diff -r 9bd6854aab86 -r 73ab542565e0 mercurial/debugcommands.py
--- a/mercurial/debugcommands.py	Sun Jan 05 22:00:40 2025 -0500
+++ b/mercurial/debugcommands.py	Sun Jan 05 22:12:02 2025 -0500
@@ -277,9 +277,9 @@
                     if len(ps) > 1:
                         p2 = repo[ps[1]]
                         pa = p1.ancestor(p2)
-                        base, local, other = [
+                        base, local, other = (
                             x[fn].data() for x in (pa, p1, p2)
-                        ]
+                        )
                         m3 = simplemerge.Merge3Text(
                             base,
                             local,