We currently load the entire package before generating a `SwiftPMBuildSystem`. That means that the initialize request to SourceKit-LSP is blocked until the package has been loaded, preventing us from offering any sort of functionality, including syntactic functionality like formatting.
Decouple build system creation and build graph generation (aka. package loading for SwiftPM). We can operate with fallback build settings until the build graph has been loaded and reopen the document once the proper build settings are available.
rdar://126644596
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
