ControlException("There is already a reply message.")
         self.value = msg