call evaluate_settings_once optionally when accessing settings

Note:

This is dangerous in multithreading environments so a good solution is
required

docs/release-notes.md

@@ -6,6 +6,7 @@
 ### Added
 
 - Add `evaluate_settings_once`.
+- Add parameter `evaluate_settings_once_on_access`.
 
 ### Changed
 

docs/settings.md

@@ -95,6 +95,11 @@ It is internally used by `evaluate_settings_once` and will also set the `setting
 Internally it is a property which sets the right flag. Either on the ContextVar or on the instance.
 It is resetted when assigning settings and initial False for `with_settings`.
 
+
+### `evaluate_settings_once_on_access` parameter
+
+You can also call
+
 ## Other settings types
 
 All of the assignment examples are also possible as settings_path parameter.

monkay/_monkay_settings.py

@@ -13,6 +13,7 @@
 
 class MonkaySettings(Generic[SETTINGS]):
     package: str | None
+    evaluate_settings_once_on_access: bool
     _settings_evaluated: bool = False
     settings_preloads_name: str
     settings_extensions_name: str
@@ -73,6 +74,8 @@ def settings(self) -> SETTINGS:
             raise RuntimeError(
                 "Settings are not set yet. Returned settings are None or settings_path is empty."
             )
+        if self.evaluate_settings_once_on_access:
+            self.evaluate_settings_once(on_conflict="keep")
         return settings
 
     @settings.setter

monkay/core.py

@@ -46,6 +46,7 @@ def __init__(
         settings_ctx_name: str = "monkay_settings_ctx",
         extensions_applied_ctx_name: str = "monkay_extensions_applied_ctx",
         skip_all_update: bool = False,
+        evaluate_settings_once_on_access: bool = False,
         skip_getattr_fixup: bool = False,
         evaluate_settings: bool = True,
         pre_add_lazy_import_hook: None | PRE_ADD_LAZY_IMPORT_HOOK = None,
@@ -64,6 +65,7 @@ def __init__(
         self.package = package or None
 
         self._cached_imports: dict[str, Any] = {}
+        self.evaluate_settings_once_on_access = evaluate_settings_once_on_access
         self.pre_add_lazy_import_hook = pre_add_lazy_import_hook
         self.post_add_lazy_import_hook = post_add_lazy_import_hook
         self.uncached_imports = set(uncached_imports)
@@ -132,6 +134,8 @@ def evaluate_settings(
         *,
         on_conflict: Literal["error", "keep", "replace"] = "keep",
     ) -> None:
+        # set flag early so extensions can use settings when using evaluate_settings_once_on_access
+        self.settings_evaluated = True
         preloads = None
         if self.settings_preloads_name:
             preloads = get_value_from_settings(self.settings, self.settings_preloads_name)
@@ -148,7 +152,6 @@ def evaluate_settings(
         if self.settings_extensions_name:
             for extension in get_value_from_settings(self.settings, self.settings_extensions_name):
                 self.add_extension(extension, use_overwrite=True, on_conflict=on_conflict)
-        self.settings_evaluated = True
 
     def evaluate_settings_once(
         self,

tests/test_settings.py

@@ -67,6 +67,28 @@ def test_settings_overwrite():
             assert mod.monkay.settings is not old_settings
 
 
+def test_settings_on_access():
+    import tests.targets.module_full as mod
+
+    assert mod.monkay.settings_evaluated
+    mod.monkay.evaluate_settings_once_on_access = True
+
+    old_settings = mod.monkay.settings
+    settings_path = mod.monkay._settings_definition
+    assert isinstance(settings_path, str)
+
+    assert "tests.targets.module_settings_preloaded" not in sys.modules
+    new_settings = old_settings.model_copy(
+        update={"preloads": ["tests.targets.module_settings_preloaded"]}
+    )
+    with mod.monkay.with_settings(new_settings) as yielded:
+        assert not mod.monkay.settings_evaluated
+        assert "tests.targets.module_settings_preloaded" not in sys.modules
+        # evaluates settings
+        assert mod.monkay.settings is yielded
+        assert "tests.targets.module_settings_preloaded" in sys.modules
+
+
 @pytest.mark.parametrize("transform", [lambda x: x, lambda x: x.model_dump()])
 @pytest.mark.parametrize("mode", ["error", "replace", "keep"])
 def test_settings_overwrite_evaluate_modes(mode, transform):