diff -r 56d441256e82 -r 5a0b930cfb3e mercurial/commit.py
--- a/mercurial/commit.py	Wed Mar 17 20:06:35 2021 +0100
+++ b/mercurial/commit.py	Wed Mar 10 13:14:32 2021 +0530
@@ -361,6 +361,8 @@
     elif fparent2 != nullid:
         if ms.active() and ms.extras(fname).get(b'filenode-source') == b'other':
             fparent1, fparent2 = fparent2, nullid
+        elif ms.active() and ms.extras(fname).get(b'merged') != b'yes':
+            fparent1, fparent2 = fparent1, nullid
         # is one parent an ancestor of the other?
         else:
             fparentancestors = flog.commonancestorsheads(fparent1, fparent2)