diff --git a/mercurial/rewriteutil.py b/mercurial/rewriteutil.py
--- a/mercurial/rewriteutil.py
+++ b/mercurial/rewriteutil.py
@@ -49,7 +49,7 @@
     return summary
 
 
-def precheck(repo, revs, action=b'rewrite'):
+def precheck(repo, revs, action=b'rewrite', successors=None):
     """check if revs can be rewritten
     action is used to control the error message.
 
@@ -85,6 +85,10 @@
             hint=hint,
         )
 
+    # Adding a prune marker (A, ()) to obsstore can't be diverging
+    if action == b'prune' and not successors:
+        return
+
     if not obsolete.isenabled(repo, obsolete.allowdivergenceopt):
         new_divergence = _find_new_divergence(repo, revs)
         if new_divergence: