Migrate Diagnostics to Explicitly-Scheduled Pass

The new Swift Parser does not emit diagnostics on its own. Schedule
the diagnostic pass in all of the places SwiftFormat provides a
diagnostic hook.

Author: CodaFi

Sources/SwiftFormat/SwiftFormatter.swift

@@ -17,6 +17,7 @@ import SwiftFormatPrettyPrint
 import SwiftFormatRules
 import SwiftSyntax
 import SwiftParser
+import SwiftDiagnostics
 
 /// Formats Swift source code or syntax trees according to the Swift style guidelines.
 public final class SwiftFormatter {
@@ -55,7 +56,7 @@ public final class SwiftFormatter {
   public func format<Output: TextOutputStream>(
     contentsOf url: URL,
     to outputStream: inout Output,
-    parsingDiagnosticHandler: ((Diagnostic) -> Void)? = nil
+    parsingDiagnosticHandler: ((Diagnostic, SourceLocation) -> Void)? = nil
   ) throws {
     guard FileManager.default.isReadableFile(atPath: url.path) else {
       throw SwiftFormatError.fileNotReadable
@@ -66,6 +67,14 @@ public final class SwiftFormatter {
     }
     let source = try String(contentsOf: url, encoding: .utf8)
     let sourceFile = try Parser.parse(source: source)
+    if let parsingDiagnosticHandler = parsingDiagnosticHandler {
+      let expectedConverter = SourceLocationConverter(file: url.path, tree: sourceFile)
+      let diagnostics = ParseDiagnosticsGenerator.diagnostics(for: sourceFile)
+      for diagnostic in diagnostics {
+        let location = diagnostic.location(converter: expectedConverter)
+        parsingDiagnosticHandler(diagnostic, location)
+      }
+    }
     try format(syntax: sourceFile, assumingFileURL: url, source: source, to: &outputStream)
   }
 
@@ -85,9 +94,17 @@ public final class SwiftFormatter {
     source: String,
     assumingFileURL url: URL?,
     to outputStream: inout Output,
-    parsingDiagnosticHandler: ((Diagnostic) -> Void)? = nil
+    parsingDiagnosticHandler: ((Diagnostic, SourceLocation) -> Void)? = nil
   ) throws {
     let sourceFile = try Parser.parse(source: source)
+    if let parsingDiagnosticHandler = parsingDiagnosticHandler {
+      let expectedConverter = SourceLocationConverter(file: url?.path ?? "<unknown>", tree: sourceFile)
+      let diagnostics = ParseDiagnosticsGenerator.diagnostics(for: sourceFile)
+      for diagnostic in diagnostics {
+        let location = diagnostic.location(converter: expectedConverter)
+        parsingDiagnosticHandler(diagnostic, location)
+      }
+    }
     try format(syntax: sourceFile, assumingFileURL: url, source: source, to: &outputStream)
   }
 

Sources/SwiftFormat/SwiftLinter.swift

@@ -18,6 +18,7 @@ import SwiftFormatRules
 import SwiftFormatWhitespaceLinter
 import SwiftSyntax
 import SwiftParser
+import SwiftDiagnostics
 
 /// Diagnoses and reports problems in Swift source code or syntax trees according to the Swift style
 /// guidelines.
@@ -53,7 +54,7 @@ public final class SwiftLinter {
   /// - Throws: If an unrecoverable error occurs when formatting the code.
   public func lint(
     contentsOf url: URL,
-    parsingDiagnosticHandler: ((Diagnostic) -> Void)? = nil
+    parsingDiagnosticHandler: ((Diagnostic, SourceLocation) -> Void)? = nil
   ) throws {
     guard FileManager.default.isReadableFile(atPath: url.path) else {
       throw SwiftFormatError.fileNotReadable
@@ -64,7 +65,8 @@ public final class SwiftLinter {
     }
     let source = try String(contentsOf: url, encoding: .utf8)
     let sourceFile = try Parser.parse(source: source)
-    try lint(syntax: sourceFile, assumingFileURL: url, source: source)
+    try lint(syntax: sourceFile, assumingFileURL: url,
+             source: source, parsingDiagnosticHandler: parsingDiagnosticHandler)
   }
 
   /// Lints the given Swift source code.
@@ -78,10 +80,11 @@ public final class SwiftLinter {
   public func lint(
     source: String,
     assumingFileURL url: URL,
-    parsingDiagnosticHandler: ((Diagnostic) -> Void)? = nil
+    parsingDiagnosticHandler: ((Diagnostic, SourceLocation) -> Void)? = nil
   ) throws {
     let sourceFile = try Parser.parse(source: source)
-    try lint(syntax: sourceFile, assumingFileURL: url, source: source)
+    try lint(syntax: sourceFile, assumingFileURL: url,
+             source: source, parsingDiagnosticHandler: parsingDiagnosticHandler)
   }
 
   /// Lints the given Swift syntax tree.
@@ -93,14 +96,29 @@ public final class SwiftLinter {
   ///   - url: A file URL denoting the filename/path that should be assumed for this syntax tree.
   /// - Throws: If an unrecoverable error occurs when formatting the code.
   public func lint(syntax: SourceFileSyntax, assumingFileURL url: URL) throws {
-    try lint(syntax: syntax, assumingFileURL: url, source: nil)
+    try lint(syntax: syntax, assumingFileURL: url,
+             source: nil, parsingDiagnosticHandler: nil)
   }
 
-  private func lint(syntax: SourceFileSyntax, assumingFileURL url: URL, source: String?) throws {
+  private func lint(
+    syntax: SourceFileSyntax,
+    assumingFileURL url: URL,
+    source: String?,
+    parsingDiagnosticHandler: ((Diagnostic, SourceLocation) -> Void)?
+  ) throws {
     if let position = _firstInvalidSyntaxPosition(in: Syntax(syntax)) {
       throw SwiftFormatError.fileContainsInvalidSyntax(position: position)
     }
 
+    if let parsingDiagnosticHandler = parsingDiagnosticHandler {
+      let expectedConverter = SourceLocationConverter(file: url.path, tree: syntax)
+      let diagnostics = ParseDiagnosticsGenerator.diagnostics(for: syntax)
+      for diagnostic in diagnostics {
+        let location = diagnostic.location(converter: expectedConverter)
+        parsingDiagnosticHandler(diagnostic, location)
+      }
+    }
+
     let context = Context(
       configuration: configuration, findingConsumer: findingConsumer, fileURL: url,
       sourceFileSyntax: syntax, source: source, ruleNameCache: ruleNameCache)

Sources/swift-format/Utilities/UnifiedDiagnosticsEngine.swift

@@ -12,6 +12,7 @@
 
 import SwiftFormatCore
 import SwiftSyntax
+import SwiftDiagnostics
 import TSCBasic
 
 /// Diagnostic data that retains the separation of a finding category (if present) from the rest of
@@ -113,24 +114,21 @@ final class UnifiedDiagnosticsEngine {
   /// Emits a diagnostic from the syntax parser and any of its associated notes.
   ///
   /// - Parameter diagnostic: The syntax parser diagnostic that should be emitted.
-  func consumeParserDiagnostic(_ diagnostic: SwiftSyntaxParser.Diagnostic) {
+  func consumeParserDiagnostic(
+    _ diagnostic: SwiftDiagnostics.Diagnostic,
+    _ location: SourceLocation
+  ) {
     diagnosticsEngine.emit(
-      diagnosticMessage(for: diagnostic.message),
-      location: diagnostic.location.map(UnifiedLocation.parserLocation))
-
-    for note in diagnostic.notes {
-      diagnosticsEngine.emit(
-        .note(UnifiedDiagnosticData(message: note.message.text)),
-        location: note.location.map(UnifiedLocation.parserLocation))
-    }
+      diagnosticMessage(for: diagnostic.diagMessage),
+      location: UnifiedLocation.parserLocation(location))
   }
 
   /// Converts a diagnostic message from the syntax parser into a diagnostic message that can be
   /// used by the `TSCBasic` diagnostics engine and returns it.
-  private func diagnosticMessage(for message: SwiftSyntaxParser.Diagnostic.Message)
+  private func diagnosticMessage(for message: SwiftDiagnostics.DiagnosticMessage)
     -> TSCBasic.Diagnostic.Message
   {
-    let data = UnifiedDiagnosticData(category: nil, message: message.text)
+    let data = UnifiedDiagnosticData(category: nil, message: message.message)
 
     switch message.severity {
     case .error: return .error(data)