Merge pull request #49 from seapagan/fix-none-values

Don't save `None` values to the TOML file.

TODO.md

@@ -9,4 +9,6 @@
   found then look in the users home directory.
 - Add an Option to not include the `schema_version` key. By default this key
   **will** be included.
-- Migrate to Ruff for linting and formatting
+- Allow a global config file to be used, which will be overridden by a local
+  config file if it exists.
+- option to not save config options that have the same value as the default.

docs/usage.md

@@ -90,6 +90,19 @@ settings = MySettings("my_app_name", settings_file_name="my_settings.toml")
 
 ## Using the settings
 
+!!! danger "`None` values"
+
+    The library does not support saving `None` values.  If you need to save a
+    `None` value, you should use a different value (such as an empty string or
+    `0`) and convert it to `None` in your app.
+
+    This is because TOML does not support `None` values and the library will
+    convert `None` values to `null` when saving the settings.
+
+    We may add support for this in the future, but for now you should avoid
+    using `None` values unless they are a default and will never need to be
+    saved - **any `None` value will not be saved to the config file**.
+
 Once you have created your settings class, you can use it like any other class:
 
 ```python

simple_toml_settings/settings.py

@@ -63,14 +63,19 @@ def __post_create_hook__(self) -> None:
         never be called manually.
         """
 
-    def get_attrs(self) -> dict[str, str]:
-        """Return a dictionary of our setting values."""
+    def get_attrs(self, *, include_none: bool = False) -> dict[str, str]:
+        """Return a dictionary of our setting values.
+
+        Values that are None are EXCLUDED by default, but can be included by
+        setting 'include_none' to True.
+        """
         return {
             a: getattr(self, a)
             for a in dir(self)
             if not a.startswith("_")
             and a not in self._ignored_attrs
             and not callable(getattr(self, a))
+            and (include_none or getattr(self, a) is not None)
         }
 
     def save(self) -> None:

tests/test_settings.py

@@ -56,13 +56,40 @@ def test_get_attrs(settings) -> None:
     assert attrs["test_int_var"] == SettingsExample.test_int_var
 
 
+def test_get_attrs_ignores_none_by_default(settings) -> None:
+    """Test that None attributes are not returned."""
+    settings.set("new_key", None)
+    attrs = settings.get_attrs()
+    assert "new_key" not in attrs
+
+
+def test_save_ignores_none_values(settings) -> None:
+    """Test that None attributes are not saved."""
+    settings.set("new_key", None)
+    settings.save()
+    attrs = settings.get_attrs()
+    assert "new_key" not in attrs
+
+
+def test_get_attrs_returns_none_if_include_none_true(settings) -> None:
+    """Test that None attributes are returned if required is True."""
+    settings.set("new_key", None)
+    attrs = settings.get_attrs(include_none=True)
+    assert attrs["new_key"] is None
+
+
 def test_get(settings) -> None:
     """Test we can get settings."""
     assert settings.get("app_name") == TEST_APP_NAME
     assert settings.get("test_string_var") == SettingsExample.test_string_var
     assert settings.get("test_int_var") == SettingsExample.test_int_var
 
 
+def test_get_missing_setting(settings) -> None:
+    """Test that 'None' is returned when a setting is missing."""
+    assert settings.get("missing_setting") is None
+
+
 def test_set(settings) -> None:
     """Test that a setting can be set."""
     settings.set("app_name", "new_test_app")
@@ -76,6 +103,12 @@ def test_add_and_list_setting(settings) -> None:
     assert settings_dict["new_key"] == "new_value"
 
 
+def test_add_none_value(settings) -> None:
+    """Test that a setting can be set to None."""
+    settings.set("new_key", None)
+    assert settings.get("new_key") is None
+
+
 def test_load_settings(settings) -> None:
     """Test that settings are loaded from the settings file."""
     settings.load()