diff -r fa159bb463e6 -r 5151b0f6519e mercurial/filemerge.py
--- a/mercurial/filemerge.py	Tue Dec 07 14:11:58 2021 -0800
+++ b/mercurial/filemerge.py	Tue Dec 07 17:48:50 2021 -0800
@@ -579,43 +579,24 @@
     )
 
 
-def _imergeauto(
-    repo,
-    mynode,
-    fcd,
-    fco,
-    fca,
-    toolconf,
-    backup,
-    labels=None,
-    localorother=None,
-):
-    """
-    Generic driver for _imergelocal and _imergeother
-    """
-    assert localorother is not None
-    r = simplemerge.simplemerge(
-        repo.ui, fcd, fca, fco, label=labels, localorother=localorother
-    )
-    return True, r
-
-
 @internaltool(b'merge-local', mergeonly, precheck=_mergecheck)
-def _imergelocal(*args, **kwargs):
+def _imergelocal(repo, mynode, fcd, fco, fca, toolconf, backup, labels=None):
     """
     Like :merge, but resolve all conflicts non-interactively in favor
     of the local `p1()` changes."""
-    success, status = _imergeauto(localorother=b'local', *args, **kwargs)
-    return success, status, False
+    return _merge(
+        repo, mynode, fcd, fco, fca, toolconf, backup, labels, b'local'
+    )
 
 
 @internaltool(b'merge-other', mergeonly, precheck=_mergecheck)
-def _imergeother(*args, **kwargs):
+def _imergeother(repo, mynode, fcd, fco, fca, toolconf, backup, labels=None):
     """
     Like :merge, but resolve all conflicts non-interactively in favor
     of the other `p2()` changes."""
-    success, status = _imergeauto(localorother=b'other', *args, **kwargs)
-    return success, status, False
+    return _merge(
+        repo, mynode, fcd, fco, fca, toolconf, backup, labels, b'other'
+    )
 
 
 @internaltool(