Revised for implicit internal: Add redundant internal and fileprivate analysis to go alongside redundant public analysis

.github/workflows/test.yml

@@ -122,6 +122,8 @@ jobs:
       run: ${{ env.swift_build }}
     - name: Scan
       run: ${{ env.periphery_scan }} ${{ matrix.baseline && format('--baseline baselines/{0}', matrix.baseline) || '' }}
+    - name: Clean SwiftPM cache
+      run: rm -rf ~/Library/Caches/org.swift.swiftpm
     - name: Test
       run: ${{ env.swift_test }}
   linux:
@@ -169,5 +171,7 @@ jobs:
       run: ${{ env.swift_build }}
     - name: Scan
       run: ${{ env.periphery_scan }} --baseline baselines/linux.json
+    - name: Clean SwiftPM cache
+      run: rm -rf ~/.cache/org.swift.swiftpm
     - name: Test
       run: ${{ env.swift_test }}

README.md

@@ -28,6 +28,8 @@
     - [Enumerations](#enumerations)
     - [Assign-only Properties](#assign-only-properties)
     - [Redundant Public Accessibility](#redundant-public-accessibility)
+    - [Redundant Internal Accessibility](#redundant-internal-accessibility)
+    - [Redundant Fileprivate Accessibility](#redundant-fileprivate-accessibility)
     - [Unused Imports](#unused-imports)
     - [Objective-C](#objective-c)
     - [Codable](#codable)
@@ -292,6 +294,18 @@ Declarations that are marked `public` yet are not referenced from outside their
 
 This analysis can be disabled with `--disable-redundant-public-analysis`.
 
+### Redundant Internal Accessibility
+
+Declarations that are marked `internal` (or are unmarked, since this is Swift's default access level), yet are not referenced outside the file they're defined in are identified as having redundant internal accessibility. In this scenario, the declaration could be marked `private` or `fileprivate`. Reducing the visibility of declarations — encapsulation — helps with code maintainability and can improve compilation performance.
+
+This analysis can be disabled with `--disable-redundant-internal-analysis`.
+
+### Redundant Fileprivate Accessibility
+
+Declarations that are marked `fileprivate` yet are not accessed from other types within the same file are identified as having redundant fileprivate accessibility. If a `fileprivate` declaration is only used within its own type, it should be marked `private` instead. Reducing the visibility of declarations helps with code maintainability and makes access boundaries clearer.
+
+This analysis can be disabled with `--disable-redundant-fileprivate-analysis`.
+
 ### Unused Imports
 
 Periphery can only detect unused imports of targets it has scanned. It cannot detect unused imports of other targets because the Swift source files are unavailable and uses of `@_exported` cannot be observed. `@_exported` is problematic because it changes the public interface of a target such that the declarations exported by the target are no longer necessarily declared by the imported target. For example, the `Foundation` target exports `Dispatch`, among other targets. If any given source file imports `Foundation` and references `DispatchQueue` but no other declarations from `Foundation`, then the `Foundation` import cannot be removed as it would also make the `DispatchQueue` type unavailable. To avoid false positives, therefore, Periphery only detects unused imports of targets it has scanned.

Sources/BUILD.bazel

@@ -78,7 +78,10 @@ swift_library(
         "SourceGraph/Mutators/ProtocolConformanceReferenceBuilder.swift",
         "SourceGraph/Mutators/ProtocolExtensionReferenceBuilder.swift",
         "SourceGraph/Mutators/PubliclyAccessibleRetainer.swift",
+        "SourceGraph/Mutators/RedundantAccessibilityMarkerShared.swift",
         "SourceGraph/Mutators/RedundantExplicitPublicAccessibilityMarker.swift",
+        "SourceGraph/Mutators/RedundantFilePrivateAccessibilityMarker.swift",
+        "SourceGraph/Mutators/RedundantInternalAccessibilityMarker.swift",
         "SourceGraph/Mutators/RedundantProtocolMarker.swift",
         "SourceGraph/Mutators/ResultBuilderRetainer.swift",
         "SourceGraph/Mutators/StringInterpolationAppendInterpolationRetainer.swift",

Sources/Configuration/Configuration.swift

@@ -80,6 +80,15 @@ public final class Configuration {
     @Setting(key: "disable_redundant_public_analysis", defaultValue: false)
     public var disableRedundantPublicAnalysis: Bool
 
+    @Setting(key: "disable_redundant_internal_analysis", defaultValue: false)
+    public var disableRedundantInternalAnalysis: Bool
+
+    @Setting(key: "disable_redundant_fileprivate_analysis", defaultValue: false)
+    public var disableRedundantFilePrivateAnalysis: Bool
+
+    @Setting(key: "show_nested_redundant_accessibility", defaultValue: false)
+    public var showNestedRedundantAccessibility: Bool
+
     @Setting(key: "disable_unused_import_analysis", defaultValue: false)
     public var disableUnusedImportAnalysis: Bool
 
@@ -215,10 +224,11 @@ public final class Configuration {
 
     // MARK: - Private
 
-    lazy var settings: [any AbstractSetting] = [
+    private lazy var settings: [any AbstractSetting] = [
         $project, $schemes, $excludeTargets, $excludeTests, $indexExclude, $reportExclude, $reportInclude, $outputFormat,
         $retainPublic, $noRetainSPI, $retainFiles, $retainAssignOnlyProperties, $retainAssignOnlyPropertyTypes, $retainObjcAccessible,
         $retainObjcAnnotated, $retainUnusedProtocolFuncParams, $retainSwiftUIPreviews, $disableRedundantPublicAnalysis,
+        $disableRedundantInternalAnalysis, $disableRedundantFilePrivateAnalysis, $showNestedRedundantAccessibility,
         $disableUnusedImportAnalysis, $superfluousIgnoreComments, $retainUnusedImportedModules,
         $externalEncodableProtocols, $externalCodableProtocols, $externalTestCaseClasses, $verbose, $quiet, $color,
         $disableUpdateCheck, $strict, $indexStorePath,
@@ -246,7 +256,7 @@ public final class Configuration {
     }
 }
 
-protocol AbstractSetting {
+private protocol AbstractSetting {
     associatedtype Value
 
     var key: String { get }

Sources/Frontend/Commands/ScanCommand.swift

@@ -13,151 +13,160 @@ struct ScanCommand: ParsableCommand {
     )
 
     @Argument(help: "Arguments following '--' will be passed to the underlying build tool, which is either 'swift build' or 'xcodebuild' depending on your project")
-    var buildArguments: [String] = defaultConfiguration.$buildArguments.defaultValue
+    private var buildArguments: [String] = defaultConfiguration.$buildArguments.defaultValue
 
     @Flag(help: "Enable guided setup")
-    var setup: Bool = defaultConfiguration.guidedSetup
+    private var setup: Bool = defaultConfiguration.guidedSetup
 
     @Option(help: "Path to the root directory of your project")
-    var projectRoot: FilePath = projectRootDefault
+    private var projectRoot: FilePath = projectRootDefault
 
     @Option(help: "Path to configuration file. By default Periphery will look for .periphery.yml in the current directory")
-    var config: FilePath?
+    private var config: FilePath?
 
     @Option(help: "Path to your project's .xcodeproj or .xcworkspace")
-    var project: FilePath?
+    private var project: FilePath?
 
     @Option(parsing: .upToNextOption, help: "Schemes to build. All targets built by these schemes will be scanned")
-    var schemes: [String] = defaultConfiguration.$schemes.defaultValue
+    private var schemes: [String] = defaultConfiguration.$schemes.defaultValue
 
     @Option(help: "Output format")
-    var format: OutputFormat = defaultConfiguration.$outputFormat.defaultValue
+    private var format: OutputFormat = defaultConfiguration.$outputFormat.defaultValue
 
     @Flag(help: "Exclude test targets from indexing")
-    var excludeTests: Bool = defaultConfiguration.$excludeTests.defaultValue
+    private var excludeTests: Bool = defaultConfiguration.$excludeTests.defaultValue
 
     @Option(parsing: .upToNextOption, help: "Targets to exclude from indexing")
-    var excludeTargets: [String] = defaultConfiguration.$excludeTargets.defaultValue
+    private var excludeTargets: [String] = defaultConfiguration.$excludeTargets.defaultValue
 
     @Option(parsing: .upToNextOption, help: "Source file globs to exclude from indexing")
-    var indexExclude: [String] = defaultConfiguration.$indexExclude.defaultValue
+    private var indexExclude: [String] = defaultConfiguration.$indexExclude.defaultValue
 
     @Option(parsing: .upToNextOption, help: "Source file globs to exclude from the results. Note that this option is purely cosmetic, these files will still be indexed")
-    var reportExclude: [String] = defaultConfiguration.$reportExclude.defaultValue
+    private var reportExclude: [String] = defaultConfiguration.$reportExclude.defaultValue
 
     @Option(parsing: .upToNextOption, help: "Source file globs to include in the results. This option supersedes '--report-exclude'. Note that this option is purely cosmetic, these files will still be indexed")
-    var reportInclude: [String] = defaultConfiguration.$reportInclude.defaultValue
+    private var reportInclude: [String] = defaultConfiguration.$reportInclude.defaultValue
 
     @Option(parsing: .upToNextOption, help: "Source file globs for which all containing declarations will be retained")
-    var retainFiles: [String] = defaultConfiguration.$retainFiles.defaultValue
+    private var retainFiles: [String] = defaultConfiguration.$retainFiles.defaultValue
 
     @Option(parsing: .upToNextOption, help: "Index store paths. Implies '--skip-build'")
-    var indexStorePath: [FilePath] = defaultConfiguration.$indexStorePath.defaultValue
+    private var indexStorePath: [FilePath] = defaultConfiguration.$indexStorePath.defaultValue
 
     @Flag(help: "Retain all public declarations, recommended for framework/library projects")
-    var retainPublic: Bool = defaultConfiguration.$retainPublic.defaultValue
+    private var retainPublic: Bool = defaultConfiguration.$retainPublic.defaultValue
 
     @Option(parsing: .upToNextOption, help: "Public SPIs (System Programming Interfaces) to check for unused code even when '--retain-public' is enabled")
-    var noRetainSPI: [String] = defaultConfiguration.$noRetainSPI.defaultValue
+    private var noRetainSPI: [String] = defaultConfiguration.$noRetainSPI.defaultValue
 
     @Flag(help: "Disable identification of redundant public accessibility")
-    var disableRedundantPublicAnalysis: Bool = defaultConfiguration.$disableRedundantPublicAnalysis.defaultValue
+    private var disableRedundantPublicAnalysis: Bool = defaultConfiguration.$disableRedundantPublicAnalysis.defaultValue
+
+    @Flag(help: "Disable identification of redundant internal accessibility")
+    private var disableRedundantInternalAnalysis: Bool = defaultConfiguration.$disableRedundantInternalAnalysis.defaultValue
+
+    @Flag(help: "Disable identification of redundant fileprivate accessibility")
+    private var disableRedundantFilePrivateAnalysis: Bool = defaultConfiguration.$disableRedundantFilePrivateAnalysis.defaultValue
+
+    @Flag(help: "Show redundant internal/fileprivate accessibility warnings for nested declarations even when the containing type is already flagged")
+    private var showNestedRedundantAccessibility: Bool = defaultConfiguration.$showNestedRedundantAccessibility.defaultValue
 
     @Flag(help: "Disable identification of unused imports")
-    var disableUnusedImportAnalysis: Bool = defaultConfiguration.$disableUnusedImportAnalysis.defaultValue
+    private var disableUnusedImportAnalysis: Bool = defaultConfiguration.$disableUnusedImportAnalysis.defaultValue
 
     @Flag(inversion: .prefixedNo, help: "Report superfluous ignore comments")
-    var superfluousIgnoreComments: Bool = defaultConfiguration.$superfluousIgnoreComments.defaultValue
+    private var superfluousIgnoreComments: Bool = defaultConfiguration.$superfluousIgnoreComments.defaultValue
 
     @Option(parsing: .upToNextOption, help: "Names of unused imported modules to retain")
-    var retainUnusedImportedModules: [String] = defaultConfiguration.$retainUnusedImportedModules.defaultValue
+    private var retainUnusedImportedModules: [String] = defaultConfiguration.$retainUnusedImportedModules.defaultValue
 
     @Flag(help: "Retain properties that are assigned, but never used")
-    var retainAssignOnlyProperties: Bool = defaultConfiguration.$retainAssignOnlyProperties.defaultValue
+    private var retainAssignOnlyProperties: Bool = defaultConfiguration.$retainAssignOnlyProperties.defaultValue
 
     @Option(parsing: .upToNextOption, help: "Property types to retain if the property is assigned, but never read")
-    var retainAssignOnlyPropertyTypes: [String] = defaultConfiguration.$retainAssignOnlyPropertyTypes.defaultValue
+    private var retainAssignOnlyPropertyTypes: [String] = defaultConfiguration.$retainAssignOnlyPropertyTypes.defaultValue
 
     @Option(parsing: .upToNextOption, help: "Names of external protocols that inherit Encodable. Properties and CodingKey enums of types conforming to these protocols will be retained")
-    var externalEncodableProtocols: [String] = defaultConfiguration.$externalEncodableProtocols.defaultValue
+    private var externalEncodableProtocols: [String] = defaultConfiguration.$externalEncodableProtocols.defaultValue
 
     @Option(parsing: .upToNextOption, help: "Names of external protocols that inherit Codable. Properties and CodingKey enums of types conforming to these protocols will be retained")
-    var externalCodableProtocols: [String] = defaultConfiguration.$externalCodableProtocols.defaultValue
+    private var externalCodableProtocols: [String] = defaultConfiguration.$externalCodableProtocols.defaultValue
 
     @Option(parsing: .upToNextOption, help: "Names of XCTestCase subclasses that reside in external targets")
-    var externalTestCaseClasses: [String] = defaultConfiguration.$externalTestCaseClasses.defaultValue
+    private var externalTestCaseClasses: [String] = defaultConfiguration.$externalTestCaseClasses.defaultValue
 
     @Flag(help: "Retain declarations that are exposed to Objective-C implicitly by inheriting NSObject classes, or explicitly with the @objc and @objcMembers attributes")
-    var retainObjcAccessible: Bool = defaultConfiguration.$retainObjcAccessible.defaultValue
+    private var retainObjcAccessible: Bool = defaultConfiguration.$retainObjcAccessible.defaultValue
 
     @Flag(help: "Retain declarations that are exposed to Objective-C explicitly with the @objc and @objcMembers attributes")
-    var retainObjcAnnotated: Bool = defaultConfiguration.$retainObjcAnnotated.defaultValue
+    private var retainObjcAnnotated: Bool = defaultConfiguration.$retainObjcAnnotated.defaultValue
 
     @Flag(help: "Retain unused protocol function parameters, even if the parameter is unused in all conforming functions")
-    var retainUnusedProtocolFuncParams: Bool = defaultConfiguration.$retainUnusedProtocolFuncParams.defaultValue
+    private var retainUnusedProtocolFuncParams: Bool = defaultConfiguration.$retainUnusedProtocolFuncParams.defaultValue
 
     @Flag(help: "Retain SwiftUI previews")
-    var retainSwiftUIPreviews: Bool = defaultConfiguration.$retainSwiftUIPreviews.defaultValue
+    private var retainSwiftUIPreviews: Bool = defaultConfiguration.$retainSwiftUIPreviews.defaultValue
 
     @Flag(help: "Retain properties on Codable types (including Encodable and Decodable)")
-    var retainCodableProperties: Bool = defaultConfiguration.$retainCodableProperties.defaultValue
+    private var retainCodableProperties: Bool = defaultConfiguration.$retainCodableProperties.defaultValue
 
     @Flag(help: "Retain properties on Encodable types only")
-    var retainEncodableProperties: Bool = defaultConfiguration.$retainEncodableProperties.defaultValue
+    private var retainEncodableProperties: Bool = defaultConfiguration.$retainEncodableProperties.defaultValue
 
     @Flag(help: "Clean existing build artifacts before building")
-    var cleanBuild: Bool = defaultConfiguration.$cleanBuild.defaultValue
+    private var cleanBuild: Bool = defaultConfiguration.$cleanBuild.defaultValue
 
     @Flag(help: "Skip the project build step")
-    var skipBuild: Bool = defaultConfiguration.$skipBuild.defaultValue
+    private var skipBuild: Bool = defaultConfiguration.$skipBuild.defaultValue
 
     @Flag(help: "Skip schemes validation")
-    var skipSchemesValidation: Bool = defaultConfiguration.$skipSchemesValidation.defaultValue
+    private var skipSchemesValidation: Bool = defaultConfiguration.$skipSchemesValidation.defaultValue
 
     @Flag(help: "Output result paths relative to the current directory")
-    var relativeResults: Bool = defaultConfiguration.$relativeResults.defaultValue
+    private var relativeResults: Bool = defaultConfiguration.$relativeResults.defaultValue
 
     @Flag(help: "Exit with non-zero status if any unused code is found")
-    var strict: Bool = defaultConfiguration.$strict.defaultValue
+    private var strict: Bool = defaultConfiguration.$strict.defaultValue
 
     @Flag(help: "Disable checking for updates")
-    var disableUpdateCheck: Bool = defaultConfiguration.$disableUpdateCheck.defaultValue
+    private var disableUpdateCheck: Bool = defaultConfiguration.$disableUpdateCheck.defaultValue
 
     @Flag(help: "Enable verbose logging")
-    var verbose: Bool = defaultConfiguration.$verbose.defaultValue
+    private var verbose: Bool = defaultConfiguration.$verbose.defaultValue
 
     @Flag(help: "Only output results")
-    var quiet: Bool = defaultConfiguration.$quiet.defaultValue
+    private var quiet: Bool = defaultConfiguration.$quiet.defaultValue
 
     @Option(help: "Colored output mode")
-    var color: ColorOption = defaultConfiguration.$color.defaultValue
+    private var color: ColorOption = defaultConfiguration.$color.defaultValue
 
     @Flag(name: .customLong("no-color"), help: .hidden)
-    var noColor: Bool = false
+    private var noColor: Bool = false
 
     @Option(help: "JSON package manifest path (obtained using `swift package describe --type json` or manually)")
-    var jsonPackageManifestPath: FilePath?
+    private var jsonPackageManifestPath: FilePath?
 
     @Option(help: "Baseline file path used to filter results")
-    var baseline: FilePath?
+    private var baseline: FilePath?
 
     @Option(help: "Baseline file path where results are written. Pass the same path to '--baseline' in subsequent scans to exclude the results recorded in the baseline.")
-    var writeBaseline: FilePath?
+    private var writeBaseline: FilePath?
 
     @Option(help: "File path where formatted results are written.")
-    var writeResults: FilePath?
+    private var writeResults: FilePath?
 
     @Option(help: "Project configuration for non-Apple build systems")
-    var genericProjectConfig: FilePath?
+    private var genericProjectConfig: FilePath?
 
     @Flag(help: "Enable Bazel project mode")
-    var bazel: Bool = defaultConfiguration.$bazel.defaultValue
+    private var bazel: Bool = defaultConfiguration.$bazel.defaultValue
 
     @Option(help: "Filter pattern applied to the Bazel top-level targets query")
-    var bazelFilter: String?
+    private var bazelFilter: String?
 
     @Option(help: "Path to a global index store populated by Bazel. If provided, will be used instead of individual module stores.")
-    var bazelIndexStore: FilePath?
+    private var bazelIndexStore: FilePath?
 
     @Flag(help: "Enable Bazel visibility checking")
     var bazelCheckVisibility: Bool = defaultConfiguration.$bazelCheckVisibility.defaultValue
@@ -193,6 +202,9 @@ struct ScanCommand: ParsableCommand {
         configuration.apply(\.$retainUnusedProtocolFuncParams, retainUnusedProtocolFuncParams)
         configuration.apply(\.$retainSwiftUIPreviews, retainSwiftUIPreviews)
         configuration.apply(\.$disableRedundantPublicAnalysis, disableRedundantPublicAnalysis)
+        configuration.apply(\.$disableRedundantInternalAnalysis, disableRedundantInternalAnalysis)
+        configuration.apply(\.$disableRedundantFilePrivateAnalysis, disableRedundantFilePrivateAnalysis)
+        configuration.apply(\.$showNestedRedundantAccessibility, showNestedRedundantAccessibility)
         configuration.apply(\.$disableUnusedImportAnalysis, disableUnusedImportAnalysis)
         configuration.apply(\.$superfluousIgnoreComments, superfluousIgnoreComments)
         configuration.apply(\.$retainUnusedImportedModules, retainUnusedImportedModules)

Sources/Frontend/Project.swift

@@ -6,7 +6,7 @@ import Shared
 import SystemPackage
 
 final class Project {
-    let kind: ProjectKind
+    private let kind: ProjectKind
 
     private let configuration: Configuration
     private let shell: Shell