Changes:

- docs and tests for cages
- add use_wrapper_for_read
- rename parameter self_register to skip_self_register and invert

docs/cages.md

@@ -1,11 +1,14 @@
 # Cages
 
-Cages are a way to manage global states in an non-global maner.
+Cages are transparent context variables. It forwards all function calls to the wrapped object so it behaves
+normal in most cases like the original despite all operations are executed on the contextvar clone of the original.
+The original is copied via copy or optionally via deepcopy.
 
+This allows monkey patching other libraries which are not async safe. Even from other libraries,
 
 ## Usage
 
-There are two methods
+There are two ways
 
 1. registering via self registering (recommended)
 2. registering manually
@@ -14,3 +17,61 @@ The first way is recommended because it can be detected if it would nest another
 In this case it would just skip the initialization and the old Cage is kept.
 
 Advantage of this: multiple libraries can patch other libraries without fearing to overwrite another cage.
+
+``` python
+from monkay import Cage
+
+foo = []
+foo2: list
+
+# we can move an existing variable in a cage
+Cage(globals(), name="foo", update_fn=lambda overwrite, new_original: new_original+overwrite)
+# we can inject
+Cage(globals(), [], name="foo2")
+# we can manually assign
+original: list = []
+cage_for_original = Cage(globals(), name="original", skip_self_register=True)
+
+foo.add("a")
+foo.add("b")
+assert foo == ["a", "b"]
+
+with foo.monkay_with_override(["b", "c"]):
+    assert foo == ["b", "c"]
+assert foo == ["a", "b"]
+
+with foo.monkay_with_original() as original:
+    assert original == []
+    original.append("updated")
+
+# thanks to the update function
+assert foo == ["updated", "a", "b"]
+```
+
+### With thread Lock
+
+Cages are async safe designed. They can even protect updates of the original via locks.
+With `use_wrapper_for_reads=True` inconsistent states for non-async safe copyable structures are prevented.
+
+``` python
+from threading import Lock
+from monkay import Cage
+
+foo: list
+Cage(globals(), [], name="foo", original_wrapper=Lock(), use_wrapper_for_reads=True, update_fn=lambda overwrite, new_original: new_original+overwrite)
+
+# now threadsafe
+with foo.monkay_with_original() as original:
+    assert original == []
+    original.append("updated")
+```
+
+### Preloads
+
+Of course cages support also preloads. See [Tutorial](./tutorial.md) for examples and the syntax.
+
+
+### Using deep copy
+
+By default when no contextvariable was initialized the original is copied via `copy.copy()` into the contextvariable.
+By providing `deep_copy=True` `copy.deepcopy()` is used.

docs/settings.md

@@ -1,6 +1,5 @@
 # Settings
 
-
 ## Setting settings forward
 
 Sometimes you have some packages which should work independently but
@@ -22,7 +21,6 @@ monkay = Monkay(
     globals(),
     settings_path=os.environ.get("MONKAY_CHILD_SETTINGS", "foo.test:example") or ""
 )
-
 ```
 
 Main
@@ -36,10 +34,8 @@ monkay = Monkay(
     settings_path=os.environ.get("MONKAY_MAIN_SETTINGS", "foo.test:example") or ""
 )
 child.monkay.settings = lambda: monkay.settings
-
 ```
 
-
 ## Lazy settings setup
 
 Like when using a settings forward it is possible to activate the settings later by assigning a string, a class or an settings instance
@@ -86,8 +82,6 @@ attribute and are cached.
 Functions get evaluated on every access and should care for caching in case it is required (for forwards the caching
 takes place in the main settings).
 
-
-
 ## Forwarder
 
 Sometimes you have an old settings place and want to forward it to the monkay one.

monkay/cages.py

@@ -22,6 +22,7 @@ class Undefined: ...
 class Cage(Generic[T]):
     monkay_context_var: ContextVar[tuple[int, T] | type[Undefined]]
     monkay_deep_copy: bool
+    monkay_use_wrapper_for_reads: bool
     monkay_update_fn: Callable[[T, T], T] | None
     monkay_original: T
     monkay_original_last_update: int
@@ -40,7 +41,8 @@ def __new__(
         # for e.g. locks
         original_wrapper: AbstractContextManager = nullcontext(),
         update_fn: Callable[[T, T], T] | None = None,
-        self_register: bool = True,
+        use_wrapper_for_reads: bool = False,
+        skip_self_register: bool = False,
         package: str | None = "",
     ) -> Cage:
         if package == "" and globals_dict.get("__spec__"):
@@ -57,7 +59,7 @@ def __new__(
         if obj is Undefined:
             obj = globals_dict[name]
         assert obj is not Undefined
-        if self_register and isinstance(obj, Cage):
+        if not skip_self_register and isinstance(obj, Cage):
             return obj
         context_var_name = context_var_name.format(name=name)
         obj_type = type(obj)
@@ -76,6 +78,7 @@ def __new__(
             context_var_name, default=Undefined
         )
         monkay_cage_instance.monkay_deep_copy = deep_copy
+        monkay_cage_instance.monkay_use_wrapper_for_reads = use_wrapper_for_reads
         monkay_cage_instance.monkay_update_fn = update_fn
         monkay_cage_instance.monkay_original = obj
         monkay_cage_instance.monkay_original_last_update = 0
@@ -84,7 +87,7 @@ def __new__(
         )
         monkay_cage_instance.monkay_original_wrapper = original_wrapper
 
-        if self_register:
+        if not skip_self_register:
             globals_dict[name] = monkay_cage_instance
         return monkay_cage_instance
 
@@ -99,14 +102,20 @@ def _(self, *args: Any, **kwargs: Any):
     def monkay_refresh_copy(
         self, *, obj: T | type[Undefined] = Undefined, _monkay_dict: dict | None = None
     ) -> T:
+        """Sets the contextvar."""
         if _monkay_dict is None:
             _monkay_dict = super().__getattribute__("__dict__")
         if obj is Undefined:
-            obj = (
-                copy.deepcopy(_monkay_dict["monkay_original"])
-                if _monkay_dict["monkay_deep_copy"]
-                else copy.copy(_monkay_dict["monkay_original"])
-            )
+            with (
+                _monkay_dict["monkay_original_wrapper"]
+                if _monkay_dict["monkay_use_wrapper_for_reads"]
+                else nullcontext()
+            ):
+                obj = (
+                    copy.deepcopy(_monkay_dict["monkay_original"])
+                    if _monkay_dict["monkay_deep_copy"]
+                    else copy.copy(_monkay_dict["monkay_original"])
+                )
         _monkay_dict["monkay_context_var"].set((_monkay_dict["monkay_original_last_update"], obj))
         return cast(T, obj)
 
@@ -120,7 +129,12 @@ def monkay_conditional_update_copy(self, *, _monkay_dict: dict | None = None) ->
             _monkay_dict["monkay_update_fn"] is not None
             and tup[0] != _monkay_dict["monkay_original_last_update"]
         ):
-            obj = _monkay_dict["monkay_update_fn"](obj, _monkay_dict["monkay_original"])
+            with (
+                _monkay_dict["monkay_original_wrapper"]
+                if _monkay_dict["monkay_use_wrapper_for_reads"]
+                else nullcontext()
+            ):
+                obj = _monkay_dict["monkay_update_fn"](tup[1], _monkay_dict["monkay_original"])
             obj = self.monkay_refresh_copy(obj=obj, _monkay_dict=_monkay_dict)
         else:
             obj = tup[1]

tests/targets/cages_preloaded.py

@@ -0,0 +1,2 @@
+def load():
+    from . import cages_preloaded_fn  # noqa

tests/test_cages.py

@@ -1,6 +1,7 @@
 import sys
 from contextvars import ContextVar
 from pathlib import Path
+from threading import Lock
 
 import pytest
 
@@ -32,17 +33,20 @@ def test_cages_overwrite():
 def test_cages_preload_and_register():
     d = {}
     assert "tests.targets.module_prefixed" not in sys.modules
-    assert "tests.targets.module_full_preloaded1" not in sys.modules
-    assert "tests.targets.module_full_preloaded1_fn" not in sys.modules
+    assert "tests.targets.cages_preloaded" not in sys.modules
+    assert "tests.targets.cages_preloaded_fn" not in sys.modules
     cage = Cage(
         d,
         target_ro,
         name="target_ro",
-        preloads=["tests.targets.module_prefixed", "tests.targets.module_full_preloaded1:load"],
+        preloads=[
+            "tests.targets.module_prefixed",
+            "tests.targets.cages_preloaded:load",
+        ],
     )
     assert "tests.targets.module_prefixed" in sys.modules
-    assert "tests.targets.module_full_preloaded1" in sys.modules
-    assert "tests.targets.module_full_preloaded1_fn" in sys.modules
+    assert "tests.targets.cages_preloaded" in sys.modules
+    assert "tests.targets.cages_preloaded_fn" in sys.modules
     assert isinstance(d["target_ro"], Cage)
     assert d["target_ro"] is cage
     assert isinstance(d["_target_ro_ctx"], ContextVar)
@@ -61,7 +65,38 @@ def test_cages_retrieve_with_name():
         globals(),
         name="target_ro",
         context_var_name="foo_cages_retrieve_with_name_ctx",
-        self_register=False,
+        skip_self_register=True,
     )
     assert type(globals()["target_ro"]) is not Cage
     assert isinstance(globals()["foo_cages_retrieve_with_name_ctx"], ContextVar)
+
+
+@pytest.mark.parametrize("read_lock", [True, False])
+def test_cages_wrapper_for_non_existing(read_lock):
+    lock = Lock()
+
+    def update_fn(context_content, original):
+        assert lock.locked() == read_lock
+        return original + context_content
+
+    cage = Cage(
+        globals(),
+        [],
+        name="target_cages_wrapper",
+        context_var_name=f"foo_cages_wrapper_ctx{read_lock}",
+        skip_self_register=True,
+        original_wrapper=lock,
+        use_wrapper_for_reads=read_lock,
+        update_fn=update_fn,
+    )
+    assert type(globals()["target_ro"]) is not Cage
+    assert isinstance(globals()[f"foo_cages_wrapper_ctx{read_lock}"], ContextVar)
+    assert cage == []
+    cage.append("b")
+    assert cage == ["b"]
+
+    with cage.monkay_with_original() as original:
+        original.append("a")
+    assert cage == ["a", "b"]
+    cage.append("c")
+    assert cage == ["a", "b", "c"]