diff -r a78dfb1ad60e -r 024e0580b853 mercurial/diffutil.py
--- a/mercurial/diffutil.py	Mon Jan 09 14:34:19 2023 -0500
+++ b/mercurial/diffutil.py	Tue Jan 10 12:55:49 2023 -0500
@@ -120,7 +120,7 @@
         )
         buildopts[b'ignorewseol'] = get(b'ignore_space_at_eol', b'ignorewseol')
     if formatchanging:
-        buildopts[b'text'] = opts and opts.get(b'text')
+        buildopts[b'text'] = None if opts is None else opts.get(b'text')
         binary = None if opts is None else opts.get(b'binary')
         buildopts[b'nobinary'] = (
             not binary