Adding an item to `AsyncQueue` was linear in the number of pending queue items, thus adding n items to an `AsyncQueue` before any can execute is in O(n^2). This decision was made intentionally because the primary use case for `AsyncQueue` was to track pending LSP requests, of which we don’t expect to have too many pending requests at any given time.
While we can't fix the quadratic performance issue in general, we can resolve the quadratic issue of `AsyncQueue<Serial>` by making a new task only depend on the last item in the queue, which then transitively depends on all the previous items. `AsyncQueue<Serial>` are the queues that are most likely to contain many items.
Fixes#1725
rdar://137886469
We made quite a few fixes recently to make sure that path handling works correctly using `URL` on Windows. Use `URL` in most places to have a single type that represents file paths instead of sometimes using `AbsolutePath`.
While doing so, also remove usages of `TSCBasic.FileSystem` an `InMemoryFileSystem`. The pattern of using `InMemoryFileSystem` for tests was never consistently used and it was a little confusing that some types took a `FileSystem` parameter while other always assumed to work on the local file system.
`URL.path` returns forward slashes in the path on Windows (https://github.com/swiftlang/swift-foundation/issues/973) where we expect backslashes. Work around that by defining our own `filePath` property that is backed by `withUnsafeFileSystemRepresentation`, which produces backslashes.
rdar://137963660
When we receive build settings after hitting the timeout, we call `fileBuildSettingsChanged` on the delegate, which should cause the document to get re-opened in sourcekitd and diagnostics to get refreshed.
rdar://136332685
Fixes#1693
The build server is automatically shut down using a background task when `BuildSystemManager` is deallocated.
This, however, leads to possible race conditions where the shutdown task might not finish before the test is done, which could result in the connection being reported as a leak. To avoid this problem, we want to explicitly shut, down the build server when the `SourceKitLSPServer` gets shut down.
When we receive build settings after hitting the timeout, we call `fileBuildSettingsChanged` on the delegate, which should cause the document to get re-opened in sourcekitd and diagnostics to get refreshed.
rdar://136332685
If a BSP server crashes, we should try to relaunch it. Use a similar relaunch logic as the one we use for `clangd`: Try restarting immediately unless the BSP server has crashed within the last 30 seconds, in which case we delay the restart by 10s.
rdar://136311009
Fixes#1686
