I saw a nondeterministic test failure of `AsyncUtilsTests.testWithTimeoutEscalatesPriority` and I believe this was the cause.
Also refactor a few test helper functions on the way.
Change a l public declarations to the `package` access level, accept for:
- The `LanguageServerProtocol` module
- The `BuildServerProtocol` module
- `InProcessClient.InProcessSourceKitLSPClient`
- `LanguageServerProtocolJSONRPC` (I would like to create a more ergonomic API for this like `InProcessSourceKitLSPClient` in the future, but for now, we’ll leave it public)
Unfortunately, our pattern of marking functions as `@_spi(Testing) public` no longer works with the `package` access level because declarations at the `package` access level cannot be marked as SPI. I have decided to just mark these functions as `package`. Alternatives would be:
- Add an underscore to these functions, like we did for functions exposed for testing before the introduction of `SPI`
- Use `@testable` import in the test targets and mark the methods as `internal`
Resolves#1315
rdar://128295618
Unfortunately, `setpriority` only allows reduction of a process’s priority and doesn’t support priority elevation (unless you are a super user). I still think that it’s valuable to set the process’s priority based on the task priority when it is launched because many indexing processes never get their priority escalated and should thus run in the background.
On Windows, we can elevate the process’s priority.
rdar://127474245
