--- a/mercurial/branching/rev_cache.py	Tue Sep 24 00:16:23 2024 +0200
+++ b/mercurial/branching/rev_cache.py	Tue Sep 24 03:16:35 2024 +0200
@@ -28,7 +28,9 @@
 
 # Revision branch info cache
 
-_rbcversion = b'-v1'
+# The "V2" version use the same format as the "V1" but garantee it won't be
+# truncated, preventing SIGBUS when it is mmap-ed
+_rbcversion = b'-v2'
 _rbcnames = b'rbc-names' + _rbcversion
 _rbcrevs = b'rbc-revs' + _rbcversion
 # [4 byte hash prefix][4 byte branch name number with sign bit indicating open]