Stricten handlers' defaults, require values/Nones explicitly

In order to not get caught in a situation when an arg is forgotten,
which can cause misbehaviour or errors. The handlers are hidden
from the users, so we have no need to keep their interfaces simple.

kopf/on.py

@@ -146,7 +146,8 @@ def decorator(fn: callbacks.ResourceHandlerFn) -> callbacks.ResourceHandlerFn:
             fn=fn, id=real_id, field=None,
             errors=errors, timeout=timeout, retries=retries, backoff=backoff, cooldown=cooldown,
             labels=labels, annotations=annotations, when=when,
-            reason=None, initial=True, deleted=deleted,
+            initial=True, deleted=deleted, requires_finalizer=None,
+            reason=None,
         )
         real_registry.resource_changing_handlers[real_resource].append(handler)
         return fn
@@ -176,6 +177,7 @@ def decorator(fn: callbacks.ResourceHandlerFn) -> callbacks.ResourceHandlerFn:
             fn=fn, id=real_id, field=None,
             errors=errors, timeout=timeout, retries=retries, backoff=backoff, cooldown=cooldown,
             labels=labels, annotations=annotations, when=when,
+            initial=None, deleted=None, requires_finalizer=None,
             reason=causation.Reason.CREATE,
         )
         real_registry.resource_changing_handlers[real_resource].append(handler)
@@ -206,6 +208,7 @@ def decorator(fn: callbacks.ResourceHandlerFn) -> callbacks.ResourceHandlerFn:
             fn=fn, id=real_id, field=None,
             errors=errors, timeout=timeout, retries=retries, backoff=backoff, cooldown=cooldown,
             labels=labels, annotations=annotations, when=when,
+            initial=None, deleted=None, requires_finalizer=None,
             reason=causation.Reason.UPDATE,
         )
         real_registry.resource_changing_handlers[real_resource].append(handler)
@@ -237,8 +240,8 @@ def decorator(fn: callbacks.ResourceHandlerFn) -> callbacks.ResourceHandlerFn:
             fn=fn, id=real_id, field=None,
             errors=errors, timeout=timeout, retries=retries, backoff=backoff, cooldown=cooldown,
             labels=labels, annotations=annotations, when=when,
+            initial=None, deleted=None, requires_finalizer=bool(not optional),
             reason=causation.Reason.DELETE,
-            requires_finalizer=bool(not optional),
         )
         real_registry.resource_changing_handlers[real_resource].append(handler)
         return fn
@@ -270,6 +273,7 @@ def decorator(fn: callbacks.ResourceHandlerFn) -> callbacks.ResourceHandlerFn:
             fn=fn, id=real_id, field=real_field,
             errors=errors, timeout=timeout, retries=retries, backoff=backoff, cooldown=cooldown,
             labels=labels, annotations=annotations, when=when,
+            initial=None, deleted=None, requires_finalizer=None,
             reason=None,
         )
         real_registry.resource_changing_handlers[real_resource].append(handler)
@@ -295,6 +299,7 @@ def decorator(fn: callbacks.ResourceHandlerFn) -> callbacks.ResourceHandlerFn:
             fn=fn, id=real_id, field=None,
             errors=None, timeout=None, retries=None, backoff=None, cooldown=None,
             labels=labels, annotations=annotations, when=when,
+            initial=None, deleted=None, requires_finalizer=None,
             reason=None,
         )
         real_registry.resource_watching_handlers[real_resource].append(handler)
@@ -355,6 +360,7 @@ def decorator(fn: callbacks.ResourceHandlerFn) -> callbacks.ResourceHandlerFn:
             fn=fn, id=real_id, field=None,
             errors=errors, timeout=timeout, retries=retries, backoff=backoff, cooldown=cooldown,
             labels=labels, annotations=annotations, when=when,
+            initial=None, deleted=None, requires_finalizer=None,
             reason=None,
         )
         real_registry.append(handler)

kopf/reactor/handlers.py

@@ -46,7 +46,7 @@ def __getattribute__(self, name: str) -> Any:
 @dataclasses.dataclass
 class ActivityHandler(BaseHandler):
     fn: callbacks.ActivityHandlerFn  # type clarification
-    activity: Optional[causation.Activity] = None
+    activity: Optional[causation.Activity]
     _fallback: bool = False  # non-public!
 
 
@@ -55,12 +55,12 @@ class ResourceHandler(BaseHandler):
     fn: callbacks.ResourceHandlerFn  # type clarification
     reason: Optional[causation.Reason]
     field: Optional[dicts.FieldPath]
-    initial: Optional[bool] = None
-    deleted: Optional[bool] = None  # used for mixed-in (initial==True) @on.resume handlers only.
-    labels: Optional[bodies.Labels] = None
-    annotations: Optional[bodies.Annotations] = None
-    when: Optional[callbacks.WhenHandlerFn] = None
-    requires_finalizer: Optional[bool] = None
+    initial: Optional[bool]
+    deleted: Optional[bool]  # used for mixed-in (initial==True) @on.resume handlers only.
+    labels: Optional[bodies.Labels]
+    annotations: Optional[bodies.Annotations]
+    when: Optional[callbacks.WhenHandlerFn]
+    requires_finalizer: Optional[bool]
 
     @property
     def event(self) -> Optional[causation.Reason]:

kopf/reactor/handling.py

@@ -110,6 +110,8 @@ async def execute(
             handler = handlers_.ResourceHandler(
                 fn=fn, id=real_id,
                 errors=None, timeout=None, retries=None, backoff=None, cooldown=None,
+                labels=None, annotations=None, when=None,
+                initial=None, deleted=None, requires_finalizer=None,
                 reason=None, field=None,
             )
             subregistry.append(handler)
@@ -121,6 +123,8 @@ async def execute(
             handler = handlers_.ResourceHandler(
                 fn=fn, id=real_id,
                 errors=None, timeout=None, retries=None, backoff=None, cooldown=None,
+                labels=None, annotations=None, when=None,
+                initial=None, deleted=None, requires_finalizer=None,
                 reason=None, field=None,
             )
             subregistry.append(handler)

tests/basic-structs/test_handlers.py

@@ -46,8 +46,10 @@ def test_resource_handler_with_all_args(mocker):
     retries = mocker.Mock()
     backoff = mocker.Mock()
     initial = mocker.Mock()
+    deleted = mocker.Mock()
     labels = mocker.Mock()
     annotations = mocker.Mock()
+    when = mocker.Mock()
     requires_finalizer = mocker.Mock()
     handler = ResourceHandler(
         fn=fn,
@@ -60,8 +62,10 @@ def test_resource_handler_with_all_args(mocker):
         backoff=backoff,
         cooldown=None,  # deprecated, but still required
         initial=initial,
+        deleted=deleted,
         labels=labels,
         annotations=annotations,
+        when=when,
         requires_finalizer=requires_finalizer,
     )
     assert handler.fn is fn
@@ -73,8 +77,10 @@ def test_resource_handler_with_all_args(mocker):
     assert handler.retries is retries
     assert handler.backoff is backoff
     assert handler.initial is initial
+    assert handler.deleted is deleted
     assert handler.labels is labels
     assert handler.annotations is annotations
+    assert handler.when is when
     assert handler.requires_finalizer is requires_finalizer
 
     with pytest.deprecated_call(match=r"use handler.reason"):

tests/basic-structs/test_handlers_deprecated_cooldown.py

@@ -47,8 +47,10 @@ def test_resource_handler_with_deprecated_cooldown_instead_of_backoff(mocker):
     retries = mocker.Mock()
     backoff = mocker.Mock()
     initial = mocker.Mock()
+    deleted = mocker.Mock()
     labels = mocker.Mock()
     annotations = mocker.Mock()
+    when = mocker.Mock()
     requires_finalizer = mocker.Mock()
 
     with pytest.deprecated_call(match=r"use backoff="):
@@ -63,8 +65,10 @@ def test_resource_handler_with_deprecated_cooldown_instead_of_backoff(mocker):
             backoff=None,
             cooldown=backoff,  # deprecated, but still required
             initial=initial,
+            deleted=deleted,
             labels=labels,
             annotations=annotations,
+            when=when,
             requires_finalizer=requires_finalizer,
         )
 
@@ -77,6 +81,8 @@ def test_resource_handler_with_deprecated_cooldown_instead_of_backoff(mocker):
     assert handler.retries is retries
     assert handler.backoff is backoff
     assert handler.initial is initial
+    assert handler.deleted is deleted
     assert handler.labels is labels
     assert handler.annotations is annotations
+    assert handler.when is when
     assert handler.requires_finalizer is requires_finalizer

tests/registries/conftest.py

@@ -50,5 +50,7 @@ def parent_fn(**_):
     return ResourceHandler(
         fn=parent_fn, id=HandlerId('parent_fn'),
         errors=None, retries=None, timeout=None, backoff=None, cooldown=None,
+        labels=None, annotations=None, when=None,
+        initial=None, deleted=None, requires_finalizer=None,
         reason=None, field=None,
     )