Retain '@_dynamicReplacement' members. Closes #874

.swiftlint.yml

@@ -36,3 +36,4 @@ disabled_rules:
   - non_optional_string_data_conversion # https://github.com/realm/SwiftLint/issues/5263#issuecomment-2115182747
   - balanced_xctest_lifecycle
   - todo
+  - for_where

CHANGELOG.md

@@ -12,6 +12,7 @@
 
 - Unused parameter warnings are suppressed in `@available(*, unavailable)` functions.
 - Fix handling of Xcode projects with single and double quotes in their path and scheme names.
+- `@_dynamicReplacement` members are now retained.
 
 ## 3.0.3 (2025-03-15)
 

Sources/BUILD.bazel

@@ -61,7 +61,7 @@ swift_library(
         "SourceGraph/Mutators/CodingKeyEnumReferenceBuilder.swift",
         "SourceGraph/Mutators/ComplexPropertyAccessorReferenceBuilder.swift",
         "SourceGraph/Mutators/DefaultConstructorReferenceBuilder.swift",
-        "SourceGraph/Mutators/DynamicMemberLookupReferenceBuilder.swift",
+        "SourceGraph/Mutators/DynamicMemberRetainer.swift",
         "SourceGraph/Mutators/EntryPointAttributeRetainer.swift",
         "SourceGraph/Mutators/EnumCaseReferenceBuilder.swift",
         "SourceGraph/Mutators/ExtensionReferenceBuilder.swift",

Sources/SourceGraph/Mutators/DynamicMemberLookupReferenceBuilder.swift → Sources/SourceGraph/Mutators/DynamicMemberRetainer.swift

@@ -2,7 +2,7 @@ import Configuration
 import Foundation
 import Shared
 
-final class DynamicMemberLookupReferenceBuilder: SourceGraphMutator {
+final class DynamicMemberRetainer: SourceGraphMutator {
     private let graph: SourceGraph
 
     required init(graph: SourceGraph, configuration _: Configuration, swiftVersion _: SwiftVersion) {
@@ -15,5 +15,11 @@ final class DynamicMemberLookupReferenceBuilder: SourceGraphMutator {
                 graph.markRetained(decl)
             }
         }
+
+        for decl in graph.declarations(ofKinds: [.functionSubscript, .varInstance, .functionMethodInstance]) {
+            if decl.attributes.contains("_dynamicReplacement") {
+                graph.markRetained(decl)
+            }
+        }
     }
 }

Sources/SourceGraph/SourceGraphMutatorRunner.swift

@@ -27,10 +27,10 @@ public final class SourceGraphMutatorRunner {
         ExternalTypeProtocolConformanceReferenceRemover.self,
         ComplexPropertyAccessorReferenceBuilder.self,
         EnumCaseReferenceBuilder.self,
-        DynamicMemberLookupReferenceBuilder.self,
         DefaultConstructorReferenceBuilder.self,
         StructImplicitInitializerReferenceBuilder.self,
 
+        DynamicMemberRetainer.self,
         UnusedParameterRetainer.self,
         AssetReferenceRetainer.self,
         EntryPointAttributeRetainer.self,

Tests/Fixtures/Sources/RetentionFixtures/testRetainsDynamicReplacement.swift

@@ -0,0 +1,26 @@
+struct FixtureStruct8 {
+    dynamic static func originalStaticMethod() {}
+    dynamic func originalMethod() {}
+    dynamic var originalProperty: Int { 0 }
+    dynamic subscript(original index: Int) -> Int { 0}
+}
+
+extension FixtureStruct8 {
+    @_dynamicReplacement(for: originalMethod)
+    func replacementMethod() {}
+
+    @_dynamicReplacement(for: originalProperty)
+    var replacementProperty: Int { 0 }
+
+    @_dynamicReplacement(for: subscript(original:))
+    subscript(replacement index: Int) -> Int { 0}
+}
+
+public struct FixtureStruct8Retainer {
+    public func retain() {
+        let strct = FixtureStruct8()
+        strct.originalMethod()
+        _ = strct.originalProperty
+        _ = strct[original: 0]
+    }
+}

Tests/PeripheryTests/RetentionTest.swift

@@ -1089,6 +1089,55 @@ final class RetentionTest: FixtureSourceGraphTestCase {
         }
     }
 
+    func testMainActorAnnotation() {
+        analyze(retainPublic: true) {
+            assertReferenced(.class("FixtureClass132")) {
+                self.assertReferenced(.functionConstructor("init(value:)"))
+            }
+            assertReferenced(.class("FixtureClass133"))
+        }
+    }
+
+    // https://github.com/apple/swift/issues/64686
+    // https://github.com/peripheryapp/periphery/issues/264
+    func testSelfReferencedConstructor() {
+        analyze(retainPublic: true) {
+            assertReferenced(.struct("FixtureStruct3")) {
+                self.assertReferenced(.functionConstructor("init(value:)"))
+            }
+            assertReferenced(.struct("FixtureStruct4")) {
+                self.assertReferenced(.functionConstructor("init(value:)"))
+            }
+            assertReferenced(.struct("FixtureStruct5")) {
+                self.assertNotReferenced(.functionConstructor("init(value:)"))
+            }
+        }
+    }
+
+    // https://github.com/apple/swift/issues/56541
+    func testStaticMemberUsedAsSubscriptKey() {
+        analyze(retainPublic: true) {
+            assertReferenced(.enum("FixtureEnum128")) {
+                self.assertReferenced(.varStatic("someVar"))
+            }
+        }
+    }
+
+    func testRetainsDynamicReplacement() {
+        analyze(retainPublic: true) {
+            assertReferenced(.struct("FixtureStruct8")) {
+                self.assertReferenced(.functionMethodInstance("originalMethod()"))
+                self.assertReferenced(.functionMethodInstance("replacementMethod()"))
+
+                self.assertReferenced(.varInstance("originalProperty"))
+                self.assertReferenced(.varInstance("replacementProperty"))
+
+                self.assertReferenced(.functionSubscript("subscript(original:)"))
+                self.assertReferenced(.functionSubscript("subscript(replacement:)"))
+            }
+        }
+    }
+
     // MARK: - Swift Testing
 
     #if canImport(Testing)
@@ -1613,40 +1662,6 @@ final class RetentionTest: FixtureSourceGraphTestCase {
         }
     }
 
-    func testMainActorAnnotation() {
-        analyze(retainPublic: true) {
-            assertReferenced(.class("FixtureClass132")) {
-                self.assertReferenced(.functionConstructor("init(value:)"))
-            }
-            assertReferenced(.class("FixtureClass133"))
-        }
-    }
-
-    // https://github.com/apple/swift/issues/64686
-    // https://github.com/peripheryapp/periphery/issues/264
-    func testSelfReferencedConstructor() {
-        analyze(retainPublic: true) {
-            assertReferenced(.struct("FixtureStruct3")) {
-                self.assertReferenced(.functionConstructor("init(value:)"))
-            }
-            assertReferenced(.struct("FixtureStruct4")) {
-                self.assertReferenced(.functionConstructor("init(value:)"))
-            }
-            assertReferenced(.struct("FixtureStruct5")) {
-                self.assertNotReferenced(.functionConstructor("init(value:)"))
-            }
-        }
-    }
-
-    // https://github.com/apple/swift/issues/56541
-    func testStaticMemberUsedAsSubscriptKey() {
-        analyze(retainPublic: true) {
-            assertReferenced(.enum("FixtureEnum128")) {
-                self.assertReferenced(.varStatic("someVar"))
-            }
-        }
-    }
-
     // MARK: - Known Failures
 
     // https://github.com/apple/swift/issues/56165