From 41f58b69d81ab19ecd6ce307729d56ae873fdcf9 Mon Sep 17 00:00:00 2001
From: Ryan Fitzpatrick <rfitzpat@redhat.com>
Date: Wed, 6 Dec 2017 16:52:11 -0500
Subject: [PATCH] Avoid calling None in call_historic

---
 pluggy/__init__.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/pluggy/__init__.py b/pluggy/__init__.py
index 42d2220b..fa012905 100644
--- a/pluggy/__init__.py
+++ b/pluggy/__init__.py
@@ -626,6 +626,8 @@ def call_historic(self, proc=None, kwargs=None):
         self._call_history.append((kwargs or {}, proc))
         # historizing hooks don't return results
         res = self._hookexec(self, self._nonwrappers + self._wrappers, kwargs)
+        if proc is None:
+            return
         for x in res or []:
             proc(x)