From e073ef08b9644308ca4a2e9757c27a19ff245a6b Mon Sep 17 00:00:00 2001
From: Damien Elmes <gpg@ankiweb.net>
Date: Tue, 5 Feb 2019 12:30:01 +1000
Subject: [PATCH] shift revlog eases when turning v2 sched on/off

fixes old 'good'/'easy' answers showing up as 'hard'/'good' in
the graphs
---
 anki/schedv2.py | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/anki/schedv2.py b/anki/schedv2.py
index d8ac04712..5bf4bb9b9 100644
--- a/anki/schedv2.py
+++ b/anki/schedv2.py
@@ -1617,13 +1617,20 @@ where queue < 0""" % (intTime(), self.col.usn()))
     def _moveManuallyBuried(self):
         self.col.db.execute("update cards set queue=-2,mod=%d where queue=-3" % intTime())
 
+    # adding 'hard' in v2 scheduler means old ease entries need shifting
+    # up or down
+    def _remapLearningAnswers(self, sql):
+        self.col.db.execute("update revlog set %s" % sql)
+
     def moveToV1(self):
         self._emptyAllFiltered()
         self._removeAllFromLearning()
 
         self._moveManuallyBuried()
         self._resetSuspendedLearning()
+        self._remapLearningAnswers("ease=ease-1 where ease in (3,4)")
 
     def moveToV2(self):
         self._emptyAllFiltered()
         self._removeAllFromLearning()
+        self._remapLearningAnswers("ease=ease+1 where ease in (2,3)")