Sam Smith 84226b41b6 featureManager: Add DynamicConfigRequirement requirement ... We expect the vast majority of requirements and features to be defined in services as possible. However, there are some "complex" requirements that require additional application/HTTP request state. Unfortunately, service wiring is done before some of that state is available. I65702426 attempted to work around this by requiring clients of the Feature Manager to pass that additional state on every interaction with the system. Those complex requirements would then select the parts of the state that they required when it was required. However implementations of \IContextSource are God objects and their use should be limited. Whilst reviewing I65702426, Stephen Niedzielski mentioned that the application state being available is a requirement. This remarkably simple solution: - Keeps the Requirement interface and FeatureManager API free of God objects; - Is true to the nature of the Feature Manager - it makes clear and centralizes the various checks for application state being available across the codebase; and - Inject a Requirement implementations' dependencies at construction time It just so happens that the $wgFullyInitialised variable flags whether the application state is available... Changes: - Add the the FeatureManager\Requirements\DynamicConfigRequirement class and tests. The DynamicConfigRequirement lazily evaluates a single configuration value whenever ::isMet is invoked - Register an DynamicConfigRequirement instance, configured to evaluate $wgFullyInitialised while constructing the Vector.FeatureManager service Bug: T244481 Change-Id: I7a2cdc2dfdf20d78e4548f07cf53994563b234b3		2020-03-18 10:10:42 +00:00
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FeatureManagement	featureManager: Add DynamicConfigRequirement requirement	2020-03-18 10:10:42 +00:00