Disable fingerprint checking when storage is not available (#3928)

Motivation:

Source compat test failure: https://ci.swift.org/job/swift-PR-source-compat-suite/5701/artifact/swift-source-compat-suite/

```
error: Failed to get source control fingerprint for swift-log remoteSourceControl https://github.com/apple/swift-log.git version 1.4.2 from storage: Error Domain=NSCocoaErrorDomain Code=513 "You don't have permission to save the file "fingerprints" in the folder "security"." UserInfo={NSFilePath=/Users/buildnode/.swiftpm/security/fingerprints, NSUnderlyingError=0x7feaae439370 {Error Domain=NSPOSIXErrorDomain Code=1 "Operation not permitted"}}
error: Error Domain=NSCocoaErrorDomain Code=513 "You don't have permission to save the file "fingerprints" in the folder "security"." UserInfo={NSFilePath=/Users/buildnode/.swiftpm/security/fingerprints, NSUnderlyingError=0x7feaae439370 {Error Domain=NSPOSIXErrorDomain Code=1 "Operation not permitted"}}
```

Modifications:
- Make `PackageFingerprintStorage` optional in `RegistryClient` and `SourceControlPackageContainer`, which would turn off fingerprint read/write and essentially disable the TOFU feature.
- `SwiftTool` will try to create the shared security directory (under which fingerprints are stored), and if it fails (e.g., permission errors) set `PackageFingerprintStorage` to none.
- Don't perform integrity check on fingerprint write. The validation failure will happen on read.

Sources/Commands/SwiftTool.swift

@@ -640,6 +640,20 @@ public class SwiftTool {
             return .none
         }
     }
+
+    private func getSharedSecurityDirectory() throws -> AbsolutePath? {
+        do {
+            let fileSystem = localFileSystem
+            let sharedSecurityDirectory = fileSystem.swiftPMSecurityDirectory
+            if !fileSystem.exists(sharedSecurityDirectory) {
+                try fileSystem.createDirectory(sharedSecurityDirectory, recursive: true)
+            }
+            return sharedSecurityDirectory
+        } catch {
+            self.observabilityScope.emit(warning: "Failed creating shared security directory: \(error)")
+            return .none
+        }
+    }
 
     /// Returns the currently active workspace.
     func getActiveWorkspace() throws -> Workspace {
@@ -649,7 +663,8 @@ public class SwiftTool {
 
         let delegate = ToolWorkspaceDelegate(self.outputStream, logLevel: self.logLevel, observabilityScope: self.observabilityScope)
         let provider = GitRepositoryProvider(processSet: processSet)
-        let sharedCacheDirectory =  try self.getSharedCacheDirectory()
+        let sharedSecurityDirectory = try self.getSharedSecurityDirectory()
+        let sharedCacheDirectory = try self.getSharedCacheDirectory()
         let sharedConfigurationDirectory = try self.getSharedConfigurationDirectory()
         let isXcodeBuildSystemEnabled = self.options.buildSystem == .xcode
         let workspace = try Workspace(
@@ -658,7 +673,7 @@ public class SwiftTool {
                 workingDirectory: buildPath,
                 editsDirectory: self.editsDirectory(),
                 resolvedVersionsFile: self.resolvedVersionsFile(),
-                sharedSecurityDirectory: localFileSystem.swiftPMSecurityDirectory,
+                sharedSecurityDirectory: sharedSecurityDirectory,
                 sharedCacheDirectory: sharedCacheDirectory,
                 sharedConfigurationDirectory: sharedConfigurationDirectory
             ),

Sources/PackageFingerprint/Model.swift

@@ -65,5 +65,4 @@ public typealias PackageFingerprints = [Version: [Fingerprint.Kind: Fingerprint]
 public enum FingerprintCheckingMode: String {
     case strict
     case warn
-    case none
 }

Sources/PackageFingerprint/PackageFingerprintStorage.swift

@@ -46,7 +46,16 @@ public extension PackageFingerprintStorage {
     }
 }
 
-public enum PackageFingerprintStorageError: Error, Equatable {
+public enum PackageFingerprintStorageError: Error, Equatable, CustomStringConvertible {
     case conflict(given: Fingerprint, existing: Fingerprint)
     case notFound
+
+    public var description: String {
+        switch self {
+        case .conflict(let given, let existing):
+            return "Fingerprint \(given) is different from previously recorded value \(existing)"
+        case .notFound:
+            return "Not found"
+        }
+    }
 }

Sources/PackageRegistry/RegistryClient.swift

@@ -100,14 +100,14 @@ public final class RegistryClient {
     private let archiverProvider: (FileSystem) -> Archiver
     private let httpClient: HTTPClient
     private let authorizationProvider: HTTPClientAuthorizationProvider?
-    private let fingerprintStorage: PackageFingerprintStorage
+    private let fingerprintStorage: PackageFingerprintStorage?
     private let fingerprintCheckingMode: FingerprintCheckingMode
     private let jsonDecoder: JSONDecoder
 
     public init(
         configuration: RegistryConfiguration,
         identityResolver: IdentityResolver,
-        fingerprintStorage: PackageFingerprintStorage,
+        fingerprintStorage: PackageFingerprintStorage? = .none,
         fingerprintCheckingMode: FingerprintCheckingMode,
         authorizationProvider: HTTPClientAuthorizationProvider? = .none,
         customHTTPClient: HTTPClient? = .none,
@@ -423,27 +423,23 @@ public final class RegistryClient {
                         throw RegistryError.invalidSourceArchive
                     }
 
-                    self.fingerprintStorage.put(package: package,
-                                                version: version,
-                                                fingerprint: .init(origin: .registry(registry.url), value: checksum),
-                                                observabilityScope: observabilityScope,
-                                                callbackQueue: callbackQueue) { storageResult in
-                        switch storageResult {
-                        case .success:
-                            completion(.success(checksum))
-                        case .failure(PackageFingerprintStorageError.conflict(_, let existing)):
-                            switch self.fingerprintCheckingMode {
-                            case .strict:
-                                completion(.failure(RegistryError.checksumChanged(latest: checksum, previous: existing.value)))
-                            case .warn:
-                                observabilityScope.emit(warning: "The checksum \(checksum) from \(registry.url.absoluteString) does not match previously recorded value \(existing.value) from \(String(describing: existing.origin.url?.absoluteString))")
+                    if let fingerprintStorage = self.fingerprintStorage {
+                        fingerprintStorage.put(package: package,
+                                               version: version,
+                                               fingerprint: .init(origin: .registry(registry.url), value: checksum),
+                                               observabilityScope: observabilityScope,
+                                               callbackQueue: callbackQueue) { storageResult in
+                            switch storageResult {
+                            case .success:
                                 completion(.success(checksum))
-                            case .none:
+                            case .failure(let error):
+                                // Don't throw write errors
+                                observabilityScope.emit(warning: "Failed to save checksum '\(checksum) from \(registry.url) to fingerprints storage: \(error)")
                                 completion(.success(checksum))
                             }
-                        case .failure(let error):
-                            completion(.failure(error))
                         }
+                    } else {
+                        completion(.success(checksum))
                     }
                 } catch {
                     completion(.failure(RegistryError.failedRetrievingReleaseChecksum(error)))
@@ -535,8 +531,6 @@ public final class RegistryClient {
                                     return completion(.failure(RegistryError.invalidChecksum(expected: expectedChecksum, actual: actualChecksum)))
                                 case .warn:
                                     observabilityScope.emit(warning: "The checksum \(actualChecksum) does not match previously recorded value \(expectedChecksum)")
-                                case .none:
-                                    break
                                 }
                             }
 
@@ -567,25 +561,33 @@ public final class RegistryClient {
 
         // We either use a previously recorded checksum, or fetch it from the registry
         func withExpectedChecksum(body: @escaping (Result<String, Error>) -> Void) {
-            self.fingerprintStorage.get(package: package,
-                                        version: version,
-                                        kind: .registry,
-                                        observabilityScope: observabilityScope,
-                                        callbackQueue: callbackQueue) { result in
-                switch result {
-                case .success(let fingerprint):
-                    body(.success(fingerprint.value))
-                case .failure(let error):
-                    if error as? PackageFingerprintStorageError != .notFound {
-                        observabilityScope.emit(error: "Failed to get registry fingerprint for \(package) \(version) from storage: \(error)")
+            if let fingerprintStorage = self.fingerprintStorage {
+                fingerprintStorage.get(package: package,
+                                       version: version,
+                                       kind: .registry,
+                                       observabilityScope: observabilityScope,
+                                       callbackQueue: callbackQueue) { result in
+                    switch result {
+                    case .success(let fingerprint):
+                        body(.success(fingerprint.value))
+                    case .failure(let error):
+                        if error as? PackageFingerprintStorageError != .notFound {
+                            observabilityScope.emit(error: "Failed to get registry fingerprint for \(package) \(version) from storage: \(error)")
+                        }
+                        // Try fetching checksum from registry again no matter which kind of error it is
+                        self.fetchSourceArchiveChecksum(package: package,
+                                                        version: version,
+                                                        observabilityScope: observabilityScope,
+                                                        callbackQueue: callbackQueue,
+                                                        completion: body)
                     }
-                    // Try fetching checksum from registry again no matter which kind of error it is
-                    self.fetchSourceArchiveChecksum(package: package,
-                                                    version: version,
-                                                    observabilityScope: observabilityScope,
-                                                    callbackQueue: callbackQueue,
-                                                    completion: body)
                 }
+            } else {
+                self.fetchSourceArchiveChecksum(package: package,
+                                                version: version,
+                                                observabilityScope: observabilityScope,
+                                                callbackQueue: callbackQueue,
+                                                completion: body)
             }
         }
     }

Sources/Workspace/SourceControlPackageContainer.swift

@@ -55,7 +55,7 @@ internal final class SourceControlPackageContainer: PackageContainer, CustomStri
     private let manifestLoader: ManifestLoaderProtocol
     private let toolsVersionLoader: ToolsVersionLoaderProtocol
     private let currentToolsVersion: ToolsVersion
-    private let fingerprintStorage: PackageFingerprintStorage
+    private let fingerprintStorage: PackageFingerprintStorage?
     private let fingerprintCheckingMode: FingerprintCheckingMode
     private let observabilityScope: ObservabilityScope
 
@@ -79,7 +79,7 @@ internal final class SourceControlPackageContainer: PackageContainer, CustomStri
         manifestLoader: ManifestLoaderProtocol,
         toolsVersionLoader: ToolsVersionLoaderProtocol,
         currentToolsVersion: ToolsVersion,
-        fingerprintStorage: PackageFingerprintStorage,
+        fingerprintStorage: PackageFingerprintStorage?,
         fingerprintCheckingMode: FingerprintCheckingMode,
         observabilityScope: ObservabilityScope
     ) throws {
@@ -150,6 +150,10 @@ internal final class SourceControlPackageContainer: PackageContainer, CustomStri
     }
 
     func checkIntegrity(version: Version, revision: Revision) throws {
+        guard let fingerprintStorage = self.fingerprintStorage else {
+            return
+        }
+
         guard case .remoteSourceControl(let sourceControlURL) = self.package.kind else {
             return
         }
@@ -158,7 +162,7 @@ internal final class SourceControlPackageContainer: PackageContainer, CustomStri
         let fingerprint: Fingerprint
         do {
             fingerprint = try temp_await {
-                self.fingerprintStorage.get(
+                fingerprintStorage.get(
                     package: packageIdentity,
                     version: version,
                     kind: .sourceControl,
@@ -172,7 +176,7 @@ internal final class SourceControlPackageContainer: PackageContainer, CustomStri
             // Write to storage if fingerprint not yet recorded
             do {
                 try temp_await {
-                    self.fingerprintStorage.put(
+                    fingerprintStorage.put(
                         package: packageIdentity,
                         version: version,
                         fingerprint: fingerprint,
@@ -181,16 +185,8 @@ internal final class SourceControlPackageContainer: PackageContainer, CustomStri
                         callback: $0
                     )
                 }
-            } catch PackageFingerprintStorageError.conflict(_, let existing) {
-                let message = "Revision \(revision.identifier) for \(self.package) version \(version) does not match previously recorded value \(existing.value) from \(String(describing: existing.origin.url?.absoluteString))"                
-                switch self.fingerprintCheckingMode {
-                case .strict:
-                    throw StringError(message)
-                case .warn:
-                    observabilityScope.emit(warning: message)
-                case .none:
-                    return
-                }
+            } catch {
+                observabilityScope.emit(warning: "Failed to save revision '\(revision.identifier) from \(sourceControlURL) to fingerprints storage: \(error)")
             }
         } catch {
             self.observabilityScope.emit(error: "Failed to get source control fingerprint for \(self.package) version \(version) from storage: \(error)")
@@ -205,8 +201,6 @@ internal final class SourceControlPackageContainer: PackageContainer, CustomStri
                 throw StringError(message)
             case .warn:
                 observabilityScope.emit(warning: message)
-            case .none:
-                return
             }
         }
     }

Sources/Workspace/Workspace.swift

@@ -217,7 +217,7 @@ public class Workspace {
     fileprivate let checksumAlgorithm: HashAlgorithm
 
     /// The package fingerprint storage
-    fileprivate let fingerprintStorage: PackageFingerprintStorage
+    fileprivate let fingerprintStorage: PackageFingerprintStorage?
 
     /// Enable prefetching containers in resolver.
     fileprivate let resolverPrefetchingEnabled: Bool
@@ -259,6 +259,7 @@ public class Workspace {
     ///   - customHTTPClient: A custom http client.
     ///   - customArchiver: A custom archiver.
     ///   - customChecksumAlgorithm: A custom checksum algorithm.
+    ///   - customFingerprintStorage: A custom fingerprint storage.
     ///   - additionalFileRules: File rules to determine resource handling behavior.
     ///   - resolverUpdateEnabled: Enables the dependencies resolver automatic version update check.  Enabled by default. When disabled the resolver relies only on the resolved version file
     ///   - resolverPrefetchingEnabled: Enables the dependencies resolver prefetching based on the resolved version file.  Enabled by default.
@@ -306,10 +307,12 @@ public class Workspace {
             delegate: delegate.map(WorkspaceRepositoryManagerDelegate.init(workspaceDelegate:)),
             cachePath: sharedRepositoriesCacheEnabled ? location.sharedRepositoriesCacheDirectory : .none
         )        
-        let fingerprintStorage = customFingerprintStorage ?? FilePackageFingerprintStorage(
-            fileSystem: fileSystem,
-            directoryPath: location.sharedFingerprintsDirectory
-        )
+        let fingerprintStorage = customFingerprintStorage ?? location.sharedFingerprintsDirectory.map {
+            FilePackageFingerprintStorage(
+                fileSystem: fileSystem,
+                directoryPath: $0
+            )
+        }
 
         let registryClient = customRegistryClient ?? registries.map { configuration in
             RegistryClient(

Sources/Workspace/WorkspaceConfiguration.swift

@@ -32,7 +32,7 @@ extension Workspace {
         public var resolvedVersionsFile: AbsolutePath
 
         /// Path to the shared security directory
-        public var sharedSecurityDirectory: AbsolutePath
+        public var sharedSecurityDirectory: AbsolutePath?
 
         /// Path to the shared cache directory
         public var sharedCacheDirectory: AbsolutePath?
@@ -61,8 +61,8 @@ extension Workspace {
         }
 
         /// Path to the shared fingerprints directory.
-        public var sharedFingerprintsDirectory: AbsolutePath {
-            self.sharedSecurityDirectory.appending(component: "fingerprints")
+        public var sharedFingerprintsDirectory: AbsolutePath? {
+            self.sharedSecurityDirectory.map { $0.appending(component: "fingerprints") }
         }
 
         /// Path to the shared repositories cache.
@@ -103,7 +103,7 @@ extension Workspace {
             workingDirectory: AbsolutePath,
             editsDirectory: AbsolutePath,
             resolvedVersionsFile: AbsolutePath,
-            sharedSecurityDirectory: AbsolutePath,
+            sharedSecurityDirectory: AbsolutePath?,
             sharedCacheDirectory: AbsolutePath?,
             sharedConfigurationDirectory: AbsolutePath?
         ) {