# HG changeset patch
# User Pierre-Yves David <pierre-yves.david@octobus.net>
# Date 2022-07-26 08:48:06
# Node ID c6aac50038bb0abdb5a5302ec7985c3f8fef44b6
# Parent  ac4fda5d3ccda98ecc01de805bd4753ad08df8ee

debug-discovery: deal with case where common is empty

This code was previously confused by case where:

    `heads_common == {nullid}`

diff --git a/mercurial/debugcommands.py b/mercurial/debugcommands.py
--- a/mercurial/debugcommands.py
+++ b/mercurial/debugcommands.py
@@ -1330,6 +1330,8 @@ def debugdiscovery(ui, repo, remoteurl=b
             common, hds = doit(localrevs, remoterevs)
 
     # compute all statistics
+    if len(common) == 1 and repo.nullid in common:
+        common = set()
     heads_common = set(common)
     heads_remote = set(hds)
     heads_local = set(repo.heads())