Fix build errors on Linux

.github/workflows/ci.yml

@@ -0,0 +1,48 @@
+name: CI
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+
+jobs:
+  unit_tests:
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [macos-latest, macos-15-intel, ubuntu-latest, ubuntu-24.04-arm]
+        traits: ["none", "Foundation"]
+    runs-on: ${{ matrix.os }}
+
+    steps:
+    - uses: actions/checkout@v6
+    - uses: SwiftyLab/setup-swift@latest
+    - name: Determine traits flags
+      id: traits
+      run: |
+        if [[ ${{ matrix.traits }} = 'all' ]]; then
+          echo "flags=--enable-all-traits" >> $GITHUB_OUTPUT
+        elif [[ ${{ matrix.traits }} = 'none' ]]; then
+          echo "flags=--disable-default-traits" >> $GITHUB_OUTPUT
+        else
+          echo "flags=--traits ${{ matrix.traits }}" >> $GITHUB_OUTPUT
+        fi
+    - name: Build
+      run: swift build --build-tests --enable-code-coverage -v ${{ steps.traits.outputs.flags }}
+    - name: Run tests
+      run: swift test --enable-code-coverage -v ${{ steps.traits.outputs.flags }} --xunit-output testresults.xml
+    - name: Collect artifacts
+      if: always()
+      run: |
+        mkdir -p artifacts
+        cp testresults*.xml artifacts/ 2>/dev/null || true
+        find .build -path "*/codecov/*.json" | xargs -I{} cp {} artifacts/ 2>/dev/null || true
+
+    - name: Upload test results
+      uses: actions/upload-artifact@v7
+      if: always()
+      with:
+        name: test-results-${{ matrix.os }}-${{ matrix.traits }}
+        path: artifacts/
+

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version:6.1
+// swift-tools-version:6.2
 
 import PackageDescription
 
@@ -20,11 +20,15 @@ let package = Package(
     traits: [
         "Foundation"
     ],
-    dependencies: [],
+    dependencies: [
+        .package(url: "https://github.com/apple/swift-system", from: "1.6.1"),
+    ],
     targets: [
         .target(
             name: "CSErrors",
-            dependencies: []
+            dependencies: [
+                .product(name: "SystemPackage", package: "swift-system", condition: .when(platforms: [.linux]))
+            ]
         ),
         .testTarget(
             name: "CSErrorsTests",

Sources/CSErrors/CocoaError+CSErrors.swift

@@ -5,7 +5,12 @@
 //  Created by Charles Srstka on 4/17/20.
 //
 
-import System
+
+#if canImport(Darwin)
+import Darwin
+#elseif canImport(Glibc)
+import Glibc
+#endif
 
 #if Foundation
 #if canImport(FoundationEssentials)
@@ -14,6 +19,12 @@ import FoundationEssentials
 import Foundation
 #endif
 
+#if canImport(SystemPackage)
+import SystemPackage
+#else
+import System
+#endif
+
 internal func cocoaCode(posixCode: Int32, isWrite: Bool) -> CocoaError.Code? {
     switch posixCode {
     case EPERM, EACCES:
@@ -28,8 +39,10 @@ internal func cocoaCode(posixCode: Int32, isWrite: Bool) -> CocoaError.Code? {
         return .fileWriteOutOfSpace
     case EROFS:
         return .fileWriteVolumeReadOnly
+#if canImport(Darwin)
     case EFTYPE:
         return .fileReadCorruptFile
+#endif
     case ECANCELED:
         return .userCancelled
     default:
@@ -94,7 +107,15 @@ extension CocoaError {
         var userInfo = metadata.toUserInfo()
 
         if let stringEncoding {
-            userInfo[NSStringEncodingErrorKey] = stringEncoding.rawValue
+            // The Darwin version of Foundation stores this as a UInt, other platforms store it as an NSNumber
+            // Also, the string keys they use are different.
+            // https://github.com/swiftlang/swift-foundation/blob/b011018acca72a38179bd4ac9d0377d2f90b4cff/Sources/FoundationEssentials/Error/CocoaError.swift#L108-L114
+
+#if Foundation && canImport(Darwin)
+            userInfo[NSStringEncodingErrorKey] = NSNumber(value: stringEncoding.rawValue)
+#endif
+
+            userInfo[NSStringEncodingErrorKeyNonDarwin] = Int(stringEncoding.rawValue)
         }
 
         self.init(code, userInfo: userInfo)
@@ -159,11 +180,20 @@ extension CocoaError {
 
 extension CocoaError: CSErrorProtocol {
     public var isFileNotFoundError: Bool {
-        [.fileNoSuchFile, .fileReadNoSuchFile, .ubiquitousFileUnavailable].contains(self.code)
+        switch self.code {
+        case .fileNoSuchFile, .fileReadNoSuchFile: true
+#if canImport(Darwin)
+        case .ubiquitousFileUnavailable: true
+#endif
+        default: false
+        }
     }
 
     public var isPermissionError: Bool {
-        [.fileReadNoPermission, .fileWriteNoPermission].contains(self.code)
+        switch self.code {
+        case .fileReadNoPermission, .fileWriteNoPermission: true
+        default: false
+        }
     }
 
     public var isCancelledError: Bool {

Sources/CSErrors/Error+CSErrors.swift

@@ -5,7 +5,11 @@
 //  Created by Charles Srstka on 12/27/15.
 //
 
+#if canImport(SystemPackage)
+import SystemPackage
+#else
 import System
+#endif
 
 #if canImport(Darwin)
 import Darwin
@@ -25,25 +29,23 @@ extension Error {
     /// True if the error represents a “File Not Found” error, regardless of domain.
     public var isFileNotFoundError: Bool {
         if #available(macOS 11.0, iOS 14.0, tvOS 14.0, watchOS 7.0, macCatalyst 14.0, *), versionCheck(11),
-           let errno = self as? System.Errno, errno == .noSuchFileOrDirectory {
+           let errno = self as? Errno, errno == .noSuchFileOrDirectory {
             return true
         }
 
         if let err = self.toErrno(), err == ENOENT {
             return true
         }
 
-#if canImport(Darwin)
         if let osStatus = self.toOSStatus(), OSStatusError.Codes.fileNotFoundErrors.contains(osStatus) {
             return true
         }
-#endif
 
         if let err = self as? any CSErrorProtocol, err.isFileNotFoundError {
             return true
         }
 
-#if Foundation
+#if Foundation && canImport(Darwin)
         if let err = (self as NSError).toCSErrorProtocol(), err.isFileNotFoundError {
             return true
         }
@@ -55,7 +57,7 @@ extension Error {
     /// True if the error represents a permission or access error, regardless of domain.
     public var isPermissionError: Bool {
         if #available(macOS 11.0, iOS 14.0, tvOS 14.0, watchOS 7.0, macCatalyst 14.0, *), versionCheck(11),
-            let errno = self as? System.Errno, [.permissionDenied, .notPermitted].contains(errno)
+            let errno = self as? Errno, [.permissionDenied, .notPermitted].contains(errno)
         {
             return true
         }
@@ -64,17 +66,15 @@ extension Error {
             return true
         }
 
-#if canImport(Darwin)
         if let osStatus = self.toOSStatus(), OSStatusError.Codes.permissionErrors.contains(osStatus) {
             return true
         }
-#endif
 
         if let err = self as? any CSErrorProtocol, err.isPermissionError {
             return true
         }
 
-#if Foundation
+#if Foundation && canImport(Darwin)
         if let err = (self as NSError).toCSErrorProtocol(), err.isPermissionError {
             return true
         }
@@ -86,7 +86,7 @@ extension Error {
     /// True if the error results from a user cancellation, regardless of domain.
     public var isCancelledError: Bool {
         if #available(macOS 11.0, iOS 14.0, tvOS 14.0, watchOS 7.0, macCatalyst 14.0, *), versionCheck(11),
-            let errno = self as? System.Errno, errno == .canceled
+            let errno = self as? Errno, errno == .canceled
         {
             return true
         }
@@ -95,17 +95,15 @@ extension Error {
             return true
         }
 
-#if canImport(Darwin)
         if let err = self.toOSStatus(), OSStatusError.Codes.cancelErrors.contains(err) {
             return true
         }
-#endif
 
         if let err = self as? any CSErrorProtocol, err.isCancelledError {
             return true
         }
 
-#if Foundation
+#if Foundation && canImport(Darwin)
         if let err = (self as NSError).toCSErrorProtocol(), err.isCancelledError {
             return true
         }

Sources/CSErrors/ErrorMetadata.swift

@@ -5,16 +5,32 @@
 //  Created by Charles Srstka on 1/11/23.
 //
 
+#if canImport(SystemPackage)
+import SystemPackage
+#else
 import System
+#endif
 
 #if Foundation
 #if canImport(FoundationEssentials)
 import FoundationEssentials
+let NSFilePathErrorKey = "NSFilePath"
+let NSHelpAnchorErrorKey = "NSHelpAnchor"
+let NSLocalizedDescriptionKey = "NSLocalizedDescription"
+let NSLocalizedFailureReasonErrorKey = "NSLocalizedFailureReason"
+let NSRecoveryAttempterErrorKey = "NSRecoveryAttempter"
+let NSLocalizedRecoveryOptionsErrorKey = "NSLocalizedRecoveryOptions"
+let NSLocalizedRecoverySuggestionErrorKey = "NSLocalizedRecoverySuggestion"
+let NSStringEncodingErrorKey = "NSStringEncoding"
+let NSUnderlyingErrorKey = "NSUnderlyingError"
+let NSURLErrorKey = "NSURL"
 #else
 import Foundation
 #endif
 #endif
 
+let NSStringEncodingErrorKeyNonDarwin = "NSStringEncodingErrorKey"
+
 public struct ErrorMetadata: Sendable {
     public let description: String?
     public internal(set) var failureReason: String?
@@ -159,7 +175,15 @@ public struct ErrorMetadata: Sendable {
         }
 
         if let stringEncoding {
-            custom[NSStringEncodingErrorKey] = stringEncoding.rawValue
+            // The Darwin version of Foundation stores this as a UInt, other platforms store it as an NSNumber
+            // Also, the string keys they use are different.
+            // https://github.com/swiftlang/swift-foundation/blob/b011018acca72a38179bd4ac9d0377d2f90b4cff/Sources/FoundationEssentials/Error/CocoaError.swift#L108-L114
+
+#if Foundation && canImport(Darwin)
+            custom[NSStringEncodingErrorKey] = NSNumber(value: stringEncoding.rawValue)
+#endif
+
+            custom[NSStringEncodingErrorKeyNonDarwin] = Int(stringEncoding.rawValue)
         }
 
         self.init(
@@ -233,20 +257,30 @@ public struct ErrorMetadata: Sendable {
             return url
         }
 
+#if canImport(Darwin)
         if #available(macOS 13.0, iOS 16.0, tvOS 16.0, watchOS 9.0, macCatalyst 16.1, *), versionCheck(13),
            let path = self.path, let url = URL(filePath: path) {
             return url
         } else if let path = self.pathString {
             return URL(fileURLWithPath: path)
         }
+#else
+        if let path = self.path {
+            return URL(filePath: path.string)
+        }
+#endif
 
         return nil
     }
 
     public var stringEncoding: String.Encoding? {
-        guard let rawEncoding = self.custom?[NSStringEncodingErrorKey] as? UInt else { return nil }
+        if let rawEncoding = self.custom?[NSStringEncodingErrorKey] as? UInt {
+            return String.Encoding(rawValue: rawEncoding)
+        } else if let rawEncoding = self.custom?[NSStringEncodingErrorKeyNonDarwin] as? Int {
+            return String.Encoding(rawValue: UInt(rawEncoding))
+        }
 
-        return String.Encoding(rawValue: rawEncoding)
+        return nil
     }
 #endif
 }

Sources/CSErrors/HTTPError.swift

@@ -16,7 +16,7 @@ public struct HTTPError: CSErrorProtocol {
     public var failureReason: String? {
         var reason = "HTTP \(self.statusCode)"
 
-#if Foundation
+#if Foundation && canImport(Darwin)
         reason += " (\(HTTPURLResponse.localizedString(forStatusCode: self.statusCode)))"
 #endif
 

Sources/CSErrors/NSError+CSErrors.swift

@@ -5,15 +5,16 @@
 //  Created by Charles Srstka on 11/11/23.
 //
 
-import System
+#if Foundation && canImport(Darwin)
 
-#if Foundation
 #if canImport(FoundationEssentials)
 import FoundationEssentials
 #else
 import Foundation
 #endif
 
+import System
+
 extension NSError {
     internal func toCSErrorProtocol() -> (any CSErrorProtocol)? {
         switch self.domain {