Extract CmuxFoundation package (modular refactor, wave 1)

Packages/CmuxFoundation/Package.swift

@@ -0,0 +1,30 @@
+// swift-tools-version: 6.0
+
+import PackageDescription
+
+let package = Package(
+    name: "CmuxFoundation",
+    platforms: [
+        .macOS(.v14),
+    ],
+    products: [
+        .library(
+            name: "CmuxFoundation",
+            targets: ["CmuxFoundation"]
+        ),
+    ],
+    targets: [
+        .target(
+            name: "CmuxFoundation",
+            swiftSettings: [
+                .swiftLanguageMode(.v6),
+                .enableUpcomingFeature("ExistentialAny"),
+                .enableUpcomingFeature("InternalImportsByDefault"),
+            ]
+        ),
+        .testTarget(
+            name: "CmuxFoundationTests",
+            dependencies: ["CmuxFoundation"]
+        ),
+    ]
+)

Packages/CmuxFoundation/README.md

@@ -0,0 +1,38 @@
+# CmuxFoundation
+
+Shared low-level primitives for cmux with no internal package dependencies. This is the
+bottom of the package dependency graph: encoding/text helpers, value types, and other
+cross-cutting utilities that several domains need, with nothing in here depending on AppKit,
+SwiftUI, or another cmux package.
+
+It exists as the leaf every other package and the app target can depend on without creating
+a cycle. Keep it dependency-free.
+
+Foundation helpers are exposed as extensions on existing types rather than free functions,
+so call sites read naturally (`value.javaScriptStringLiteral`, not `f(value)`).
+
+## Contents
+
+- `String.javaScriptStringLiteral` — the string encoded as a quoted JavaScript string literal.
+
+## Usage
+
+```swift
+import CmuxFoundation
+
+let literal = userText?.javaScriptStringLiteral ?? "null"
+webView.evaluateJavaScript("setValue(\(literal))")
+```
+
+## Testing
+
+Everything here is a pure value transform, so tests need no app, no AppKit, and no filesystem:
+
+```swift
+import Testing
+import CmuxFoundation
+
+@Test func plainStringIsQuoted() {
+    #expect("hello".javaScriptStringLiteral == "\"hello\"")
+}
+```

Packages/CmuxFoundation/Sources/CmuxFoundation/String+JavaScriptStringLiteral.swift

@@ -0,0 +1,26 @@
+import Foundation
+
+public extension String {
+    /// This string encoded as a quoted JavaScript string literal, ready to splice into JS source.
+    ///
+    /// The value includes the surrounding double quotes and escapes any characters (quotes,
+    /// backslashes, control characters) that would otherwise break out of the literal. Encoding
+    /// goes through `JSONSerialization`, so the result is also a valid JSON string.
+    ///
+    /// ```swift
+    /// "a\"b".javaScriptStringLiteral                       // -> "\"a\\\"b\""
+    /// webView.evaluateJavaScript("setValue(\(id?.javaScriptStringLiteral ?? "null"))")
+    /// ```
+    ///
+    /// - Returns: The quoted JS string literal, or `nil` if the string cannot be encoded.
+    var javaScriptStringLiteral: String? {
+        // [self] is always valid JSON; reuse JSON's escaping and drop the array brackets to
+        // get a quoted JS string literal.
+        guard let data = try? JSONSerialization.data(withJSONObject: [self]),
+              let arrayLiteral = String(data: data, encoding: .utf8),
+              arrayLiteral.count >= 2 else {
+            return nil
+        }
+        return String(arrayLiteral.dropFirst().dropLast())
+    }
+}

Packages/CmuxFoundation/Tests/CmuxFoundationTests/String+JavaScriptStringLiteralTests.swift

@@ -0,0 +1,25 @@
+import Testing
+
+import CmuxFoundation
+
+@Suite struct StringJavaScriptStringLiteralTests {
+    @Test func plainStringIsQuoted() {
+        #expect("hello".javaScriptStringLiteral == "\"hello\"")
+    }
+
+    @Test func emptyStringIsEmptyQuotes() {
+        #expect("".javaScriptStringLiteral == "\"\"")
+    }
+
+    @Test func escapesDoubleQuotesAndBackslashes() {
+        #expect(#"a"b\c"#.javaScriptStringLiteral == #""a\"b\\c""#)
+    }
+
+    @Test func escapesNewlines() {
+        #expect("line1\nline2".javaScriptStringLiteral == #""line1\nline2""#)
+    }
+
+    @Test func preservesUnicode() {
+        #expect("café".javaScriptStringLiteral == "\"café\"")
+    }
+}

Sources/AppDelegate.swift

@@ -9,17 +9,7 @@ import WebKit
 import Combine
 import ObjectiveC.runtime
 import Darwin
-
-func cmuxJavaScriptStringLiteral(_ value: String?) -> String? {
-    guard let value else { return nil }
-    // Serialize as a JSON array, then strip the outer brackets to get a quoted JS string literal.
-    guard let data = try? JSONSerialization.data(withJSONObject: [value]),
-          let arrayLiteral = String(data: data, encoding: .utf8),
-          arrayLiteral.count >= 2 else {
-        return nil
-    }
-    return String(arrayLiteral.dropFirst().dropLast())
-}
+import CmuxFoundation
 
 private struct MultiWindowRouteCLIResult {
     let status: String
@@ -10524,7 +10514,7 @@ final class AppDelegate: NSObject, NSApplicationDelegate, UNUserNotificationCent
         awaitingInputId: String? = nil,
         completion: @escaping ([String: String]) -> Void
     ) {
-        let expectedInputIdLiteral = cmuxJavaScriptStringLiteral(awaitingInputId) ?? "null"
+        let expectedInputIdLiteral = awaitingInputId?.javaScriptStringLiteral ?? "null"
         let script = """
         (() => {
           const expectedInputId = \(expectedInputIdLiteral);

cmux.xcodeproj/project.pbxproj

@@ -140,6 +140,7 @@
 		E7E000000000000000000001 /* CmuxEventStream.swift in Sources */ = {isa = PBXBuildFile; fileRef = E7E000000000000000000002 /* CmuxEventStream.swift */; };
 		C0DE46000000000000000001 /* CMUXExtensionClient in Frameworks */ = {isa = PBXBuildFile; productRef = C0DE46000000000000000002 /* CMUXExtensionClient */; };
 		C0DE45000000000000000001 /* CmuxExtensionKit in Frameworks */ = {isa = PBXBuildFile; productRef = C0DE45000000000000000002 /* CmuxExtensionKit */; };
+		CF00F00000000000000000A3 /* CmuxFoundation in Frameworks */ = {isa = PBXBuildFile; productRef = CF00F00000000000000000A2 /* CmuxFoundation */; };
 		C0DE34020000000000000001 /* CmuxHelpCommands.swift in Sources */ = {isa = PBXBuildFile; fileRef = C0DE34020000000000000003 /* CmuxHelpCommands.swift */; };
 		C0DE34020000000000000002 /* CmuxHelpResource.swift in Sources */ = {isa = PBXBuildFile; fileRef = C0DE34020000000000000004 /* CmuxHelpResource.swift */; };
 		C0DE46010000000000000001 /* CMUXInstalledExtensionSidebarHostView.swift in Sources */ = {isa = PBXBuildFile; fileRef = C0DE46010000000000000002 /* CMUXInstalledExtensionSidebarHostView.swift */; };
@@ -1216,6 +1217,7 @@
 				5EDB6027B346C46521A93C74 /* CMUXAuthCore in Frameworks */,
 				C0DE46000000000000000001 /* CMUXExtensionClient in Frameworks */,
 				C0DE45000000000000000001 /* CmuxExtensionKit in Frameworks */,
+				CF00F00000000000000000A3 /* CmuxFoundation in Frameworks */,
 				3069F1D10000000000000005 /* CMUXPasteboardFidelity in Frameworks */,
 				A5C0DE0000000000000000A3 /* CMUXProjectModel in Frameworks */,
 				CD0CFE5300000000CD0CFE53 /* CmuxSettings in Frameworks */,
@@ -1935,6 +1937,7 @@
 				A500D013A1B2C3D4E5F60718 /* CMUXDebugLog */,
 				CD0CFE5200000000CD0CFE52 /* CmuxSettings */,
 				CD0CFE5500000000CD0CFE55 /* CmuxSettingsUI */,
+				CF00F00000000000000000A2 /* CmuxFoundation */,
 				A8BD195031FC4B82B4354297 /* StackAuth */,
 			);
 			productName = cmux;
@@ -2072,6 +2075,7 @@
 				A5354304A5354304A5354304 /* XCLocalSwiftPackageReference "CMUXSocketPathDomain" */,
 				CD0CFE5100000000CD0CFE51 /* XCLocalSwiftPackageReference "CmuxSettings" */,
 				CD0CFE5400000000CD0CFE54 /* XCLocalSwiftPackageReference "CmuxSettingsUI" */,
+				CF00F00000000000000000A1 /* XCLocalSwiftPackageReference "CmuxFoundation" */,
 				28B798BB9086C8E6B60C3355 /* XCLocalSwiftPackageReference "stack-auth-swift-sdk-prerelease" */,
 			);
 			productRefGroup = A5001042 /* Products */;
@@ -3198,6 +3202,10 @@
 			isa = XCLocalSwiftPackageReference;
 			relativePath = Packages/CmuxSettingsUI;
 		};
+		CF00F00000000000000000A1 /* XCLocalSwiftPackageReference "CmuxFoundation" */ = {
+			isa = XCLocalSwiftPackageReference;
+			relativePath = Packages/CmuxFoundation;
+		};
 		A5001260 /* XCLocalSwiftPackageReference "bonsplit" */ = {
 			isa = XCLocalSwiftPackageReference;
 			relativePath = vendor/bonsplit;
@@ -3300,6 +3308,11 @@
 			package = CD0CFE5400000000CD0CFE54 /* XCLocalSwiftPackageReference "CmuxSettingsUI" */;
 			productName = CmuxSettingsUI;
 		};
+		CF00F00000000000000000A2 /* CmuxFoundation */ = {
+			isa = XCSwiftPackageProductDependency;
+			package = CF00F00000000000000000A1 /* XCLocalSwiftPackageReference "CmuxFoundation" */;
+			productName = CmuxFoundation;
+		};
 		A5001231 /* Sparkle */ = {
 			isa = XCSwiftPackageProductDependency;
 			package = A5001232 /* XCRemoteSwiftPackageReference "Sparkle" */;