Fixed the issue where field values containing spaces were being rejected with an unhelpful error message (#1665)

httpie/cli/argtypes.py

@@ -103,6 +103,13 @@ def __call__(self, s: str) -> KeyValueArg:
                 break
 
         else:
+            # Check if this looks like it should be a continuation of a previous value
+            # (i.e., it's a string without any separator, likely due to unquoted shell args)
+            if all(c not in s for c in self.special_characters):
+                raise argparse.ArgumentTypeError(
+                    f'{s!r} is not a valid value. Did you mean to quote it as part of a previous item? '
+                    f'For example: field="value {s}"'
+                )
             raise argparse.ArgumentTypeError(f'{s!r} is not a valid value')
 
         return self.key_value_class(key=key, value=value, sep=sep, orig=s)

tests/test_cli.py

@@ -27,6 +27,13 @@ def test_invalid_items(self):
         for item in items:
             pytest.raises(argparse.ArgumentTypeError, self.key_value_arg, item)
 
+    def test_invalid_item_without_separator_provides_helpful_error(self):
+        """Test that items without separators show a helpful error message."""
+        with pytest.raises(argparse.ArgumentTypeError) as exc_info:
+            self.key_value_arg('Bar')
+        assert 'Did you mean to quote it' in str(exc_info.value)
+        assert 'field="value Bar"' in str(exc_info.value)
+
     def test_escape_separator(self):
         items = RequestItems.from_args([
             # headers
@@ -63,6 +70,16 @@ def test_backslash_before_non_special_character_does_not_escape(
         actual = self.key_value_arg(string)
         assert actual == expected
 
+    @pytest.mark.parametrize('item_string, expected_value', [
+        ('field=value with spaces', 'value with spaces'),
+        ('field_name="Foo Bar"', '"Foo Bar"'),
+        ('data=Hello World Test', 'Hello World Test'),
+    ])
+    def test_values_with_spaces_when_properly_quoted(self, item_string, expected_value):
+        """Test that values with spaces work correctly when properly quoted."""
+        result = self.key_value_arg(item_string)
+        assert result.value == expected_value
+
     def test_escape_longsep(self):
         items = RequestItems.from_args([
             self.key_value_arg(r'bob\:==foo'),