diff --git a/mercurial/dirstate.py b/mercurial/dirstate.py
--- a/mercurial/dirstate.py
+++ b/mercurial/dirstate.py
@@ -103,6 +103,13 @@ class dirstate(object):
         # raises an exception).
         self._cwd
 
+    def prefetch_parents(self):
+        """make sure the parents are loaded
+
+        Used to avoid a race condition.
+        """
+        self._pl
+
     @contextlib.contextmanager
     def parentchange(self):
         '''Context manager for handling dirstate parents.
diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -1450,6 +1450,8 @@ class localrepository(object):
 
     @storecache(b'00changelog.i')
     def changelog(self):
+        # load dirstate before changelog to avoid race see issue6303
+        self.dirstate.prefetch_parents()
         return self.store.changelog(txnutil.mayhavepending(self.root))
 
     @storecache(b'00manifest.i')
diff --git a/tests/test-static-http.t b/tests/test-static-http.t
--- a/tests/test-static-http.t
+++ b/tests/test-static-http.t
@@ -233,6 +233,7 @@ List of files accessed over HTTP:
   /.hg/cache/hgtagsfnodes1
   /.hg/cache/rbc-names-v1
   /.hg/cache/rbc-revs-v1
+  /.hg/dirstate
   /.hg/requires
   /.hg/store/00changelog.i
   /.hg/store/00manifest.i
@@ -250,6 +251,7 @@ List of files accessed over HTTP:
   /remote-with-names/.hg/cache/rbc-names-v1
   /remote-with-names/.hg/cache/rbc-revs-v1
   /remote-with-names/.hg/cache/tags2-served
+  /remote-with-names/.hg/dirstate
   /remote-with-names/.hg/localtags
   /remote-with-names/.hg/requires
   /remote-with-names/.hg/store/00changelog.i
@@ -266,6 +268,7 @@ List of files accessed over HTTP:
   /remote/.hg/cache/rbc-names-v1
   /remote/.hg/cache/rbc-revs-v1
   /remote/.hg/cache/tags2-served
+  /remote/.hg/dirstate
   /remote/.hg/localtags
   /remote/.hg/requires
   /remote/.hg/store/00changelog.i
@@ -278,6 +281,7 @@ List of files accessed over HTTP:
   /remote/.hg/store/data/~2ehgtags.i (py37 !)
   /remotempty/.hg/bookmarks
   /remotempty/.hg/bookmarks.current
+  /remotempty/.hg/dirstate
   /remotempty/.hg/requires
   /remotempty/.hg/store/00changelog.i
   /remotempty/.hg/store/00manifest.i
@@ -286,6 +290,7 @@ List of files accessed over HTTP:
   /sub/.hg/cache/hgtagsfnodes1
   /sub/.hg/cache/rbc-names-v1
   /sub/.hg/cache/rbc-revs-v1
+  /sub/.hg/dirstate
   /sub/.hg/requires
   /sub/.hg/store/00changelog.i
   /sub/.hg/store/00manifest.i