feat: Add context parameter to InternalProvider and JsonRpcServer methods

[rekmarks]

Explanation

Adds a MiddlewareContext parameter to InternalProvider.request() and JsonRpcServer.handle(). This is essentially a missing feature from the JsonRpcEngineV2 implementation / migration, since callers are no longer able to add non-JSON-RPC properties to request objects and instead need to use the context object.

As part of this, permit specifying a plain object as the context to avoid forcing callers to import MiddlewareContext whenever they want to make a JSON-RPC call with some particular context. Also opportunistically fixes a bug with the static isInstance methods of V2 engine classes, where we wouldn't walk the prototype chain when checking for the symbol property.

References

• Related to Migrate JSON-RPC stack to JsonRpcEngineV2 #6327

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've communicated my changes to consumers by updating changelogs for packages I've changed, highlighting breaking changes as necessary
• I've prepared draft pull requests for clients and consumer packages to resolve any breaking changes
  • These changes are non-breaking, and will in any event be exhaustively covered via preview builds through refactor!: Migrate eth-json-rpc-middleware to JsonRpcEngineV2 #7065.

---

Note

Adds a context option to InternalProvider.request()/JsonRpcServer.handle(), enables passing plain-object contexts across the V2 engine, makes PollingBlockTracker context-generic, and narrows Network Controller’s Provider type; updates tests/docs accordingly.

• JSON-RPC Engine (v2):
  • Add HandleOptions with context (accepts MiddlewareContext or plain object) and forward it through handle() and JsonRpcServer.handle().
  • Enhance MiddlewareContext (construct from KeyValues object, isInstance) and export InferKeyValues; add shared isInstance util; minor server refactor (static request coercion).
  • Update README and tests for context passing and utils.
• eth-json-rpc-provider:
  • Make InternalProvider generic over Context; request() accepts { context } and forwards to engine.
  • Update tests and CHANGELOG.
• eth-block-tracker:
  • Genericize PollingBlockTracker with Context; type provider as InternalProvider<Context>; update CHANGELOG.
• Network Controller:
  • Narrow Provider to InternalProvider<MiddlewareContext<{ origin: string; skipCache: boolean } & Record<string, unknown>>>.
  • Type updates in create-network-client, tests, and helpers; update CHANGELOG.
• Tests/Utilities:
  • Update fakes (FakeProvider, FakeBlockTracker) and consumers to new generic/context types.
  • Bridge controller test now uses @metamask/network-controllerProvider.
• Deps:
  • Add @metamask/network-controller to root package.json.

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[mcmire]

One question, but overall looks good to me.

[mcmire]

Nit: Indentation?

Suggested change

	ContextextendsContextConstraint=MiddlewareContext,
	>
	ContextextendsContextConstraint=MiddlewareContext,
	>

[rekmarks]

This is what Prettier wants (there are no lint warnings or errors in the entire package).

[mcmire]

Boo. Fine then 😆

[mcmire]

I did not know you could have a static private property 🤔

Thoughts on making it public? Or maybe it doesn't need to be a static property on JsonRpcServer, it can be a function in utils?

[rekmarks]

Yeah, static private properties are neat! I only made this one static because I noticed that I could.

I don't really want to make the method public, because using it "correctly" requires capturing the original id beforehand as we do in handle(). I could make it into a external utility function and not export it if you have a strong preference for that?

[mcmire]

Oh I see, for some reason I thought it was being referenced outside of this class and got confused how that was working.

I don't have a strong preference for this in that case.

[mcmire]

Nice feature :)

[mcmire]

LGTM!

[rekmarks]

Skipping review from @MetaMask/swaps-engineers; we changed a type in a test.