From ac2fc9c2a0e0d3eb32fd1c7f644eebe416e27597 Mon Sep 17 00:00:00 2001
From: "James R. Barlow" <jim@purplerock.ca>
Date: Sun, 19 May 2019 15:06:47 -0700
Subject: [PATCH] Explain picklable logger

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

diff --git a/src/ocrmypdf/_jobcontext.py b/src/ocrmypdf/_jobcontext.py
index cc23de85..5daab103 100644
--- a/src/ocrmypdf/_jobcontext.py
+++ b/src/ocrmypdf/_jobcontext.py
@@ -33,10 +33,11 @@ class PicklableLoggerMixin:
         return self._log
 
     def __getstate__(self):
-        log = self._log
-        self._log = None
-        state = self.__dict__
-        self._log = log
+        # Python 3.6 is incapable of pickling a logger and marshalling it to another
+        # process (threading._RLock error), so we disconnect it before pickling,
+        # and create a new logger in the worker process.
+        state = self.__dict__.copy()
+        state['_log'] = None
         return state