Fix on-field handler selection when a field is longer/equal to a diff

kopf/reactor/registries.py

@@ -621,7 +621,9 @@ def _matches_field(
  return (ignore_fields or
  not isinstance(handler, handlers.ResourceChangingHandler) or
  not handler.field or
- any(field[:len(handler.field)] == handler.field for field in changed_fields))
+ any(changed_field[:len(handler.field)] == handler.field or # a.b.c -vs- a.b => ignore c
+ changed_field == handler.field[:len(changed_field)] # a.b -vs- a.b.c => ignore c
+ for changed_field in changed_fields))
 
 
 def _matches_labels(

tests/registries/test_handler_matching.py

@@ -7,6 +7,7 @@
 from kopf.reactor.causation import ResourceChangingCause
 from kopf.structs.bodies import Body
 from kopf.structs.dicts import parse_field
+from kopf.structs.diffs import DiffOperation, DiffItem
 from kopf.structs.filters import MetaFilterToken
 from kopf.structs.handlers import ResourceChangingHandler, Reason, ALL_REASONS
 
@@ -667,6 +668,50 @@ def some_fn(**_): ...
  handlers = registry.resource_changing_handlers[cause.resource].get_handlers(cause)
  assert not handlers
 
+
+#
+# Special case for nested fields with shorter/longer diffs.
+#
+
+def test_field_same_as_diff(cause_with_diff, registry, resource):
+
+ @kopf.on.field(resource.group, resource.version, resource.plural, registry=registry,
+ field='level1.level2')
+ def some_fn(**_): ...
+
+ cause = cause_with_diff
+ cause.reason = Reason.UPDATE
+ cause.diff = [DiffItem(DiffOperation.CHANGE, ('level1', 'level2'), 'old', 'new')]
+ handlers = registry.resource_changing_handlers[cause.resource].get_handlers(cause)
+ assert handlers
+
+
+def test_field_longer_than_diff(cause_with_diff, registry, resource):
+
+ @kopf.on.field(resource.group, resource.version, resource.plural, registry=registry,
+ field='level1.level2.level3')
+ def some_fn(**_): ...
+
+ cause = cause_with_diff
+ cause.reason = Reason.UPDATE
+ cause.diff = [DiffItem(DiffOperation.CHANGE, ('level1', 'level2'), 'old', 'new')]
+ handlers = registry.resource_changing_handlers[cause.resource].get_handlers(cause)
+ assert handlers
+
+
+def test_field_shorter_than_diff(cause_with_diff, registry, resource):
+
+ @kopf.on.field(resource.group, resource.version, resource.plural, registry=registry,
+ field='level1')
+ def some_fn(**_): ...
+
+ cause = cause_with_diff
+ cause.reason = Reason.UPDATE
+ cause.diff = [DiffItem(DiffOperation.CHANGE, ('level1', 'level2'), 'old', 'new')]
+ handlers = registry.resource_changing_handlers[cause.resource].get_handlers(cause)
+ assert handlers
+
+
 #
 # The handlers must be returned in order of registration,
 # even if they are mixed with-/without- * -event/-field handlers.