diff -r 7e954b08d129 -r 599c696bb514 tests/artifacts/scripts/generate-churning-bundle.py
--- a/tests/artifacts/scripts/generate-churning-bundle.py	Wed Dec 04 10:21:23 2024 +0100
+++ b/tests/artifacts/scripts/generate-churning-bundle.py	Tue Dec 03 23:49:37 2024 +0100
@@ -117,7 +117,7 @@
                 print("generating commit #%d/%d" % (idx, NB_CHANGESET))
             if (idx % PERIOD_BRANCHING) == 0:
                 move_back = MOVE_BACK_MIN + (idx % MOVE_BACK_RANGE)
-                hg('update', ".~%d" % move_back)
+                hg('update', "max(0+.~%d)" % move_back)
             if (idx % PERIOD_MERGING) == 0:
                 hg('merge', 'min(head())')
             updatefile(FILENAME, idx)