[DO NOT MERGE] Remove legacy test content discovery.

Documentation/Porting.md

@@ -148,10 +148,6 @@ 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()
@@ -193,7 +189,7 @@ to load that information:
 ```
 
 You will also need to update the `makeTestContentRecordDecl()` function in the
-`TestingMacros` target to emit the correct `@_section` attribute for your
+`TestingMacros` target to emit the correct `@section` attribute for your
 platform. If your platform uses the ELF image format and supports the
 `dl_iterate_phdr()` function, add it to the existing `#elseif os(Linux) || ...`
 case. Otherwise, add a new case for your platform:
@@ -203,7 +199,7 @@ case. Otherwise, add a new case for your platform:
 +++ b/Sources/TestingMacros/Support/TestContentGeneration.swift
    // ...
 +  #elseif os(Classic)
-+  @_section(".rsrc,swft,__swift5_tests")
++  @section(".rsrc,swft,__swift5_tests")
    #else
    @__testing(warning: "Platform-specific implementation missing: test content section name unavailable")
    #endif
@@ -214,14 +210,18 @@ directly into test authors' test targets, so you will not be able to use
 compiler conditionals defined in the Swift Testing package (including those that
 start with `"SWT_"`).
 
+> [!NOTE]
+> We are not using `objectFormat()` yet to maintain compatibility with the Swift
+> 6.2 toolchain. We will migrate to `objectFormat()` when we drop Swift 6.2
+> toolchain support (presumably after Swift 6.3 ships).
+
 ## Runtime test discovery with static linkage
 
 If your platform does not support dynamic linking and loading, you will need to
 use static linkage instead. Define the `"SWT_NO_DYNAMIC_LINKING"` compiler
 conditional for your platform in both `Package.swift` and
-`CompilerSettings.cmake`, then define the symbols `_testContentSectionBegin`,
-`_testContentSectionEnd`, `_typeMetadataSectionBegin`, and
-`_typeMetadataSectionEnd` in `SectionBounds.swift`:
+`CompilerSettings.cmake`, then define the symbols `_testContentSectionBegin` and
+`_testContentSectionEnd` in `SectionBounds.swift`:
 
 ```diff
 --- a/Sources/_TestDiscovery/SectionBounds.swift
@@ -230,18 +230,10 @@ conditional for your platform in both `Package.swift` and
 +#elseif os(Classic)
 +@_silgen_name(raw: "...") private nonisolated(unsafe) var _testContentSectionBegin: _SectionBound
 +@_silgen_name(raw: "...") private nonisolated(unsafe) var _testContentSectionEnd: _SectionBound
-+#if !SWT_NO_LEGACY_TEST_DISCOVERY
-+@_silgen_name(raw: "...") private nonisolated(unsafe) var _typeMetadataSectionBegin: _SectionBound
-+@_silgen_name(raw: "...") private nonisolated(unsafe) var _typeMetadataSectionEnd: _SectionBound
-+#endif
  #else
  #warning("Platform-specific implementation missing: Runtime test discovery unavailable (static)")
  private nonisolated(unsafe) let _testContentSectionBegin = UnsafeMutableRawPointer.allocate(byteCount: 1, alignment: 16)
  private nonisolated(unsafe) let _testContentSectionEnd = _testContentSectionBegin
- #if !SWT_NO_LEGACY_TEST_DISCOVERY
- private nonisolated(unsafe) let _typeMetadataSectionBegin = UnsafeMutableRawPointer.allocate(byteCount: 1, alignment: 16)
- private nonisolated(unsafe) let _typeMetadataSectionEnd = _typeMetadataSectionBegin
- #endif
  #endif
  // ...
 ```

Package.swift

@@ -385,11 +385,6 @@ extension Array where Element == PackageDescription.SwiftSetting {
 
       .enableUpcomingFeature("MemberImportVisibility"),
 
-      // 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"),
-
       .enableUpcomingFeature("InferIsolatedConformances"),
 
       // When building as a package, the macro plugin always builds as an
@@ -406,10 +401,15 @@ extension Array where Element == PackageDescription.SwiftSetting {
       .define("SWT_NO_FOUNDATION_FILE_COORDINATION", .whenEmbedded(or: .whenApple(false))),
       .define("SWT_NO_IMAGE_ATTACHMENTS", .whenEmbedded(or: .when(platforms: [.linux, .custom("freebsd"), .openbsd, .wasi, .android]))),
 
-      .define("SWT_NO_LEGACY_TEST_DISCOVERY", .whenEmbedded()),
       .define("SWT_NO_LIBDISPATCH", .whenEmbedded()),
     ]
 
+#if compiler(<6.3)
+    result += [
+      .enableExperimentalFeature("SymbolLinkageMarkers"),
+    ]
+#endif
+
     return result
   }
 
@@ -464,7 +464,6 @@ extension Array where Element == PackageDescription.CXXSetting {
       .define("SWT_NO_PIPES", .whenEmbedded(or: .when(platforms: [.wasi]))),
       .define("SWT_NO_FOUNDATION_FILE_COORDINATION", .whenEmbedded(or: .whenApple(false))),
 
-      .define("SWT_NO_LEGACY_TEST_DISCOVERY", .whenEmbedded()),
       .define("SWT_NO_LIBDISPATCH", .whenEmbedded()),
     ]
 

Sources/Testing/CMakeLists.txt

@@ -99,7 +99,6 @@ add_library(Testing
   Test.swift
   Test+Cancellation.swift
   Test+Discovery.swift
-  Test+Discovery+Legacy.swift
   Test+Macro.swift
   Traits/AttachmentSavingTrait.swift
   Traits/Bug.swift

Sources/Testing/Discovery+Macro.swift

@@ -34,7 +34,7 @@ public typealias __TestContentRecordAccessor = @convention(c) (
 public typealias __TestContentRecord = (
   kind: UInt32,
   reserved1: UInt32,
-  accessor: __TestContentRecordAccessor?,
+  accessor: __TestContentRecordAccessor,
   context: UInt,
   reserved2: UInt
 )

Sources/Testing/ExitTests/ExitTest.swift

@@ -420,15 +420,6 @@ extension ExitTest {
       }
     }
 
-#if !SWT_NO_LEGACY_TEST_DISCOVERY
-    // Call the legacy lookup function that discovers tests embedded in types.
-    for record in Record.allTypeMetadataBasedTestContentRecords() {
-      if let exitTest = record.load(withHint: id)?.makeExitTest() {
-        return exitTest
-      }
-    }
-#endif
-
     return nil
   }
 }

Sources/Testing/Test+Discovery.swift

@@ -63,51 +63,17 @@ extension Test {
       // defective test records.)
       var result = Set<Self>()
 
-      // Figure out which discovery mechanism to use. By default, we'll use both
-      // 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)
-      case .some(true):
-        (false, true)
-      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.
-      if useNewMode {
-        let generators = Generator.allTestContentRecords().lazy.compactMap { $0.load() }
-        await withTaskGroup { taskGroup in
-          for (i, generator) in generators.enumerated() {
-            taskGroup.addTask(name: decorateTaskName("test discovery", withAction: "loading test #\(i)")) {
-              await generator.rawValue()
-            }
-          }
-          result = await taskGroup.reduce(into: result) { $0.insert($1) }
-        }
-      }
-
-#if !SWT_NO_LEGACY_TEST_DISCOVERY
-      // Perform legacy test discovery if needed.
-      if useLegacyMode && result.isEmpty {
-        let generators = Generator.allTypeMetadataBasedTestContentRecords().lazy.compactMap { $0.load() }
-        await withTaskGroup { taskGroup in
-          for (i, generator) in generators.enumerated() {
-            taskGroup.addTask(name: decorateTaskName("type-based test discovery", withAction: "loading test #\(i)")) {
-              await generator.rawValue()
-            }
+      let generators = Generator.allTestContentRecords().lazy.compactMap { $0.load() }
+      await withTaskGroup(of: Self.self) { taskGroup in
+        for (i, generator) in generators.enumerated() {
+          taskGroup.addTask(name: decorateTaskName("test discovery", withAction: "loading test #\(i)")) {
+            await generator.rawValue()
           }
-          result = await taskGroup.reduce(into: result) { $0.insert($1) }
         }
+        result = await taskGroup.reduce(into: result) { $0.insert($1) }
       }
-#endif
 
       return result
     }

Sources/TestingMacros/ConditionMacro.swift

@@ -13,10 +13,6 @@ public import SwiftSyntax
 import SwiftSyntaxBuilder
 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(processExitsWith:)")
-#endif
-
 /// A protocol containing the common implementation for the expansions of the
 /// `#expect()` and `#require()` macros.
 ///
@@ -494,19 +490,6 @@ extension ExitTestConditionMacro {
         accessingWith: .identifier("accessor")
       )
 
-      // Create another local type for legacy test discovery.
-      var recordDecl: DeclSyntax?
-#if !SWT_NO_LEGACY_TEST_DISCOVERY
-      let legacyEnumName = context.makeUniqueName("__🟡$")
-      recordDecl = """
-      enum \(legacyEnumName): Testing.__TestContentRecordContainer {
-        nonisolated static var __testContentRecord: Testing.__TestContentRecord {
-          unsafe \(enumName).testContentRecord
-        }
-      }
-      """
-#endif
-
       decls.append(
         """
         @available(*, deprecated, message: "This type is an implementation detail of the testing library. Do not use it directly.")
@@ -522,8 +505,6 @@ extension ExitTestConditionMacro {
           }
 
           \(testContentRecordDecl)
-
-          \(recordDecl)
         }
         """
       )

Sources/TestingMacros/SuiteDeclarationMacro.swift

@@ -13,10 +13,6 @@ public import SwiftSyntax
 import SwiftSyntaxBuilder
 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
@@ -166,21 +162,6 @@ 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 enumName = context.makeUniqueName("__🟡$")
-    result.append(
-      """
-      @available(*, deprecated, message: "This type is an implementation detail of the testing library. Do not use it directly.")
-      enum \(enumName): Testing.__TestContentRecordContainer {
-        nonisolated static var __testContentRecord: Testing.__TestContentRecord {
-          unsafe \(testContentRecordName)
-        }
-      }
-      """
-    )
-#endif
-
     return result
   }
 }

Sources/TestingMacros/Support/TestContentGeneration.swift

@@ -74,9 +74,22 @@ func makeTestContentRecordDecl(named name: TokenSyntax, in typeName: TypeSyntax?
   )
   """
 
-#if hasFeature(SymbolLinkageMarkers)
+#if compiler(>=6.3)
+  result = """
+  #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.__testing(warning: "Platform-specific implementation missing: test content section name unavailable")
+  #endif
+  @used
+  \(result)
+  """
+#else
   result = """
-  #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)
@@ -87,7 +100,6 @@ func makeTestContentRecordDecl(named name: TokenSyntax, in typeName: TypeSyntax?
   @Testing.__testing(warning: "Platform-specific implementation missing: test content section name unavailable")
   #endif
   @_used
-  #endif
   \(result)
   """
 #endif

Sources/TestingMacros/TestDeclarationMacro.swift

@@ -13,10 +13,6 @@ public import SwiftSyntax
 import SwiftSyntaxBuilder
 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
@@ -493,21 +489,6 @@ public struct TestDeclarationMacro: PeerMacro, Sendable {
       )
     )
 
-#if !SWT_NO_LEGACY_TEST_DISCOVERY
-    // Emit a type that contains a reference to the test content record.
-    let enumName = context.makeUniqueName(thunking: functionDecl, withPrefix: "__🟡$")
-    result.append(
-      """
-      @available(*, deprecated, message: "This type is an implementation detail of the testing library. Do not use it directly.")
-      enum \(enumName): Testing.__TestContentRecordContainer {
-        nonisolated static var __testContentRecord: Testing.__TestContentRecord {
-          unsafe \(testContentRecordName)
-        }
-      }
-      """
-    )
-#endif
-
     return result
   }
 }