refactor: remove net-stubbing->server->net-stubbing cycle

[cacieprins]

• Closes

Additional details

Small refactor to break the @packages/server <> @packages/net-stubbing cycle, informed by SOLID principles (dependency inversion,

• @packages/net-stubbing now depends directly on @packages/errors, rather than importing @packages/errors via @packages/server re-exporting it
• CyServer.Socket definition is removed, and SocketBroadcaster is added as a type that @packages/socket exports
• @packages/net-stubbing and @packages/proxy import SocketBroadcaster from @packages/socket instead of CyServer.Socket from `@packagbes/server
• @packages/server is dropped as a dependency of @packages/net-stubbing

Dependency Inversion - rather than net-stubbing and proxy depending on server to define their public interface, server purely depends on them. server depends on proxy for the same interface, to ensure that classes it implements conform to the contract.

Interface Segregation guides us to limit the scope of that interface to the "send message to driver" functionality: it is the bare minimum that net-stubbing and proxy need. It also guided us to import @packages/errors directly, so that it is not depending on the entirety of @packages/server when all it's using is the cloneErr utility method from @packages/errors.

Single Responsibility guided us to move the SocketBroadcaster interface to a neutral thematically-appropriate package; @packages/server implements it in SocketBase, and net-stubbing/proxy consume it.

Potential extensions:

• Extract event wiring from socket-base into a separate function
• Limit socket-base to a single responsibility: initializing and broadcasting to a tuple of socket.io connections
• Try to update CDPSocketServer so that it implements socket-io.Server, so that the tuple is not two different types
• move socket-base to @packages/socket, slim down its public interface
• have net-stubbing and proxy depend on socket-io for the socket interface, rather than @packages/socket.
• No longer inherit SocketBase in SocketCt and SocketE2E.

This is composition over inheritence. CT/E2E sockets implement a small interface and use the SocketBroadcaster instead of being a subtype of a large base class (single responsibility). net-stubbing and proxy receive the SocketBroadcaster implementation of the interface/contract (liskov substitution). If CT/E2E sockets implement a small interface (like TestCoordinator or similar) and hold SocketBroadcaster internally, server depends on that interface only. No inheritence from a large base class means no forced dependency on methods not used (interface segregation). Server can also depend on an abstraction (TestCoordinator) instead of the concrete SocketBase hierarchy. High level (server) depends on the interface; low-level (CT/E2E sockets) implement it and use the shared broadcaster (dependency inversion).

Note that in the case of this codebase and its constraints, SOLID principles should be a guide rather than a requirement/constraint. Going whole-hog on them can make things more difficult to grok; it's a balance. Using them to address circular dependencies helps to not create bigger issues in the future, while breaking circular dependencies.

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Note

Low Risk
Type-only refactor to decouple packages; risk is mainly compile/runtime wiring mismatches around toDriver event emission.

Overview
Breaks the @packages/server ↔ @packages/net-stubbing circular dependency by replacing CyServer.Socket with a new SocketBroadcaster interface exported from @packages/socket.

Updates net-stubbing and proxy to type their socket dependency as SocketBroadcaster, makes server’s SocketBase implement that interface, and removes the CyServer.Socket type from packages/server/index.d.ts. net-stubbing also stops importing server re-exported errors by switching its middleware to import @packages/errors directly, and both net-stubbing and proxy add @packages/socket as a dependency (with net-stubbing dropping @packages/server).

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Steps to test

How has the user experience changed?

PR Tasks

• [NA] Have tests been added/updated?
• [NA] Has a PR for user-facing changes been opened in cypress-documentation?
• [NA] Have API changes been updated in the type definitions?

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[cypress]

cypress    Run #69096

Run Properties:   Passed #69096  •  e96107f94f: Update socket-broadcaster.ts - remove toRunner

Project	cypress
Branch Review	refactor/net-server-errors-cycle
Run status	Passed #69096
Run duration	18m 55s
Commit	e96107f94f: Update socket-broadcaster.ts - remove toRunner
Committer	Cacie Prins
View all properties for this run ↗︎

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Test results
Failures	0
Flaky	10
Pending	1112
Skipped	0
Passing	27185
View all changes introduced in this branch ↗︎

UI Coverage  61.04%
Untested elements	28
Tested elements	47

Accessibility  99%
Failed rules	0 critical   3 serious   1 moderate   0 minor
Failed elements	18