diff -r a1e4fa9330d8 -r 421c9b3f2f4e mercurial/commit.py
--- a/mercurial/commit.py	Thu Aug 01 11:43:10 2024 -0400
+++ b/mercurial/commit.py	Thu Aug 01 13:38:31 2024 +0100
@@ -214,15 +214,15 @@
             elif narrow_action == mergestate.CHANGE_ADDED:
                 files.mark_added(f)
                 added.append(f)
-                m[f] = m2[f]
+                fnode = m2[f]
                 flags = m2ctx.find(f)[1] or b''
-                m.setflag(f, flags)
+                m.set(f, fnode, flags)
             elif narrow_action == mergestate.CHANGE_MODIFIED:
                 files.mark_touched(f)
                 added.append(f)
-                m[f] = m2[f]
+                fnode = m2[f]
                 flags = m2ctx.find(f)[1] or b''
-                m.setflag(f, flags)
+                m.set(f, fnode, flags)
             else:
                 msg = _(b"corrupted mergestate, unknown narrow action: %b")
                 hint = _(b"restart the merge")
@@ -234,7 +234,7 @@
                 removed.append(f)
             else:
                 added.append(f)
-                m[f], is_touched = _filecommit(
+                fnode, is_touched = _filecommit(
                     repo, fctx, m1, m2, linkrev, tr, writefilecopymeta, ms
                 )
                 if is_touched:
@@ -244,7 +244,7 @@
                         files.mark_merged(f)
                     else:
                         files.mark_touched(f)
-                m.setflag(f, fctx.flags())
+                m.set(f, fnode, fctx.flags())
         except OSError:
             repo.ui.warn(_(b"trouble committing %s!\n") % uipathfn(f))
             raise