backout: leverage cmdutil.check_incompatible_arguments()

Differential Revision: https://phab.mercurial-scm.org/D9216

mercurial/commands.py

@@ -769,11 +769,8 b' def backout(ui, repo, node=None, rev=Non'
 
 
 def _dobackout(ui, repo, node=None, rev=None, **opts):
+    cmdutil.check_incompatible_arguments(opts, 'no_commit', ['commit', 'merge'])
     opts = pycompat.byteskwargs(opts)
-    if opts.get(b'commit') and opts.get(b'no_commit'):
-        raise error.Abort(_(b"cannot use --commit with --no-commit"))
-    if opts.get(b'merge') and opts.get(b'no_commit'):
-        raise error.Abort(_(b"cannot use --merge with --no-commit"))
 
     if rev and node:
         raise error.Abort(_(b"please specify just one revision"))

tests/test-backout.t

@@ -804,5 +804,5 b' Test usage of `hg resolve` in case of co'
 --no-commit can't be used with --merge
 
   $ hg backout --merge --no-commit 2
-  abort: cannot use --merge with --no-commit
+  abort: cannot specify both --no-commit and --merge
   [255]