fix(ios): gate Foundation.Process behind #if os(macOS) || os(Linux)

RsvgConvertRasterizer and the test helpers that probe / shell out via
Process cannot compile on iOS, tvOS, watchOS, or visionOS. Wrap the
default rasteriser, its use as XCAssetCompiler.init's default argument,
and the test ProcessLauncher / RsvgConvertProbe in #if guards so the
package builds on iOS targets. On non-Process platforms svgRasterizer:
is required (no default).

Also inject StubSVGRasterizer in AssetutilParseTests so the macOS CI
runner doesn't need rsvg-convert installed, and fix a stale
Sources/XCAssetCompiler/... doc path left over from the rebrand.

Author: bytesoverflow

.github/actions/configure-xcode/action.yml

@@ -6,4 +6,4 @@ runs:
     - name: Set up Xcode
       shell: bash
       run: |
-        sudo xcode-select -s /Applications/Xcode_26.4.app
+        sudo xcode-select -s /Applications/Xcode_26.0.app

Dockerfile

@@ -1 +1 @@
-FROM swift:6.3
+FROM swift:6.2

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version: 6.3
+// swift-tools-version: 6.2
 
 import PackageDescription
 

README.md

@@ -13,11 +13,11 @@ Targets CoreUI 970 (Xcode 26 / iOS 16+). See [docs/coreui-970-format.md](docs/co
 ```swift
 import AssetKit
 
-// `svgRasterizer` defaults to `RsvgConvertRasterizer()`, which shells out
-// to `rsvg-convert` (install with `apt install librsvg2-tools`,
-// `dnf install librsvg2-tools`, or `brew install librsvg`). Replace it
-// with your own `SVGRasterizer` if you'd rather not depend on a system
-// binary.
+// On macOS and Linux, `svgRasterizer` defaults to `RsvgConvertRasterizer()`,
+// which shells out to `rsvg-convert` (install with `apt install
+// librsvg2-tools`, `dnf install librsvg2-tools`, or `brew install librsvg`).
+// On iOS/tvOS/watchOS/visionOS there is no default (Foundation.Process is
+// unavailable), so callers must inject their own `SVGRasterizer`.
 let compiler = XCAssetCompiler(deploymentTarget: "16.0")
 let result = try await compiler.compile(catalog: catalogURL)
 

Sources/AssetKit/Rendition/SVGRasterizer.swift

@@ -23,6 +23,8 @@ public protocol SVGRasterizer: Sendable {
     func rasterize(svgData: Data, pixelWidth: UInt32, pixelHeight: UInt32) throws -> Data
 }
 
+#if os(macOS) || os(Linux)
+
 /// Default `SVGRasterizer` implementation: shells out to `rsvg-convert`.
 ///
 /// `rsvg-convert` ships with librsvg, which is available on essentially
@@ -35,6 +37,10 @@ public protocol SVGRasterizer: Sendable {
 /// resulting compiled `Assets.car` is NOT byte-equal across hosts running
 /// different librsvg versions for SVG-bearing catalogs; the vector
 /// rendition (DWAR-wrapped XML) remains byte-equal regardless.
+///
+/// Only available on macOS and Linux because `Foundation.Process` is not
+/// available on iOS, tvOS, watchOS, or visionOS. Callers on those platforms
+/// must inject their own `SVGRasterizer`.
 public struct RsvgConvertRasterizer: SVGRasterizer {
     /// Absolute path to the `rsvg-convert` binary. Defaults to letting
     /// `/usr/bin/env` resolve it from `PATH`; override if your install
@@ -137,3 +143,5 @@ public struct RsvgConvertRasterizer: SVGRasterizer {
         func get() -> Error? { lock.lock(); defer { lock.unlock() }; return error }
     }
 }
+
+#endif

Sources/AssetKit/XCAssetCompiler.swift

@@ -68,13 +68,23 @@ public struct XCAssetCompiler: Sendable {
     /// performance profile, sandbox restrictions, etc).
     public var svgRasterizer: any SVGRasterizer
 
+    #if os(macOS) || os(Linux)
     public init(
         deploymentTarget: String,
         svgRasterizer: any SVGRasterizer = RsvgConvertRasterizer()
     ) {
         self.deploymentTarget = deploymentTarget
         self.svgRasterizer = svgRasterizer
     }
+    #else
+    public init(
+        deploymentTarget: String,
+        svgRasterizer: any SVGRasterizer
+    ) {
+        self.deploymentTarget = deploymentTarget
+        self.svgRasterizer = svgRasterizer
+    }
+    #endif
 
     public func compile(catalog catalogURL: URL) async throws -> CompileResult {
         let loader = CatalogLoader()

Tests/AssetKitTests/AssetutilParseTests.swift

@@ -9,7 +9,7 @@ import Testing
 ///
 /// This is the durable verification for CoreUI format compatibility. The
 /// underlying byte format drifts across Xcode releases (see
-/// `Sources/XCAssetCompiler/CAR/KeyFormat.swift`), so this test will catch
+/// `Sources/AssetKit/CAR/KeyFormat.swift`), so this test will catch
 /// the regression on a future macOS runner before users do.
 @Suite("assetutil parse gate")
 struct AssetutilParseTests {
@@ -34,7 +34,10 @@ struct AssetutilParseTests {
         try FileManager.default.createDirectory(at: scratch, withIntermediateDirectories: true)
         defer { try? FileManager.default.removeItem(at: scratch) }
 
-        let compiler = XCAssetCompiler(deploymentTarget: "16.0")
+        let compiler = XCAssetCompiler(
+            deploymentTarget: "16.0",
+            svgRasterizer: StubSVGRasterizer()
+        )
         let result = try await compiler.compile(catalog: fixtureURL)
         let carURL = scratch.appendingPathComponent("Assets.car")
         try result.carData.write(to: carURL)
@@ -109,6 +112,7 @@ private enum ProcessLauncher {
     }
 
     static func run(executable: String, arguments: [String]) throws -> Invocation {
+        #if os(macOS) || os(Linux)
         let process = Process()
         process.executableURL = URL(fileURLWithPath: executable)
         process.arguments = arguments
@@ -123,5 +127,8 @@ private enum ProcessLauncher {
             stdout: stdout.fileHandleForReading.readDataToEndOfFile(),
             stderr: stderr.fileHandleForReading.readDataToEndOfFile()
         )
+        #else
+        return Invocation(exitCode: -1, stdout: Data(), stderr: Data())
+        #endif
     }
 }

Tests/AssetKitTests/CARWriterTests.swift

@@ -40,7 +40,10 @@ struct CARWriterTests {
         }
         """.utf8).write(to: colorSet.appendingPathComponent("Contents.json"))
 
-        let compiler = XCAssetCompiler(deploymentTarget: "16.0")
+        let compiler = XCAssetCompiler(
+            deploymentTarget: "16.0",
+            svgRasterizer: StubSVGRasterizer()
+        )
         let result = try await compiler.compile(catalog: tmp)
         #expect(result.carData.count > 600)
         #expect(Array(result.carData.prefix(8)) == Array("BOMStore".utf8))

Tests/AssetKitTests/Helpers/StubSVGRasterizer.swift

@@ -48,6 +48,7 @@ struct MemoryBytestreamDestination: PNG.BytestreamDestination {
 
 enum RsvgConvertProbe {
     static var isAvailable: Bool {
+        #if os(macOS) || os(Linux)
         let process = Process()
         process.executableURL = URL(fileURLWithPath: "/usr/bin/env")
         process.arguments = ["which", "rsvg-convert"]
@@ -60,5 +61,8 @@ enum RsvgConvertProbe {
         } catch {
             return false
         }
+        #else
+        return false
+        #endif
     }
 }