feat(feature-activation): automatically enable support in MUST_SIGNAL

hathor/feature_activation/bit_signaling_service.py

@@ -56,6 +56,7 @@ def __init__(
         self._feature_storage = feature_storage
 
         self._validate_support_intersection()
+        self._feature_service.bit_signaling_service = self
 
     def start(self) -> None:
         """
@@ -136,6 +137,12 @@ def remove_feature_support(self, feature: Feature) -> None:
         self._support_features.discard(feature)
         self._not_support_features.add(feature)
 
+    def on_must_signal(self, feature: Feature) -> None:
+        """
+        When the MUST_SIGNAL phase is reached, feature support is automatically enabled.
+        """
+        self.add_feature_support(feature)
+
     def _log_signal_bits(self, feature: Feature, enable_bit: bool, support: bool, not_support: bool) -> None:
         """Generate info log for a feature's signal."""
         signal = 'enabled' if enable_bit else 'disabled'

hathor/feature_activation/feature_service.py

@@ -13,14 +13,15 @@
 #  limitations under the License.
 
 from dataclasses import dataclass
-from typing import TYPE_CHECKING, TypeAlias
+from typing import TYPE_CHECKING, Optional, TypeAlias
 
 from hathor.feature_activation.feature import Feature
 from hathor.feature_activation.model.feature_description import FeatureDescription
 from hathor.feature_activation.model.feature_state import FeatureState
 from hathor.feature_activation.settings import Settings as FeatureSettings
 
 if TYPE_CHECKING:
+    from hathor.feature_activation.bit_signaling_service import BitSignalingService
     from hathor.transaction import Block
     from hathor.transaction.storage import TransactionStorage
 
@@ -41,11 +42,12 @@ class BlockIsMissingSignal:
 
 
 class FeatureService:
-    __slots__ = ('_feature_settings', '_tx_storage')
+    __slots__ = ('_feature_settings', '_tx_storage', 'bit_signaling_service')
 
     def __init__(self, *, feature_settings: FeatureSettings, tx_storage: 'TransactionStorage') -> None:
         self._feature_settings = feature_settings
         self._tx_storage = tx_storage
+        self.bit_signaling_service: Optional['BitSignalingService'] = None
 
     def is_feature_active(self, *, block: 'Block', feature: Feature) -> bool:
         """Returns whether a Feature is active at a certain block."""
@@ -113,6 +115,10 @@ def get_state(self, *, block: 'Block', feature: Feature) -> FeatureState:
             previous_state=previous_boundary_state
         )
 
+        if new_state == FeatureState.MUST_SIGNAL:
+            assert self.bit_signaling_service is not None
+            self.bit_signaling_service.on_must_signal(feature)
+
         # We cache the just calculated state of the current block _without saving it_, as it may still be unverified,
         # so we cannot persist its metadata. That's why we cache and save the previous boundary block above.
         block.set_feature_state(feature=feature, state=new_state)

tests/feature_activation/test_bit_signaling_service.py

@@ -286,3 +286,35 @@ def get_bits_description_mock(block: Block) -> dict[Feature, FeatureDescription]
         best_block_hash='abc',
         non_signaling_features=non_signaling_features,
     )
+
+
+def test_on_must_signal_not_supported() -> None:
+    service = BitSignalingService(
+        feature_settings=Mock(),
+        feature_service=Mock(),
+        tx_storage=Mock(),
+        support_features=set(),
+        not_support_features={Feature.NOP_FEATURE_1},
+        feature_storage=Mock(),
+    )
+
+    service.on_must_signal(feature=Feature.NOP_FEATURE_1)
+
+    assert service._support_features == {Feature.NOP_FEATURE_1}
+    assert service._not_support_features == set()
+
+
+def test_on_must_signal_supported() -> None:
+    service = BitSignalingService(
+        feature_settings=Mock(),
+        feature_service=Mock(),
+        tx_storage=Mock(),
+        support_features=set(),
+        not_support_features=set(),
+        feature_storage=Mock(),
+    )
+
+    service.on_must_signal(feature=Feature.NOP_FEATURE_1)
+
+    assert service._support_features == {Feature.NOP_FEATURE_1}
+    assert service._not_support_features == set()

tests/feature_activation/test_feature_service.py

@@ -119,6 +119,7 @@ def service(feature_settings: FeatureSettings, tx_storage: TransactionStorage) -
         feature_settings=feature_settings,
         tx_storage=tx_storage
     )
+    service.bit_signaling_service = Mock()
 
     return service
 
@@ -169,6 +170,7 @@ def test_get_state_from_defined(
         feature_settings=feature_settings,
         tx_storage=tx_storage
     )
+    service.bit_signaling_service = Mock()
     block = block_mocks[block_height]
 
     result = service.get_state(block=block, feature=Feature.NOP_FEATURE_1)
@@ -200,6 +202,7 @@ def test_get_state_from_started_to_failed(
         feature_settings=feature_settings,
         tx_storage=tx_storage
     )
+    service.bit_signaling_service = Mock()
     block = block_mocks[block_height]
 
     result = service.get_state(block=block, feature=Feature.NOP_FEATURE_1)
@@ -231,11 +234,13 @@ def test_get_state_from_started_to_must_signal_on_timeout(
         feature_settings=feature_settings,
         tx_storage=tx_storage
     )
+    service.bit_signaling_service = Mock()
     block = block_mocks[block_height]
 
     result = service.get_state(block=block, feature=Feature.NOP_FEATURE_1)
 
     assert result == FeatureState.MUST_SIGNAL
+    service.bit_signaling_service.on_must_signal.assert_called_once_with(Feature.NOP_FEATURE_1)
 
 
 @pytest.mark.parametrize('block_height', [8, 9, 10, 11])
@@ -263,6 +268,7 @@ def test_get_state_from_started_to_locked_in_on_default_threshold(
         feature_settings=feature_settings,
         tx_storage=tx_storage
     )
+    service.bit_signaling_service = Mock()
     block = block_mocks[block_height]
 
     result = service.get_state(block=block, feature=Feature.NOP_FEATURE_1)
@@ -294,6 +300,7 @@ def test_get_state_from_started_to_locked_in_on_custom_threshold(
         feature_settings=feature_settings,
         tx_storage=tx_storage
     )
+    service.bit_signaling_service = Mock()
     block = block_mocks[block_height]
 
     result = service.get_state(block=block, feature=Feature.NOP_FEATURE_1)
@@ -333,6 +340,7 @@ def test_get_state_from_started_to_started(
         feature_settings=feature_settings,
         tx_storage=tx_storage
     )
+    service.bit_signaling_service = Mock()
     block = block_mocks[block_height]
 
     result = service.get_state(block=block, feature=Feature.NOP_FEATURE_1)
@@ -362,6 +370,7 @@ def test_get_state_from_must_signal_to_locked_in(
         feature_settings=feature_settings,
         tx_storage=tx_storage
     )
+    service.bit_signaling_service = Mock()
     block = block_mocks[block_height]
 
     result = service.get_state(block=block, feature=Feature.NOP_FEATURE_1)
@@ -394,6 +403,7 @@ def test_get_state_from_locked_in_to_active(
         feature_settings=feature_settings,
         tx_storage=tx_storage
     )
+    service.bit_signaling_service = Mock()
     block = block_mocks[block_height]
 
     result = service.get_state(block=block, feature=Feature.NOP_FEATURE_1)
@@ -426,6 +436,7 @@ def test_get_state_from_locked_in_to_locked_in(
         feature_settings=feature_settings,
         tx_storage=tx_storage
     )
+    service.bit_signaling_service = Mock()
     block = block_mocks[block_height]
 
     result = service.get_state(block=block, feature=Feature.NOP_FEATURE_1)
@@ -451,6 +462,7 @@ def test_get_state_from_active(block_mocks: list[Block], tx_storage: Transaction
         feature_settings=feature_settings,
         tx_storage=tx_storage
     )
+    service.bit_signaling_service = Mock()
     block = block_mocks[block_height]
 
     result = service.get_state(block=block, feature=Feature.NOP_FEATURE_1)
@@ -473,6 +485,7 @@ def test_caching_mechanism(block_mocks: list[Block], tx_storage: TransactionStor
         }
     )
     service = FeatureService(feature_settings=feature_settings, tx_storage=tx_storage)
+    service.bit_signaling_service = Mock()
     block = block_mocks[block_height]
     calculate_new_state_mock = Mock(wraps=service._calculate_new_state)
 
@@ -507,6 +520,7 @@ def test_is_feature_active(block_mocks: list[Block], tx_storage: TransactionStor
         feature_settings=feature_settings,
         tx_storage=tx_storage
     )
+    service.bit_signaling_service = Mock()
     block = block_mocks[block_height]
 
     result = service.is_feature_active(block=block, feature=Feature.NOP_FEATURE_1)
@@ -531,6 +545,7 @@ def test_get_state_from_failed(block_mocks: list[Block], tx_storage: Transaction
         feature_settings=feature_settings,
         tx_storage=tx_storage
     )
+    service.bit_signaling_service = Mock()
     block = block_mocks[block_height]
 
     result = service.get_state(block=block, feature=Feature.NOP_FEATURE_1)
@@ -559,6 +574,7 @@ def test_get_bits_description(tx_storage: TransactionStorage) -> None:
         feature_settings=feature_settings,
         tx_storage=tx_storage
     )
+    service.bit_signaling_service = Mock()
 
     def get_state(self: FeatureService, *, block: Block, feature: Feature) -> FeatureState:
         states = {
@@ -596,6 +612,7 @@ def test_get_ancestor_at_height_invalid(
     ancestor_height: int
 ) -> None:
     service = FeatureService(feature_settings=feature_settings, tx_storage=tx_storage)
+    service.bit_signaling_service = Mock()
     block = block_mocks[block_height]
 
     with pytest.raises(AssertionError) as e:
@@ -625,6 +642,7 @@ def test_get_ancestor_at_height(
     ancestor_height: int
 ) -> None:
     service = FeatureService(feature_settings=feature_settings, tx_storage=tx_storage)
+    service.bit_signaling_service = Mock()
     block = block_mocks[block_height]
     result = service._get_ancestor_at_height(block=block, ancestor_height=ancestor_height)
 
@@ -653,6 +671,7 @@ def test_get_ancestor_at_height_voided(
     ancestor_height: int
 ) -> None:
     service = FeatureService(feature_settings=feature_settings, tx_storage=tx_storage)
+    service.bit_signaling_service = Mock()
     block = block_mocks[block_height]
     parent_block = block_mocks[block_height - 1]
     parent_block.get_metadata().voided_by = {b'some'}
@@ -711,6 +730,7 @@ def test_check_must_signal(
         }
     )
     service = FeatureService(feature_settings=feature_settings, tx_storage=tx_storage)
+    service.bit_signaling_service = Mock()
     block = block_mocks[block_height]
 
     result = service.is_signaling_mandatory_features(block)