diff -r 204af2aa4931 -r d6e5bec550f1 mercurial/logcmdutil.py
--- a/mercurial/logcmdutil.py	Thu Sep 07 08:39:21 2023 +0200
+++ b/mercurial/logcmdutil.py	Wed Nov 15 02:39:53 2023 +0100
@@ -11,18 +11,18 @@
 import posixpath
 
 from .i18n import _
-from .node import nullrev, wdirrev
+from .node import wdirrev
 
 from .thirdparty import attr
 
 from . import (
     dagop,
+    diffutil,
     error,
     formatter,
     graphmod,
     match as matchmod,
     mdiff,
-    merge,
     patch,
     pathutil,
     pycompat,
@@ -69,35 +69,6 @@
     return limit
 
 
-def diff_parent(ctx):
-    """get the context object to use as parent when diffing
-
-
-    If diff.merge is enabled, an overlayworkingctx of the auto-merged parents will be returned.
-    """
-    repo = ctx.repo()
-    if repo.ui.configbool(b"diff", b"merge") and ctx.p2().rev() != nullrev:
-        # avoid cycle context -> subrepo -> cmdutil -> logcmdutil
-        from . import context
-
-        wctx = context.overlayworkingctx(repo)
-        wctx.setbase(ctx.p1())
-        with repo.ui.configoverride(
-            {
-                (
-                    b"ui",
-                    b"forcemerge",
-                ): b"internal:merge3-lie-about-conflicts",
-            },
-            b"merge-diff",
-        ):
-            with repo.ui.silent():
-                merge.merge(ctx.p2(), wc=wctx)
-        return wctx
-    else:
-        return ctx.p1()
-
-
 def get_diff_chunks(
     ui,
     repo,
@@ -273,7 +244,7 @@
             ui,
             ctx.repo(),
             diffopts,
-            diff_parent(ctx),
+            diffutil.diff_parent(ctx),
             ctx,
             match=self._makefilematcher(ctx),
             stat=stat,
@@ -286,7 +257,7 @@
             ui,
             ctx.repo(),
             diffopts,
-            diff_parent(ctx),
+            diffutil.diff_parent(ctx),
             ctx,
             match=self._makefilematcher(ctx),
             stat=stat,