--- a/hgext/remotefilelog/contentstore.py	Mon Apr 19 20:38:52 2021 -0400
+++ b/hgext/remotefilelog/contentstore.py	Mon Mar 29 01:52:06 2021 +0200
@@ -2,7 +2,10 @@
 
 import threading
 
-from mercurial.node import hex, nullid
+from mercurial.node import (
+    hex,
+    sha1nodeconstants,
+)
 from mercurial.pycompat import getattr
 from mercurial import (
     mdiff,
@@ -55,7 +58,7 @@
         """
         chain = self.getdeltachain(name, node)
 
-        if chain[-1][ChainIndicies.BASENODE] != nullid:
+        if chain[-1][ChainIndicies.BASENODE] != sha1nodeconstants.nullid:
             # If we didn't receive a full chain, throw
             raise KeyError((name, hex(node)))
 
@@ -92,7 +95,7 @@
         deltabasenode.
         """
         chain = self._getpartialchain(name, node)
-        while chain[-1][ChainIndicies.BASENODE] != nullid:
+        while chain[-1][ChainIndicies.BASENODE] != sha1nodeconstants.nullid:
             x, x, deltabasename, deltabasenode, x = chain[-1]
             try:
                 morechain = self._getpartialchain(deltabasename, deltabasenode)
@@ -187,7 +190,12 @@
         # Since remotefilelog content stores only contain full texts, just
         # return that.
         revision = self.get(name, node)
-        return revision, name, nullid, self.getmeta(name, node)
+        return (
+            revision,
+            name,
+            sha1nodeconstants.nullid,
+            self.getmeta(name, node),
+        )
 
     def getdeltachain(self, name, node):
         # Since remotefilelog content stores just contain full texts, we return
@@ -195,7 +203,7 @@
         # The nullid in the deltabasenode slot indicates that the revision is a
         # fulltext.
         revision = self.get(name, node)
-        return [(name, node, None, nullid, revision)]
+        return [(name, node, None, sha1nodeconstants.nullid, revision)]
 
     def getmeta(self, name, node):
         self._sanitizemetacache()
@@ -237,7 +245,12 @@
 
     def getdelta(self, name, node):
         revision = self.get(name, node)
-        return revision, name, nullid, self._shared.getmeta(name, node)
+        return (
+            revision,
+            name,
+            sha1nodeconstants.nullid,
+            self._shared.getmeta(name, node),
+        )
 
     def getdeltachain(self, name, node):
         # Since our remote content stores just contain full texts, we return a
@@ -245,7 +258,7 @@
         # The nullid in the deltabasenode slot indicates that the revision is a
         # fulltext.
         revision = self.get(name, node)
-        return [(name, node, None, nullid, revision)]
+        return [(name, node, None, sha1nodeconstants.nullid, revision)]
 
     def getmeta(self, name, node):
         self._fileservice.prefetch(
@@ -276,11 +289,11 @@
 
     def getdelta(self, name, node):
         revision = self.get(name, node)
-        return revision, name, nullid, self.getmeta(name, node)
+        return revision, name, self._cl.nullid, self.getmeta(name, node)
 
     def getdeltachain(self, name, node):
         revision = self.get(name, node)
-        return [(name, node, None, nullid, revision)]
+        return [(name, node, None, self._cl.nullid, revision)]
 
     def getmeta(self, name, node):
         rl = self._revlog(name)
@@ -304,9 +317,9 @@
             missing.discard(ancnode)
 
             p1, p2 = rl.parents(ancnode)
-            if p1 != nullid and p1 not in known:
+            if p1 != self._cl.nullid and p1 not in known:
                 missing.add(p1)
-            if p2 != nullid and p2 not in known:
+            if p2 != self._cl.nullid and p2 not in known:
                 missing.add(p2)
 
             linknode = self._cl.node(rl.linkrev(ancrev))