fix(remoteconfig): compare custom signals whose value is 0 or empty; don't build values from a missing parameter value

firebase_admin/remote_config.py

@@ -315,7 +315,9 @@ def evaluate(self):
 
                 if parameter_value_wrapper:
                     parameter_value = parameter_value_wrapper.get('value')
-                    self._config_values[key] = _Value('remote', parameter_value)
+                    # A conditional value without an explicit value does not override anything.
+                    if parameter_value is not None:
+                        self._config_values[key] = _Value('remote', parameter_value)
                     continue
 
                 if not default_value:
@@ -487,20 +489,19 @@ def evaluate_custom_signal_condition(self, custom_signal_condition,
         Returns:
           True if the condition is met, False otherwise.
         """
-        custom_signal_operator = custom_signal_condition.get('customSignalOperator') or {}
-        custom_signal_key = custom_signal_condition.get('customSignalKey') or {}
-        target_custom_signal_values = (
-            custom_signal_condition.get('targetCustomSignalValues') or {})
+        custom_signal_operator = custom_signal_condition.get('customSignalOperator')
+        custom_signal_key = custom_signal_condition.get('customSignalKey')
+        target_custom_signal_values = custom_signal_condition.get('targetCustomSignalValues')
 
         if not all([custom_signal_operator, custom_signal_key, target_custom_signal_values]):
             logger.warning("Missing operator, key, or target values for custom signal condition.")
             return False
 
-        if not target_custom_signal_values:
-            return False
-        actual_custom_signal_value = context.get(custom_signal_key) or {}
+        # A signal is only absent when the context has no entry for it. Values such as 0 or ''
+        # are valid signals (the context is typed as Union[str, int]) and must be compared.
+        actual_custom_signal_value = context.get(custom_signal_key)
 
-        if not actual_custom_signal_value:
+        if actual_custom_signal_value is None:
             logger.debug("Custom signal value not found in context: %s", custom_signal_key)
             return False
 
@@ -725,7 +726,8 @@ def __init__(self, source: ValueSource, value: str = DEFAULT_VALUE_FOR_STRING):
           value: The string value.
         """
         self.source = source
-        self.value = value
+        # The getters assume a string payload, so a missing value must not end up as None.
+        self.value = value if value is not None else self.DEFAULT_VALUE_FOR_STRING
 
     def as_string(self) -> str:
         """Returns the value as a string."""
@@ -739,7 +741,7 @@ def as_boolean(self) -> bool:
             return self.DEFAULT_VALUE_FOR_BOOLEAN
         return str(self.value).lower() in self.BOOLEAN_TRUTHY_VALUES
 
-    def as_int(self) -> float:
+    def as_int(self) -> int:
         """Returns the value as a number."""
         if self.source == 'static':
             return self.DEFAULT_VALUE_FOR_INTEGER

tests/test_remote_config.py

@@ -301,6 +301,40 @@ def test_evaluate_default_when_no_default_value(self):
         server_config = server_template.evaluate()
         assert server_config.get_string('default_value') == default_config.get('default_value')
 
+    def test_evaluate_conditional_value_without_explicit_value(self):
+        app = firebase_admin.get_app()
+        default_config = {'dog_type': 'shiba'}
+        template_data = SERVER_REMOTE_CONFIG_RESPONSE
+        template_data['conditions'] = [{'name': 'is_true', 'condition': {'true': {}}}]
+        template_data['parameters'] = {
+            'dog_type': {
+                'conditionalValues': {'is_true': {'useInAppDefault': False}}
+            }
+        }
+        server_template = remote_config.init_server_template(
+            app=app,
+            default_config=default_config,
+            template_data_json=json.dumps(template_data)
+        )
+        server_config = server_template.evaluate()
+        assert server_config.get_string('dog_type') == default_config.get('dog_type')
+
+    def test_evaluate_default_value_without_explicit_value(self):
+        app = firebase_admin.get_app()
+        default_config = {'dog_type': 'shiba'}
+        template_data = SERVER_REMOTE_CONFIG_RESPONSE
+        template_data['parameters'] = {
+            'dog_type': {'defaultValue': {'useInAppDefault': False}}
+        }
+        server_template = remote_config.init_server_template(
+            app=app,
+            default_config=default_config,
+            template_data_json=json.dumps(template_data)
+        )
+        server_config = server_template.evaluate()
+        assert server_config.get_string('dog_type') == ''
+        assert server_config.get_int('dog_type') == 0
+
     def test_evaluate_default_when_in_default(self):
         app = firebase_admin.get_app()
         template_data = SERVER_REMOTE_CONFIG_RESPONSE
@@ -819,6 +853,58 @@ def test_evaluate_custom_signal_semantic_version(self,
         server_config = server_template.evaluate(context)
         assert server_config.get_boolean('is_enabled') == parameter_value
 
+    @pytest.mark.parametrize(
+        'custom_signal_operator, target_custom_signal_values, context_value',
+        [
+            (CustomSignalOperator.STRING_CONTAINS.value, ['0'], 0),
+            (CustomSignalOperator.NUMERIC_EQUAL.value, ['0'], 0),
+            (CustomSignalOperator.NUMERIC_GREATER_EQUAL.value, ['0'], 0),
+            (CustomSignalOperator.SEMANTIC_VERSION_EQUAL.value, ['0.0.0'], 0),
+            (CustomSignalOperator.STRING_EXACTLY_MATCHES.value, [''], ''),
+        ])
+    def test_evaluate_custom_signal_with_falsy_value(self,
+                                                     custom_signal_operator,
+                                                     target_custom_signal_values,
+                                                     context_value):
+        app = firebase_admin.get_app()
+        condition = {
+            'name': 'is_true',
+            'condition': {
+                'orCondition': {
+                    'conditions': [{
+                        'andCondition': {
+                            'conditions': [{
+                                'customSignal': {
+                                    'customSignalOperator': custom_signal_operator,
+                                    'customSignalKey': 'signal_key',
+                                    'targetCustomSignalValues': target_custom_signal_values
+                                }
+                            }],
+                        }
+                    }]
+                }
+            }
+        }
+        template_data = {
+            'conditions': [condition],
+            'parameters': {
+                'is_enabled': {
+                    'defaultValue': {'value': 'false'},
+                    'conditionalValues': {'is_true': {'value': 'true'}}
+                },
+            },
+            'parameterGroups': '',
+            'version': '',
+            'etag': '123'
+        }
+        server_template = remote_config.init_server_template(
+            app=app,
+            default_config={},
+            template_data_json=json.dumps(template_data)
+        )
+        server_config = server_template.evaluate({'signal_key': context_value})
+        assert server_config.get_boolean('is_enabled')
+
 
 class MockAdapter(testutils.MockAdapter):
     """A Mock HTTP Adapter that provides Firebase Remote Config responses with ETag in header."""