Merge pull request swiftlang#243 from DavidGoldman/letsgetvirtual

Disable diagnostics for blacklisted document schemes

Author: benlangmuir

Sources/LanguageServerProtocol/SupportTypes/DocumentURI.swift

@@ -24,6 +24,11 @@ public struct DocumentURI: Codable, Hashable {
     }
   }
 
+  /// The document's URL scheme, if present.
+  public var scheme: String? {
+    return storage.scheme
+  }
+
   /// Returns a filepath if the URI is a URL. If the URI is not a URL, returns
   /// the full URI as a fallback.
   /// This value is intended to be used when interacting with sourcekitd which

Sources/SourceKit/sourcekitd/SwiftLanguageServer.swift

@@ -37,6 +37,27 @@ fileprivate extension Range {
   }
 }
 
+/// Explicitly blacklisted `DocumentURI` schemes.
+fileprivate let excludedDocumentURISchemes: [String] = [
+  "git",
+  "hg",
+]
+
+/// Returns true if diagnostics should be emitted for the given document.
+///
+/// Some editors  (like Visual Studio Code) use non-file URLs to manage source control diff bases
+/// for the active document, which can lead to duplicate diagnostics in the Problems view.
+/// As a workaround we explicitly blacklist those URIs and don't emit diagnostics for them.
+///
+/// Additionally, as of Xcode 11.4, sourcekitd does not properly handle non-file URLs when
+/// the `-working-directory` argument is passed since it incorrectly applies it to the input
+/// argument but not the internal primary file, leading sourcekitd to believe that the input
+/// file is missing.
+fileprivate func diagnosticsEnabled(for document: DocumentURI) -> Bool {
+  guard let scheme = document.scheme else { return true }
+  return !excludedDocumentURISchemes.contains(scheme)
+}
+
 public final class SwiftLanguageServer: ToolchainLanguageServer {
 
   /// The server's request queue, used to serialize requests and responses to `sourcekitd`.
@@ -79,6 +100,12 @@ public final class SwiftLanguageServer: ToolchainLanguageServer {
     response: SKResponseDictionary,
     for snapshot: DocumentSnapshot)
   {
+    let documentUri = snapshot.document.uri
+    guard diagnosticsEnabled(for: documentUri) else {
+      log("Ignoring diagnostics for blacklisted file \(documentUri.pseudoPath)", level: .debug)
+      return
+    }
+
     let stageUID: sourcekitd_uid_t? = response[sourcekitd.keys.diagnostic_stage]
     let stage = stageUID.flatMap { DiagnosticStage($0, sourcekitd: sourcekitd) } ?? .sema
 

Tests/SourceKitTests/LocalSwiftTests.swift

@@ -307,6 +307,41 @@ final class LocalSwiftTests: XCTestCase {
     })
   }
 
+  func testExcludedDocumentSchemeDiagnostics() {
+    let includedURL = URL(fileURLWithPath: "/a.swift")
+    let includedURI = DocumentURI(includedURL)
+
+    let excludedURI = DocumentURI(string: "git:/a.swift")
+
+    let text = """
+    func
+    """
+
+    sk.allowUnexpectedNotification = false
+
+    // Open the excluded URI first so our later notification handlers can confirm
+    // that no diagnostics were emitted for this excluded URI.
+    sk.send(DidOpenTextDocumentNotification(textDocument: TextDocumentItem(
+      uri: excludedURI,
+      language: .swift,
+      version: 1,
+      text: text
+    )))
+
+    sk.sendNoteSync(DidOpenTextDocumentNotification(textDocument: TextDocumentItem(
+      uri: includedURI,
+      language: .swift,
+      version: 1,
+      text: text
+    )), { (note: Notification<PublishDiagnosticsNotification>) in
+      log("Received diagnostics for open - syntactic")
+      XCTAssertEqual(note.params.uri, includedURI)
+    }, { (note: Notification<PublishDiagnosticsNotification>) in
+      log("Received diagnostics for open - semantic")
+      XCTAssertEqual(note.params.uri, includedURI)
+    })
+  }
+
   func testCrossFileDiagnostics() {
     let urlA = URL(fileURLWithPath: "/a.swift")
     let urlB = URL(fileURLWithPath: "/b.swift")

Tests/SourceKitTests/XCTestManifests.swift

@@ -109,6 +109,7 @@ extension LocalSwiftTests {
         ("testEditing", testEditing),
         ("testEditingNonURL", testEditingNonURL),
         ("testEditorPlaceholderParsing", testEditorPlaceholderParsing),
+        ("testExcludedDocumentSchemeDiagnostics", testExcludedDocumentSchemeDiagnostics),
         ("testFixitInsert", testFixitInsert),
         ("testFixitsAreIncludedInPublishDiagnostics", testFixitsAreIncludedInPublishDiagnostics),
         ("testFixitsAreIncludedInPublishDiagnosticsNotes", testFixitsAreIncludedInPublishDiagnosticsNotes),