Report invalid --format-options as a CLI error, not a traceback

httpie/cli/argparser.py

@@ -555,7 +555,12 @@ def _process_format_options(self):
         format_options = self.args.format_options or []
         parsed_options = PARSED_DEFAULT_FORMAT_OPTIONS
         for options_group in format_options:
-            parsed_options = parse_format_options(options_group, defaults=parsed_options)
+            try:
+                parsed_options = parse_format_options(options_group, defaults=parsed_options)
+            except argparse.ArgumentTypeError as e:
+                if self.args.traceback:
+                    raise
+                self.error(f'--format-options: {e.args[0]}')
         self.args.format_options = parsed_options
 
     def print_manual(self):

tests/test_output.py

@@ -450,6 +450,35 @@ def test_parse_format_options_errors(self, options_string, expected_error):
         with pytest.raises(argparse.ArgumentTypeError, match=expected_error):
             parse_format_options(s=options_string, defaults=defaults)
 
+    @pytest.mark.parametrize(
+        'options_string, expected_error',
+        [
+            ('json', 'invalid option'),
+            ('json.nope:1', 'invalid key'),
+            ('json.indent:nope', "invalid value 'nope'"),
+        ]
+    )
+    def test_invalid_format_options_are_reported_as_cli_errors(
+        self, options_string, expected_error
+    ):
+        # An invalid --format-options value must produce a regular CLI error,
+        # not an unhandled `argparse.ArgumentTypeError` traceback.
+        r = unhandled = None
+        try:
+            r = http(
+                '--offline', f'--format-options={options_string}', DUMMY_URL,
+                tolerate_error_exit_status=True,
+            )
+        except Exception as exc:  # noqa: BLE001
+            unhandled = exc
+
+        assert unhandled is None, (
+            f'unhandled {type(unhandled).__name__}: {unhandled}'
+        )
+        assert r.exit_status == ExitStatus.ERROR
+        assert '--format-options' in r.stderr
+        assert expected_error in r.stderr
+
     @pytest.mark.parametrize(
         'args, expected_format_options',
         [