Store test content in a custom metadata section.

Documentation/Porting.md

@@ -145,8 +145,10 @@ to load that information:
 +  let resourceName: Str255 = switch kind {
 +  case .testContent:
 +    "__swift5_tests"
++#if !SWT_NO_LEGACY_TEST_DISCOVERY
 +  case .typeMetadata:
 +    "__swift5_types"
++#endif
 +  }
 +
 +  let oldRefNum = CurResFile()
@@ -219,14 +221,18 @@ diff --git a/Sources/_TestingInternals/Discovery.cpp b/Sources/_TestingInternals
 +#elif defined(macintosh)
 +extern "C" const char testContentSectionBegin __asm__("...");
 +extern "C" const char testContentSectionEnd __asm__("...");
++#if !defined(SWT_NO_LEGACY_TEST_DISCOVERY)
 +extern "C" const char typeMetadataSectionBegin __asm__("...");
 +extern "C" const char typeMetadataSectionEnd __asm__("...");
++#endif
  #else
  #warning Platform-specific implementation missing: Runtime test discovery unavailable (static)
  static const char testContentSectionBegin = 0;
  static const char& testContentSectionEnd = testContentSectionBegin;
+ #if !defined(SWT_NO_LEGACY_TEST_DISCOVERY)
  static const char typeMetadataSectionBegin = 0;
- static const char& typeMetadataSectionEnd = testContentSectionBegin;
+ static const char& typeMetadataSectionEnd = typeMetadataSectionBegin;
+ #endif
  #endif
 ```
 

Package.swift

@@ -89,10 +89,7 @@ let package = Package(
         "_Testing_CoreGraphics",
         "_Testing_Foundation",
       ],
-      swiftSettings: .packageSettings + [
-        // For testing test content section discovery only
-        .enableExperimentalFeature("SymbolLinkageMarkers"),
-      ]
+      swiftSettings: .packageSettings
     ),
 
     .macro(
@@ -205,6 +202,11 @@ extension Array where Element == PackageDescription.SwiftSetting {
       .enableExperimentalFeature("AccessLevelOnImport"),
       .enableUpcomingFeature("InternalImportsByDefault"),
 
+      // This setting is enabled in the package, but not in the toolchain build
+      // (via CMake). Enabling it is dependent on acceptance of the @section
+      // proposal via Swift Evolution.
+      .enableExperimentalFeature("SymbolLinkageMarkers"),
+
       // When building as a package, the macro plugin always builds as an
       // executable rather than a library.
       .define("SWT_NO_LIBRARY_MACRO_PLUGINS"),

Sources/Testing/ExitTests/ExitTest.swift

@@ -296,12 +296,14 @@ extension ExitTest {
       }
     }
 
+#if !SWT_NO_LEGACY_TEST_DISCOVERY
     // Call the legacy lookup function that discovers tests embedded in types.
     for record in Self.allTypeMetadataBasedTestContentRecords() {
       if let exitTest = record.load(withHint: id) {
         return exitTest
       }
     }
+#endif
 
     return nil
   }

Sources/Testing/Test+Discovery+Legacy.swift

@@ -8,6 +8,7 @@
 // See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 //
 
+#if !SWT_NO_LEGACY_TEST_DISCOVERY
 @_spi(Experimental) @_spi(ForToolsIntegrationOnly) internal import _TestDiscovery
 
 /// A shadow declaration of `_TestDiscovery.TestContentRecordContainer` that
@@ -41,3 +42,4 @@ open class __TestContentRecordContainer: TestContentRecordContainer {
 
 @available(*, unavailable)
 extension __TestContentRecordContainer: Sendable {}
+#endif

Sources/Testing/Test+Discovery.swift

@@ -65,6 +65,7 @@ extension Test {
       // the legacy and new mechanisms, but we can set an environment variable
       // to explicitly select one or the other. When we remove legacy support,
       // we can also remove this enumeration and environment variable check.
+#if !SWT_NO_LEGACY_TEST_DISCOVERY
       let (useNewMode, useLegacyMode) = switch Environment.flag(named: "SWT_USE_LEGACY_TEST_DISCOVERY") {
       case .none:
         (true, true)
@@ -73,6 +74,9 @@ extension Test {
       case .some(false):
         (true, false)
       }
+#else
+      let useNewMode = true
+#endif
 
       // Walk all test content and gather generator functions, then call them in
       // a task group and collate their results.
@@ -86,6 +90,7 @@ extension Test {
         }
       }
 
+#if !SWT_NO_LEGACY_TEST_DISCOVERY
       // Perform legacy test discovery if needed.
       if useLegacyMode && result.isEmpty {
         let generators = Generator.allTypeMetadataBasedTestContentRecords().lazy.compactMap { $0.load() }
@@ -96,6 +101,7 @@ extension Test {
           result = await taskGroup.reduce(into: result) { $0.insert($1) }
         }
       }
+#endif
 
       return result
     }

Sources/TestingMacros/ConditionMacro.swift

@@ -11,6 +11,10 @@
 public import SwiftSyntax
 public import SwiftSyntaxMacros
 
+#if !hasFeature(SymbolLinkageMarkers) && SWT_NO_LEGACY_TEST_DISCOVERY
+#error("Platform-specific misconfiguration: either SymbolLinkageMarkers or legacy test discovery is required to expand #expect(exitsWith:)")
+#endif
+
 /// A protocol containing the common implementation for the expansions of the
 /// `#expect()` and `#require()` macros.
 ///
@@ -452,42 +456,59 @@ extension ExitTestConditionMacro {
 
     // Create a local type that can be discovered at runtime and which contains
     // the exit test body.
-    let className = context.makeUniqueName("__🟡$")
-    let testContentRecordDecl = makeTestContentRecordDecl(
-      named: .identifier("testContentRecord"),
-      in: TypeSyntax(IdentifierTypeSyntax(name: className)),
-      ofKind: .exitTest,
-      accessingWith: .identifier("accessor")
-    )
-
-    decls.append(
-      """
-      @available(*, deprecated, message: "This type is an implementation detail of the testing library. Do not use it directly.")
-      final class \(className): Testing.__TestContentRecordContainer {
-        private nonisolated static let accessor: Testing.__TestContentRecordAccessor = { outValue, type, hint in
-          Testing.ExitTest.__store(
-            \(exitTestIDExpr),
-            \(bodyThunkName),
-            into: outValue,
-            asTypeAt: type,
-            withHintAt: hint
-          )
-        }
-
-        \(testContentRecordDecl)
+    let enumName = context.makeUniqueName("")
+    do {
+      // Create the test content record.
+      let testContentRecordDecl = makeTestContentRecordDecl(
+        named: .identifier("testContentRecord"),
+        in: TypeSyntax(IdentifierTypeSyntax(name: enumName)),
+        ofKind: .exitTest,
+        accessingWith: .identifier("accessor")
+      )
 
+      // Create another local type for legacy test discovery.
+      var recordDecl: DeclSyntax?
+#if !SWT_NO_LEGACY_TEST_DISCOVERY
+      let className = context.makeUniqueName("__🟡$")
+      recordDecl = """
+      private final class \(className): Testing.__TestContentRecordContainer {
         override nonisolated class var __testContentRecord: Testing.__TestContentRecord {
-          testContentRecord
+          \(enumName).testContentRecord
         }
       }
       """
-    )
+#endif
+
+      decls.append(
+        """
+        @available(*, deprecated, message: "This type is an implementation detail of the testing library. Do not use it directly.")
+        enum \(enumName) {
+          private nonisolated static let accessor: Testing.__TestContentRecordAccessor = { outValue, type, hint in
+            Testing.ExitTest.__store(
+              \(exitTestIDExpr),
+              \(bodyThunkName),
+              into: outValue,
+              asTypeAt: type,
+              withHintAt: hint
+            )
+          }
+
+          \(testContentRecordDecl)
+
+          \(recordDecl)
+        }
+        """
+      )
+    }
 
     arguments[trailingClosureIndex].expression = ExprSyntax(
       ClosureExprSyntax {
         for decl in decls {
-          CodeBlockItemSyntax(item: .decl(decl))
-            .with(\.trailingTrivia, .newline)
+          CodeBlockItemSyntax(
+            leadingTrivia: .newline,
+            item: .decl(decl),
+            trailingTrivia: .newline
+          )
         }
       }
     )

Sources/TestingMacros/SuiteDeclarationMacro.swift

@@ -11,6 +11,10 @@
 public import SwiftSyntax
 public import SwiftSyntaxMacros
 
+#if !hasFeature(SymbolLinkageMarkers) && SWT_NO_LEGACY_TEST_DISCOVERY
+#error("Platform-specific misconfiguration: either SymbolLinkageMarkers or legacy test discovery is required to expand @Suite")
+#endif
+
 /// A type describing the expansion of the `@Suite` attribute macro.
 ///
 /// This type is used to implement the `@Suite` attribute macro. Do not use it
@@ -160,6 +164,7 @@ public struct SuiteDeclarationMacro: MemberMacro, PeerMacro, Sendable {
       )
     )
 
+#if !SWT_NO_LEGACY_TEST_DISCOVERY
     // Emit a type that contains a reference to the test content record.
     let className = context.makeUniqueName("__🟡$")
     result.append(
@@ -172,6 +177,7 @@ public struct SuiteDeclarationMacro: MemberMacro, PeerMacro, Sendable {
       }
       """
     )
+#endif
 
     return result
   }

Sources/TestingMacros/Support/TestContentGeneration.swift

@@ -62,6 +62,18 @@ func makeTestContentRecordDecl(named name: TokenSyntax, in typeName: TypeSyntax?
   }
 
   return """
+  #if hasFeature(SymbolLinkageMarkers)
+  #if os(macOS) || os(iOS) || os(watchOS) || os(tvOS) || os(visionOS)
+  @_section("__DATA_CONST,__swift5_tests")
+  #elseif os(Linux) || os(FreeBSD) || os(OpenBSD) || os(Android) || os(WASI)
+  @_section("swift5_tests")
+  #elseif os(Windows)
+  @_section(".sw5test$B")
+  #else
+  @__testing(warning: "Platform-specific implementation missing: test content section name unavailable")
+  #endif
+  @_used
+  #endif
   @available(*, deprecated, message: "This property is an implementation detail of the testing library. Do not use it directly.")
   private nonisolated \(staticKeyword(for: typeName)) let \(name): Testing.__TestContentRecord = (
     \(kindExpr), \(kind.commentRepresentation)

Sources/TestingMacros/TestDeclarationMacro.swift

@@ -11,6 +11,10 @@
 public import SwiftSyntax
 public import SwiftSyntaxMacros
 
+#if !hasFeature(SymbolLinkageMarkers) && SWT_NO_LEGACY_TEST_DISCOVERY
+#error("Platform-specific misconfiguration: either SymbolLinkageMarkers or legacy test discovery is required to expand @Test")
+#endif
+
 /// A type describing the expansion of the `@Test` attribute macro.
 ///
 /// This type is used to implement the `@Test` attribute macro. Do not use it
@@ -188,17 +192,6 @@ public struct TestDeclarationMacro: PeerMacro, Sendable {
     return FunctionParameterClauseSyntax(parameters: parameterList)
   }
 
-  /// The `static` keyword, if `typeName` is not `nil`.
-  ///
-  /// - Parameters:
-  ///   - typeName: The name of the type containing the macro being expanded.
-  ///
-  /// - Returns: A token representing the `static` keyword, or one representing
-  ///   nothing if `typeName` is `nil`.
-  private static func _staticKeyword(for typeName: TypeSyntax?) -> TokenSyntax {
-    (typeName != nil) ? .keyword(.static) : .unknown("")
-  }
-
   /// Create a thunk function with a normalized signature that calls a
   /// developer-supplied test function.
   ///
@@ -356,7 +349,7 @@ public struct TestDeclarationMacro: PeerMacro, Sendable {
     let thunkName = context.makeUniqueName(thunking: functionDecl)
     let thunkDecl: DeclSyntax = """
     @available(*, deprecated, message: "This function is an implementation detail of the testing library. Do not use it directly.")
-    @Sendable private \(_staticKeyword(for: typeName)) func \(thunkName)\(thunkParamsExpr) async throws -> Void {
+    @Sendable private \(staticKeyword(for: typeName)) func \(thunkName)\(thunkParamsExpr) async throws -> Void {
       \(thunkBody)
     }
     """
@@ -496,6 +489,7 @@ public struct TestDeclarationMacro: PeerMacro, Sendable {
       )
     )
 
+#if !SWT_NO_LEGACY_TEST_DISCOVERY
     // Emit a type that contains a reference to the test content record.
     let className = context.makeUniqueName(thunking: functionDecl, withPrefix: "__🟡$")
     result.append(
@@ -508,6 +502,7 @@ public struct TestDeclarationMacro: PeerMacro, Sendable {
       }
       """
     )
+#endif
 
     return result
   }

Sources/_TestDiscovery/SectionBounds.swift

@@ -27,8 +27,10 @@ struct SectionBounds: Sendable {
     /// The test content metadata section.
     case testContent
 
+#if !SWT_NO_LEGACY_TEST_DISCOVERY
     /// The type metadata section.
     case typeMetadata
+#endif
   }
 
   /// All section bounds of the given kind found in the current process.
@@ -60,8 +62,10 @@ extension SectionBounds.Kind {
     switch self {
     case .testContent:
       ("__DATA_CONST", "__swift5_tests")
+#if !SWT_NO_LEGACY_TEST_DISCOVERY
     case .typeMetadata:
       ("__TEXT", "__swift5_types")
+#endif
     }
   }
 }
@@ -186,8 +190,10 @@ private func _sectionBounds(_ kind: SectionBounds.Kind) -> [SectionBounds] {
       let range = switch context.pointee.kind {
       case .testContent:
         sections.swift5_tests
+#if !SWT_NO_LEGACY_TEST_DISCOVERY
       case .typeMetadata:
         sections.swift5_type_metadata
+#endif
       }
       let start = UnsafeRawPointer(bitPattern: range.start)
       let size = Int(clamping: range.length)
@@ -276,8 +282,10 @@ private func _sectionBounds(_ kind: SectionBounds.Kind) -> some Sequence<Section
   let sectionName = switch kind {
   case .testContent:
     ".sw5test"
+#if !SWT_NO_LEGACY_TEST_DISCOVERY
   case .typeMetadata:
     ".sw5tymd"
+#endif
   }
   return HMODULE.all.lazy.compactMap { _findSection(named: sectionName, in: $0) }
 }

Sources/_TestDiscovery/TestContentRecord.swift

@@ -244,6 +244,7 @@ extension DiscoverableAsTestContent where Self: ~Copyable {
   }
 }
 
+#if !SWT_NO_LEGACY_TEST_DISCOVERY
 // MARK: - Legacy test content discovery
 
 private import _TestingInternals
@@ -344,3 +345,4 @@ extension DiscoverableAsTestContent where Self: ~Copyable {
     return AnySequence(result)
   }
 }
+#endif