Commits on Aug 15, 2022

1. Plugins: no server; interface contravariant; no factory functions …

   Previously on `version-4`, we had made `ApolloServerPlugin<TContext>`
   "invariant" in `TContext` via the new `in out` annotation. That's
   because we had added a `server` field to `GraphQLRequestContext` and
   `GraphQLServerContext`.
   
   The issue here is that because you can invoke
   `server.executeOperation(op, contextValue)`, then a
   `ApolloServerPlugin<BaseContext>` was not assignable to
   `ApolloServerPlugin<SomeSpecificContext>`, because the former was able
   to call `requestContext.executeOperation(op, {})`, and a server whose
   context has additional required fields could not load this plugin. This
   essentially meant that you couldn't have a single object (not created by
   a generic function or generic class) that was a plugin that works with
   any server, even if it doesn't actually care about context values at
   all.
   
   When trying to dogfood AS4 it became clear that this was annoying. So
   let's fix it by removing `server` from those objects and making
   `ApolloServerPlugin` "contravariant" instead. This means that plugins
   can only *receive* `contextValue`, not *send* it. And so
   `ApolloServerPlugin<BaseContext>` (a plugin that doesn't bother to read
   any fields from `contextValue`) can be assigned to
   `ApolloServerPlugin<SpecificContext>` (a plugin that is permitted to
   read specific fields on `contextValue`, though it may choose not to).
   
   After removing `server`, restore `logger` (now `readonly`) and `cache`
   to `GraphQLRequestContext` and `GraphQLServerContext` (`cache` is
   actually new to `GraphQLServerContext` in AS4). They had previously been
   removed for redundancy.
   
   This un-does the fix to #6264. If your plugin needs access to the
   `server` object, you can just pass it to your plugin's
   constructor/factory yourself. This wasn't an option in AS3 because there
   was no `server.addPlugin` method... or actually, you could do it with
   the plugin factory feature.
   
   Note that we do leave `ApolloServer<TContext>` as invariant in
   `TContext`, for the reasons described in a comment above the class.
   
   While we're at it, remove the unnecessary ability to specify plugins as
   factory functions. As far as we know, the main use case for this feature
   is to refer to the `ApolloServer` itself in the expression creating the
   plugin, but the new `addPlugin` method lets you do the same thing.
   Reducing the number of ways to specify constructor options helps keep
   type errors simpler.

   

   glasser committed Aug 15, 2022
   Configuration menu

   • View commit details
   • Copy full SHA for f5b4133
   • Browse repository at this point

   Copy the full SHA

   f5b4133 View commit details

   Browse the repository at this point in the history