--- a/hgext3rd/evolve/firstmergecache.py	Tue Aug 06 11:29:35 2019 +0200
+++ b/hgext3rd/evolve/firstmergecache.py	Tue Aug 06 11:30:45 2019 +0200
@@ -61,7 +61,7 @@
 
     def __init__(self):
         super(firstmergecache, self).__init__()
-        self._data = array.array('l')
+        self._data = array.array(r'l')
 
     def get(self, rev):
         if len(self._data) <= rev:
@@ -108,7 +108,7 @@
         Subclasses MUST overide this method to actually affect the cache data.
         """
         super(firstmergecache, self).clear()
-        self._data = array.array('l')
+        self._data = array.array(r'l')
 
     # crude version of a cache, to show the kind of information we have to store
 
@@ -117,7 +117,7 @@
         assert repo.filtername is None
 
         data = repo.cachevfs.tryread(self._filepath)
-        self._data = array.array('l')
+        self._data = array.array(r'l')
         if not data:
             self._cachekey = self.emptykey
         else: