Fixture-based test coverage for MachOSwiftSection Models/

.swiftpm/xcode/xcshareddata/xcschemes/MachOSwiftSection-Package.xcscheme

@@ -212,6 +212,20 @@
                ReferencedContainer = "container:">
             </BuildableReference>
          </BuildActionEntry>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "baseline-generator"
+               BuildableName = "baseline-generator"
+               BlueprintName = "baseline-generator"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </BuildActionEntry>
       </BuildActionEntries>
    </BuildAction>
    <TestAction
@@ -301,6 +315,26 @@
                ReferencedContainer = "container:">
             </BuildableReference>
          </TestableReference>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "MachOTestingSupportTests"
+               BuildableName = "MachOTestingSupportTests"
+               BlueprintName = "MachOTestingSupportTests"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </TestableReference>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "IntegrationTests"
+               BuildableName = "IntegrationTests"
+               BlueprintName = "IntegrationTests"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </TestableReference>
       </Testables>
    </TestAction>
    <LaunchAction
@@ -313,6 +347,16 @@
       debugDocumentVersioning = "YES"
       debugServiceExtension = "internal"
       allowLocationSimulation = "YES">
+      <BuildableProductRunnable
+         runnableDebuggingMode = "0">
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "baseline-generator"
+            BuildableName = "baseline-generator"
+            BlueprintName = "baseline-generator"
+            ReferencedContainer = "container:">
+         </BuildableReference>
+      </BuildableProductRunnable>
       <MacroExpansion>
          <BuildableReference
             BuildableIdentifier = "primary"
@@ -336,15 +380,16 @@
       savedToolIdentifier = ""
       useCustomWorkingDirectory = "NO"
       debugDocumentVersioning = "YES">
-      <MacroExpansion>
+      <BuildableProductRunnable
+         runnableDebuggingMode = "0">
          <BuildableReference
             BuildableIdentifier = "primary"
-            BlueprintIdentifier = "swift-section"
-            BuildableName = "swift-section"
-            BlueprintName = "swift-section"
+            BlueprintIdentifier = "baseline-generator"
+            BuildableName = "baseline-generator"
+            BlueprintName = "baseline-generator"
             ReferencedContainer = "container:">
          </BuildableReference>
-      </MacroExpansion>
+      </BuildableProductRunnable>
    </ProfileAction>
    <AnalyzeAction
       buildConfiguration = "Debug">

.swiftpm/xcode/xcshareddata/xcschemes/swift-section.xcscheme

@@ -100,6 +100,16 @@
                ReferencedContainer = "container:">
             </BuildableReference>
          </TestableReference>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "IntegrationTests"
+               BuildableName = "IntegrationTests"
+               BlueprintName = "IntegrationTests"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </TestableReference>
       </Testables>
    </TestAction>
    <LaunchAction

CLAUDE.md

@@ -112,6 +112,48 @@ Tests use `MACHO_SWIFT_SECTION_SILENT_TEST=1` to suppress verbose output.
 
 Tests read Mach-O files from Xcode frameworks and dyld shared cache for real-world validation.
 
+## Fixture-Based Test Coverage (MachOSwiftSection)
+
+`MachOSwiftSection/Models/` is exhaustively covered by `Tests/MachOSwiftSectionTests/Fixtures/`. Suites mirror the source directory and assert one of:
+
+- **Cross-reader equality** across MachOFile/MachOImage/InProcess + their ReadingContext counterparts (via `acrossAllReaders` / `acrossAllContexts` helpers), plus per-method ABI literal values from `__Baseline__/*Baseline.swift` — this is the standard depth.
+- **InProcess single-reader equality** plus per-method ABI literal values (via `usingInProcessOnly` helper). Used for runtime-allocated metadata types (MetatypeMetadata, TupleTypeMetadata, etc.) that have no Mach-O section presence.
+- **Sentinel allowlist** with typed `SentinelReason` (in `CoverageAllowlistEntries.swift`). Used for:
+  - `pureDataUtility`: pure raw-value enums / flag bitfields with no behavior to test (tests would just be tautologies)
+  - `runtimeOnly`: types impossible to construct stably from tests (e.g., `swift_allocBox`-allocated `GenericBoxHeapMetadata`)
+  - `needsFixtureExtension`: residual entries deferred by toolchain limits (e.g., `MethodDefaultOverrideTable` requires the not-yet-shipped CoroutineAccessors ABI; canonical-specialized-metadata records need the `-prespecialize-generic-metadata` frontend flag)
+
+`MachOSwiftSectionCoverageInvariantTests` enforces four invariants:
+1. Every public method in `Sources/MachOSwiftSection/Models/` has a registered test (or allowlist entry)
+2. Every registered test name maps to an actual public method
+3. Sentinel-tagged keys' Suites must actually have sentinel behavior (no `acrossAllReaders` / `inProcessContext` references)
+4. Sentinel-behavior Suites must be tagged in the allowlist (no silent sentinels)
+
+`SuiteBehaviorScanner` (in `MachOFixtureSupport`) classifies each `@Test func` body by substring presence of `acrossAllReaders` / `acrossAllContexts` / `machOFile` / `machOImage` / `fileContext` / `imageContext` (cross-reader real test) or `usingInProcessOnly` / `inProcessContext` (InProcess-only real test). Helper-call indirection within the same Suite class is recognized via class-scope inheritance.
+
+To add a new public method:
+
+1. Add the method.
+2. Run `swift test --filter MachOSwiftSectionCoverageInvariantTests` to see which Suite needs updating.
+3. Add a `@Test` to that Suite, using `acrossAllReaders` for fixture-bound types or `usingInProcessOnly` for runtime-only metadata.
+4. Append the member name to `registeredTestMethodNames`.
+5. Run `swift package --allow-writing-to-package-directory regen-baselines --suite <Name>` to regenerate the baseline.
+6. Re-run the affected Suite.
+
+To regenerate all baselines after fixture rebuild or toolchain upgrade:
+
+```bash
+xcodebuild -project Tests/Projects/SymbolTests/SymbolTests.xcodeproj -scheme SymbolTestsCore -configuration Release build
+swift package --allow-writing-to-package-directory regen-baselines
+git diff Tests/MachOSwiftSectionTests/Fixtures/__Baseline__/  # review drift
+```
+
+The `regen-baselines` command is provided by the `RegenerateBaselinesPlugin`
+SwiftPM command plugin (`Plugins/RegenerateBaselinesPlugin/`). It builds and
+invokes the `baseline-generator` executable target. From Xcode you can also
+right-click the package → "Regenerate MachOSwiftSection fixture-test ABI
+baselines.".
+
 ## Work In Progress
 
 ### GenericSpecializer (feature/generic-specializer branch)

Package.swift

@@ -138,7 +138,7 @@ var dependencies: [Package.Dependency] = [
     .package(url: "https://github.com/p-x9/swift-fileio.git", from: "0.9.0"),
     .package(url: "https://github.com/Mx-Iris/FrameworkToolbox", from: "0.4.0"),
 
-    .package(url: "https://github.com/MxIris-Library-Forks/swift-memberwise-init-macro", from: "0.5.3-fork"),
+    .package(url: "https://github.com/gohanlon/swift-memberwise-init-macro", from: "0.6.0"),
     .package(url: "https://github.com/Mx-Iris/SourceKitD", from: "0.1.0"),
     .package(url: "https://github.com/christophhagen/BinaryCodable", from: "3.1.0"),
 
@@ -483,6 +483,38 @@ extension Target {
         ]
     )
 
+    static let baseline_generator = Target.executableTarget(
+        name: "baseline-generator",
+        dependencies: [
+            .target(.MachOFixtureSupport),
+            .product(name: "ArgumentParser", package: "swift-argument-parser"),
+        ],
+        swiftSettings: testSettings
+    )
+
+    // MARK: - Plugins
+
+    /// `swift package regen-baselines` — regenerates the auto-generated
+    /// `__Baseline__/<File>Baseline.swift` files consumed by the fixture-based
+    /// test coverage suites. Replaces the legacy `Scripts/regen-baselines.sh`.
+    static let RegenerateBaselinesPlugin = Target.plugin(
+        name: "RegenerateBaselinesPlugin",
+        capability: .command(
+            intent: .custom(
+                verb: "regen-baselines",
+                description: "Regenerate MachOSwiftSection fixture-test ABI baselines."
+            ),
+            permissions: [
+                .writeToPackageDirectory(
+                    reason: "Writes regenerated baselines under Tests/MachOSwiftSectionTests/Fixtures/__Baseline__/."
+                )
+            ]
+        ),
+        dependencies: [
+            .target(.baseline_generator),
+        ]
+    )
+
     // MARK: - Macros
 
     static let MachOMacros = Target.macro(
@@ -497,19 +529,45 @@ extension Target {
 
     // MARK: - Testing
 
-    static let MachOTestingSupport = Target.target(
-        name: "MachOTestingSupport",
+    /// Fixture-loading helpers, baseline generators, coverage scanners, and
+    /// non-Testing-dependent code. Importable from non-test targets (e.g.
+    /// `baseline-generator`) without dragging in `Testing.framework`.
+    static let MachOFixtureSupport = Target.target(
+        name: "MachOFixtureSupport",
         dependencies: [
             .product(.MachOKit),
             .target(.MachOExtensions),
+            .target(.MachOFoundation),
+            .target(.MachOReading),
+            .target(.MachOResolving),
+            .target(.MachOSwiftSectionC),
             .target(.SwiftDump),
             .target(.SwiftInterface),
             .target(.MachOTestingSupportC),
-            .product(name: "SnapshotTesting", package: "swift-snapshot-testing"),
+            .product(.Demangling),
+            .product(.SwiftSyntax),
+            .product(.SwiftParser),
+            .product(.SwiftSyntaxBuilder),
         ],
         swiftSettings: testSettings
     )
-
+
+    /// `swift-testing` base classes (`MachOFileTests`, `MachOImageTests`,
+    /// `DyldCacheTests`, `XcodeMachOFileTests`, `MachOSwiftSectionFixtureTests`).
+    /// Splitting this out from `MachOFixtureSupport` keeps `Testing.framework`
+    /// out of the link line for non-test targets.
+    static let MachOTestingSupport = Target.target(
+        name: "MachOTestingSupport",
+        dependencies: [
+            .product(.MachOKit),
+            .target(.MachOFoundation),
+            .target(.MachOReading),
+            .target(.MachOResolving),
+            .target(.MachOFixtureSupport),
+        ],
+        swiftSettings: testSettings
+    )
+
     static let MachOTestingSupportC = Target.target(
         name: "MachOTestingSupportC",
         dependencies: [
@@ -522,6 +580,7 @@ extension Target {
         dependencies: [
             .target(.MachOSymbols),
             .target(.MachOTestingSupport),
+            .target(.MachOFixtureSupport),
         ],
         swiftSettings: testSettings
     )
@@ -531,6 +590,7 @@ extension Target {
         dependencies: [
             .target(.MachOSwiftSection),
             .target(.MachOTestingSupport),
+            .target(.MachOFixtureSupport),
             .target(.SwiftDump),
         ],
         swiftSettings: testSettings
@@ -541,6 +601,7 @@ extension Target {
         dependencies: [
             .target(.MachOSwiftSection),
             .target(.MachOTestingSupport),
+            .target(.MachOFixtureSupport),
             .target(.SwiftInspection),
         ],
         swiftSettings: testSettings
@@ -551,6 +612,7 @@ extension Target {
         dependencies: [
             .target(.SwiftDump),
             .target(.MachOTestingSupport),
+            .target(.MachOFixtureSupport),
             .product(.MachOObjCSection),
             .product(name: "SnapshotTesting", package: "swift-snapshot-testing"),
         ],
@@ -562,6 +624,7 @@ extension Target {
         dependencies: [
             .target(.TypeIndexing),
             .target(.MachOTestingSupport),
+            .target(.MachOFixtureSupport),
         ],
         swiftSettings: testSettings
     )
@@ -571,10 +634,51 @@ extension Target {
         dependencies: [
             .target(.SwiftInterface),
             .target(.MachOTestingSupport),
+            .target(.MachOFixtureSupport),
             .product(name: "SnapshotTesting", package: "swift-snapshot-testing"),
         ],
         swiftSettings: testSettings
     )
+
+    static let MachOTestingSupportTests = Target.testTarget(
+        name: "MachOTestingSupportTests",
+        dependencies: [
+            .target(.MachOTestingSupport),
+            .target(.MachOFixtureSupport),
+        ],
+        exclude: [
+            "Coverage/Fixtures/SampleSource.swift.txt",
+            "Coverage/Fixtures/SuiteSampleSource.swift.txt",
+        ],
+        swiftSettings: testSettings
+    )
+
+    static let IntegrationTests = Target.testTarget(
+        name: "IntegrationTests",
+        dependencies: [
+            .target(.MachOExtensions),
+            .target(.MachOCaches),
+            .target(.MachOReading),
+            .target(.MachOResolving),
+            .target(.MachOSymbols),
+            .target(.MachOPointers),
+            .target(.MachOSymbolPointers),
+            .target(.MachOFoundation),
+            .target(.MachOSwiftSection),
+            .target(.SwiftInspection),
+            .target(.SwiftDump),
+            .target(.SwiftInterface),
+            .target(.TypeIndexing),
+            .target(.MachOTestingSupport),
+            .target(.MachOFixtureSupport),
+            .product(.MachOKit),
+            .product(.MachOObjCSection),
+            .product(.Demangling),
+            .product(.Semantic),
+            .product(name: "Dependencies", package: "swift-dependencies"),
+        ],
+        swiftSettings: testSettings
+    )
 }
 
 let package = Package(
@@ -607,11 +711,16 @@ let package = Package(
         .SwiftInterface,
         .TypeIndexing,
         .MachOMacros,
+        .MachOFixtureSupport,
         .MachOTestingSupport,
         .MachOTestingSupportC,
 
         // Executable
         .swift_section,
+        .baseline_generator,
+
+        // Plugins
+        .RegenerateBaselinesPlugin,
 
         // Testing
         .MachOSymbolsTests,
@@ -620,6 +729,8 @@ let package = Package(
         .SwiftDumpTests,
         .TypeIndexingTests,
         .SwiftInterfaceTests,
+        .MachOTestingSupportTests,
+        .IntegrationTests,
     ]
 )