[SwiftWarningControl] Add ability to query warning group behavior including client-specified enclosing control rules

Sources/SwiftWarningControl/CMakeLists.txt

@@ -7,7 +7,7 @@
 # See http://swift.org/CONTRIBUTORS.txt for Swift project authors
 
 add_swift_syntax_library(SwiftWarningControl
-  WarningGroupBehavior.swift
+  WarningGroupControl.swift
   WarningControlDeclSyntax.swift
   WarningControlRegionBuilder.swift
   WarningControlRegions.swift

Sources/SwiftWarningControl/SwiftWarningControl.md

@@ -25,6 +25,6 @@ func foo() {
 
 The `SwiftWarningControl` library provides a utility to determine, for a given source location and diagnostic group identifier, whether or not its behavior is affected by an `@warn` attribute of any of its parent declaration scope. 
 
-* `SyntaxProtocol.getWarningGroupControl(for diagnosticGroupIdentifier:)` produces the behavior specifier (`WarningGroupBehavior`: `error`, `warning`, `ignored`) which applies at this node.
+* `SyntaxProtocol.getWarningGroupControl(for diagnosticGroupIdentifier:)` produces the behavior control specifier (`WarningGroupControl`: `error`, `warning`, `ignored`) which applies at this node.
 
-* `SyntaxProtocol.warningGroupControlRegionTree` holds a computed `WarningControlRegionTree` data structure value that can be used to efficiently test for the specified `WarningGroupBehavior` at a given source location and a given diagnostic group.
+* `SyntaxProtocol.warningGroupControlRegionTree` holds a computed `WarningControlRegionTree` data structure value that can be used to efficiently test for the specified `WarningGroupControl` at a given source location and a given diagnostic group.

Sources/SwiftWarningControl/SyntaxProtocol+WarningControl.swift

@@ -14,13 +14,25 @@ import SwiftDiagnostics
 import SwiftSyntax
 
 extension SyntaxProtocol {
-  /// Get the warning emission behavior for the specified diagnostic group
+  /// Get the warning emission behavior control for the specified diagnostic group
   /// by determining its containing `WarningControlRegion`, if one is present.
+  /// Returns the syntactic control for the given diagnostic group, or `nil` if
+  /// there is not one.
+  /// - Parameters:
+  ///   - for diagnosticGroupIdentifier: The identifier of the diagnostic group.
+  ///   - globalControls: The global controls to consider, specified by the client (compiler)
+  ///     representing module-wide diagnostic group emission configuration, for example
+  ///     with `-Wwarning` and `-Werror` flags. These controls can be overriden at
+  ///     finer-grained scopes with the `@warn` attribute.
   @_spi(ExperimentalLanguageFeatures)
-  public func warningGroupBehavior(
-    for diagnosticGroupIdentifier: DiagnosticGroupIdentifier
-  ) -> WarningGroupBehavior? {
-    let warningControlRegions = root.warningGroupControlRegionTreeImpl(containing: self.position)
-    return warningControlRegions.warningGroupBehavior(at: self.position, for: diagnosticGroupIdentifier)
+  public func warningGroupControl(
+    for diagnosticGroupIdentifier: DiagnosticGroupIdentifier,
+    globalControls: [DiagnosticGroupIdentifier: WarningGroupControl] = [:]
+  ) -> WarningGroupControl? {
+    let warningControlRegions = root.warningGroupControlRegionTreeImpl(
+      globalControls: globalControls,
+      containing: self.position
+    )
+    return warningControlRegions.warningGroupControl(at: self.position, for: diagnosticGroupIdentifier)
   }
 }

Sources/SwiftWarningControl/WarningControlDeclSyntax.swift

@@ -13,10 +13,10 @@
 import SwiftSyntax
 
 extension WithAttributesSyntax {
-  /// Compute a dictionary of all `@warn` diagnostic group behaviors
+  /// Compute a dictionary of all `@warn` diagnostic group behavior controls
   /// specified on this warning control declaration scope.
-  var allWarningGroupControls: [DiagnosticGroupIdentifier: WarningGroupBehavior] {
-    attributes.reduce(into: [DiagnosticGroupIdentifier: WarningGroupBehavior]()) { result, attr in
+  var allWarningGroupControls: [DiagnosticGroupIdentifier: WarningGroupControl] {
+    attributes.reduce(into: [DiagnosticGroupIdentifier: WarningGroupControl]()) { result, attr in
       // `@warn` attributes
       guard case .attribute(let attributeSyntax) = attr,
         attributeSyntax.attributeName.as(IdentifierTypeSyntax.self)?.name.text == "warn"
@@ -33,7 +33,7 @@ extension WithAttributesSyntax {
         return
       }
 
-      // Second argument is the `as: ` behavior specifier
+      // Second argument is the `as: ` behavior control specifier
       guard
         let asParamExprSyntax = attributeSyntax
           .arguments?.as(LabeledExprListSyntax.self)?
@@ -43,14 +43,14 @@ extension WithAttributesSyntax {
       }
       guard
         asParamExprSyntax.label?.text == "as",
-        let behaviorText = asParamExprSyntax
+        let controlText = asParamExprSyntax
           .expression.as(DeclReferenceExprSyntax.self)?
           .baseName.text,
-        let behavior = WarningGroupBehavior(rawValue: behaviorText)
+        let control = WarningGroupControl(rawValue: controlText)
       else {
         return
       }
-      result[DiagnosticGroupIdentifier(diagnosticGroupID)] = behavior
+      result[DiagnosticGroupIdentifier(diagnosticGroupID)] = control
     }
   }
 }

Sources/SwiftWarningControl/WarningControlRegionBuilder.swift

@@ -15,16 +15,22 @@ import SwiftSyntax
 /// Compute the full set of warning control regions in this syntax node
 extension SyntaxProtocol {
   @_spi(ExperimentalLanguageFeatures)
-  public func warningGroupControlRegionTree() -> WarningControlRegionTree {
-    return warningGroupControlRegionTreeImpl()
+  public func warningGroupControlRegionTree(
+    globalControls: [DiagnosticGroupIdentifier: WarningGroupControl] = [:]
+  ) -> WarningControlRegionTree {
+    return warningGroupControlRegionTreeImpl(globalControls: globalControls)
   }
 
   /// Implementation of constructing a region tree with an optional parameter
   /// to specify that the constructed tree must only contain nodes which contain
   /// a specific absolute position - meant to speed up tree generation for individual
   /// queries.
-  func warningGroupControlRegionTreeImpl(containing position: AbsolutePosition? = nil) -> WarningControlRegionTree {
+  func warningGroupControlRegionTreeImpl(
+    globalControls: [DiagnosticGroupIdentifier: WarningGroupControl],
+    containing position: AbsolutePosition? = nil
+  ) -> WarningControlRegionTree {
     let visitor = WarningControlRegionVisitor(self.range, containing: position)
+    visitor.tree.addWarningGroupControls(range: self.range, controls: globalControls)
     visitor.walk(self)
     return visitor.tree
   }

Sources/SwiftWarningControl/WarningControlRegions.swift

@@ -13,21 +13,21 @@
 import SwiftSyntax
 
 /// A single warning control region, consisting of a start and end positions,
-/// a diagnostic group identifier, and an emission behavior specifier.
+/// a diagnostic group identifier, and an emission behavior control specifier.
 @_spi(ExperimentalLanguageFeatures)
 public struct WarningControlRegion {
   public let range: Range<AbsolutePosition>
   public let diagnosticGroupIdentifier: DiagnosticGroupIdentifier
-  public let behavior: WarningGroupBehavior
+  public let control: WarningGroupControl
 
   init(
     range: Range<AbsolutePosition>,
     diagnosticGroupIdentifier: DiagnosticGroupIdentifier,
-    behavior: WarningGroupBehavior
+    control: WarningGroupControl
   ) {
     self.range = range
     self.diagnosticGroupIdentifier = diagnosticGroupIdentifier
-    self.behavior = behavior
+    self.control = control
   }
 }
 
@@ -98,9 +98,6 @@ public struct DiagnosticGroupIdentifier: Hashable, Sendable, ExpressibleByString
 /// traversal until we find the first containing region which specifies warning
 /// behavior control for the given diagnostic group id.
 ///
-/// TODO: Capture global configuration from command-line arguments
-///       to represent global rules, such as `-Werror`, `-Wwarning`,
-///       and `-suppress-warnings` as *the* root region node.
 @_spi(ExperimentalLanguageFeatures)
 public struct WarningControlRegionTree {
   /// Root region representing top-level (file) scope
@@ -113,11 +110,12 @@ public struct WarningControlRegionTree {
   /// Add a warning control region to the tree
   mutating func addWarningGroupControls(
     range: Range<AbsolutePosition>,
-    controls: [DiagnosticGroupIdentifier: WarningGroupBehavior]
+    controls: [DiagnosticGroupIdentifier: WarningGroupControl]
   ) {
+    guard !controls.isEmpty else { return }
     let newNode = WarningControlRegionNode(range: range)
-    for (diagnosticGroupIdentifier, behavior) in controls {
-      newNode.addWarningGroupControl(for: diagnosticGroupIdentifier, behavior: behavior)
+    for (diagnosticGroupIdentifier, control) in controls {
+      newNode.addWarningGroupControl(for: diagnosticGroupIdentifier, control: control)
     }
     insertIntoSubtree(newNode, parent: rootRegionNode)
   }
@@ -134,7 +132,7 @@ public struct WarningControlRegionTree {
     // Check if the new region has the same boundaries as the parent
     if parent.range == node.range {
       for (diagnosticGroupIdentifier, control) in node.warningGroupControls {
-        parent.addWarningGroupControl(for: diagnosticGroupIdentifier, behavior: control)
+        parent.addWarningGroupControl(for: diagnosticGroupIdentifier, control: control)
       }
       return
     }
@@ -157,7 +155,8 @@ extension WarningControlRegionTree: CustomDebugStringConvertible {
       let spacing = String(repeating: "  ", count: indent)
       result += "\(spacing)[\(node.range.lowerBound), \(node.range.upperBound)]"
       if !node.warningGroupControls.isEmpty {
-        result += " id(s): \(node.warningGroupControls.keys.map { $0.identifier }.joined(separator: ", "))\n"
+        result +=
+          " control(s): \(node.warningGroupControls.map { $0.key.identifier + ": " + $0.value.rawValue }.joined(separator: ", "))\n"
       } else {
         result += "\n"
       }
@@ -172,31 +171,31 @@ extension WarningControlRegionTree: CustomDebugStringConvertible {
 }
 
 extension WarningControlRegionTree {
-  /// Determine the warning group behavior at a specified position
-  /// for a given diagnostic group
+  /// Determine the warning group behavior control at a specified position
+  /// for a given diagnostic group.
   @_spi(ExperimentalLanguageFeatures)
-  public func warningGroupBehavior(
+  public func warningGroupControl(
     at position: AbsolutePosition,
     for diagnosticGroupIdentifier: DiagnosticGroupIdentifier
-  ) -> WarningGroupBehavior? {
-    return rootRegionNode.innermostContainingRegion(at: position, for: diagnosticGroupIdentifier)?.behavior
+  ) -> WarningGroupControl? {
+    return rootRegionNode.innermostContainingRegion(at: position, for: diagnosticGroupIdentifier)?.control
   }
 }
 
 /// A node in the warning control region tree, representing a collection of warning
 /// group controls and references to its nested child regions.
 private class WarningControlRegionNode {
   let range: Range<AbsolutePosition>
-  var warningGroupControls: [DiagnosticGroupIdentifier: WarningGroupBehavior] = [:]
+  var warningGroupControls: [DiagnosticGroupIdentifier: WarningGroupControl] = [:]
   var children: [WarningControlRegionNode] = []
 
   init(
     range: Range<AbsolutePosition>,
     for diagnosticGroupIdentifier: DiagnosticGroupIdentifier,
-    behavior: WarningGroupBehavior
+    control: WarningGroupControl
   ) {
     self.range = range
-    self.warningGroupControls = [diagnosticGroupIdentifier: behavior]
+    self.warningGroupControls = [diagnosticGroupIdentifier: control]
   }
 
   init(range: Range<AbsolutePosition>) {
@@ -207,20 +206,20 @@ private class WarningControlRegionNode {
   /// Add a region with the same bounds as this node
   func addWarningGroupControl(
     for diagnosticGroupIdentifier: DiagnosticGroupIdentifier,
-    behavior: WarningGroupBehavior
+    control: WarningGroupControl
   ) {
-    warningGroupControls[diagnosticGroupIdentifier] = behavior
+    warningGroupControls[diagnosticGroupIdentifier] = control
   }
 
   /// Get region with specific identifier if it exists
   func getWarningGroupControl(for diagnosticGroupIdentifier: DiagnosticGroupIdentifier) -> WarningControlRegion? {
-    guard let behaviorControl = warningGroupControls[diagnosticGroupIdentifier] else {
+    guard let groupControl = warningGroupControls[diagnosticGroupIdentifier] else {
       return nil
     }
     return WarningControlRegion(
       range: range,
       diagnosticGroupIdentifier: diagnosticGroupIdentifier,
-      behavior: behaviorControl
+      control: groupControl
     )
   }
 

Sources/SwiftWarningControl/WarningGroupBehavior.swift → Sources/SwiftWarningControl/WarningGroupControl.swift

@@ -14,7 +14,7 @@ import SwiftSyntax
 
 // Describes the emission behavior state of a particular warning diagnostic group.
 @_spi(ExperimentalLanguageFeatures)
-public enum WarningGroupBehavior: String {
+public enum WarningGroupControl: String {
   /// Emitted as a fatal error, halting compilation
   case error
   /// Emitted as a warning

Tests/SwiftWarningControlTest/WarningControlTests.swift

@@ -228,14 +228,66 @@ public class WarningGroupControlTests: XCTestCase {
       ]
     )
   }
+
+  func testEnclosingGlobalControlOverride() throws {
+    // Global control does not override syntactic control
+    try assertWarningGroupControl(
+      """
+      @warn(GroupID, as: error)
+      func foo() {
+        1️⃣let x = 1
+      }
+      """,
+      globalControls: ["GroupID": .warning],
+      diagnosticGroupID: "GroupID",
+      states: [
+        "1️⃣": .error
+      ]
+    )
+
+    try assertWarningGroupControl(
+      """
+      func foo() {
+        1️⃣let x = 1
+        @warn(GroupID, as: ignored)
+        func bar() {
+          2️⃣let x = 1
+        }
+      }
+      """,
+      globalControls: ["GroupID": .error],
+      diagnosticGroupID: "GroupID",
+      states: [
+        "1️⃣": .error,
+        "2️⃣": .ignored,
+      ]
+    )
+  }
+
+  func testEnclosingGlobalControlOnly() throws {
+    // Global control used in absense of a syntactic control
+    try assertWarningGroupControl(
+      """
+      func foo() {
+        1️⃣let x = 1
+      }
+      """,
+      globalControls: ["GroupID": .warning],
+      diagnosticGroupID: "GroupID",
+      states: [
+        "1️⃣": .warning
+      ]
+    )
+  }
 }
 
 /// Assert that the various marked positions in the source code have the
 /// expected warning behavior controls.
 private func assertWarningGroupControl(
   _ markedSource: String,
+  globalControls: [DiagnosticGroupIdentifier: WarningGroupControl] = [:],
   diagnosticGroupID: DiagnosticGroupIdentifier,
-  states: [String: WarningGroupBehavior?],
+  states: [String: WarningGroupControl?],
   file: StaticString = #filePath,
   line: UInt = #line
 ) throws {
@@ -244,9 +296,6 @@ private func assertWarningGroupControl(
 
   var parser = Parser(source)
   let tree = SourceFileSyntax.parse(from: &parser)
-
-  let warningControlRegions = tree.warningGroupControlRegionTree()
-
   for (marker, location) in markerLocations {
     guard let expectedState = states[marker] else {
       XCTFail("Missing marker \(marker) in expected states", file: file, line: line)
@@ -259,13 +308,17 @@ private func assertWarningGroupControl(
       continue
     }
 
-    let groupBehavior = token.warningGroupBehavior(for: diagnosticGroupID)
-    XCTAssertEqual(groupBehavior, expectedState)
+    let warningControlRegions = tree.warningGroupControlRegionTree(globalControls: globalControls)
+    let groupControl = token.warningGroupControl(
+      for: diagnosticGroupID,
+      globalControls: globalControls
+    )
+    XCTAssertEqual(groupControl, expectedState)
 
-    let groupBehaviorViaRegions = warningControlRegions.warningGroupBehavior(
+    let groupControlViaRegions = warningControlRegions.warningGroupControl(
       at: absolutePosition,
       for: diagnosticGroupID
     )
-    XCTAssertEqual(groupBehaviorViaRegions, expectedState)
+    XCTAssertEqual(groupControlViaRegions, expectedState)
   }
 }