Cache Ghostty config loads on UI path

Fixes CMUXTERM-MACOS-A7

Sources/GhosttyConfig.swift

@@ -2,11 +2,14 @@ import Foundation
 import AppKit
 
 struct GhosttyConfig {
-    enum ColorSchemePreference {
+    enum ColorSchemePreference: Hashable {
         case light
         case dark
     }
 
+    private static let loadCacheLock = NSLock()
+    private static var cachedConfigsByColorScheme: [ColorSchemePreference: GhosttyConfig] = [:]
+
     var fontFamily: String = "Menlo"
     var fontSize: CGFloat = 12
     var theme: String?
@@ -45,7 +48,45 @@ struct GhosttyConfig {
         return backgroundColor.darken(by: isLightBackground ? 0.08 : 0.4)
     }
 
-    static func load() -> GhosttyConfig {
+    static func load(
+        preferredColorScheme: ColorSchemePreference? = nil,
+        useCache: Bool = true,
+        loadFromDisk: (_ preferredColorScheme: ColorSchemePreference) -> GhosttyConfig = Self.loadFromDisk
+    ) -> GhosttyConfig {
+        let resolvedColorScheme = preferredColorScheme ?? currentColorSchemePreference()
+        if useCache, let cached = cachedLoad(for: resolvedColorScheme) {
+            return cached
+        }
+
+        let loaded = loadFromDisk(resolvedColorScheme)
+        if useCache {
+            storeCachedLoad(loaded, for: resolvedColorScheme)
+        }
+        return loaded
+    }
+
+    static func invalidateLoadCache() {
+        loadCacheLock.lock()
+        cachedConfigsByColorScheme.removeAll()
+        loadCacheLock.unlock()
+    }
+
+    private static func cachedLoad(for colorScheme: ColorSchemePreference) -> GhosttyConfig? {
+        loadCacheLock.lock()
+        defer { loadCacheLock.unlock() }
+        return cachedConfigsByColorScheme[colorScheme]
+    }
+
+    private static func storeCachedLoad(
+        _ config: GhosttyConfig,
+        for colorScheme: ColorSchemePreference
+    ) {
+        loadCacheLock.lock()
+        cachedConfigsByColorScheme[colorScheme] = config
+        loadCacheLock.unlock()
+    }
+
+    private static func loadFromDisk(preferredColorScheme: ColorSchemePreference) -> GhosttyConfig {
         var config = GhosttyConfig()
 
         // Match Ghostty's default load order on macOS.
@@ -64,7 +105,12 @@ struct GhosttyConfig {
 
         // Load theme if specified
         if let themeName = config.theme {
-            config.loadTheme(themeName)
+            config.loadTheme(
+                themeName,
+                environment: ProcessInfo.processInfo.environment,
+                bundleResourceURL: Bundle.main.resourceURL,
+                preferredColorScheme: preferredColorScheme
+            )
         }
 
         return config

Sources/WorkspaceContentView.swift

@@ -117,6 +117,7 @@ struct WorkspaceContentView: View {
             syncBonsplitNotificationBadges()
         }
         .onReceive(NotificationCenter.default.publisher(for: .ghosttyConfigDidReload)) { _ in
+            GhosttyConfig.invalidateLoadCache()
             refreshGhosttyAppearanceConfig(reason: "ghosttyConfigDidReload")
         }
         .onChange(of: colorScheme) { oldValue, newValue in
@@ -175,7 +176,7 @@ struct WorkspaceContentView: View {
     static func resolveGhosttyAppearanceConfig(
         reason: String = "unspecified",
         backgroundOverride: NSColor? = nil,
-        loadConfig: () -> GhosttyConfig = GhosttyConfig.load,
+        loadConfig: () -> GhosttyConfig = { GhosttyConfig.load() },
         defaultBackground: () -> NSColor = { GhosttyApp.shared.defaultBackgroundColor }
     ) -> GhosttyConfig {
         var next = loadConfig()

cmuxTests/GhosttyConfigTests.swift

@@ -126,6 +126,64 @@ final class GhosttyConfigTests: XCTestCase {
         XCTAssertEqual(rgb255(config.backgroundColor), RGB(red: 253, green: 246, blue: 227))
     }
 
+    func testLoadCachesPerColorScheme() {
+        GhosttyConfig.invalidateLoadCache()
+        defer { GhosttyConfig.invalidateLoadCache() }
+
+        var loadCount = 0
+        let loadFromDisk: (GhosttyConfig.ColorSchemePreference) -> GhosttyConfig = { scheme in
+            loadCount += 1
+            var config = GhosttyConfig()
+            config.fontFamily = "\(scheme)-\(loadCount)"
+            return config
+        }
+
+        let lightFirst = GhosttyConfig.load(
+            preferredColorScheme: .light,
+            loadFromDisk: loadFromDisk
+        )
+        let lightSecond = GhosttyConfig.load(
+            preferredColorScheme: .light,
+            loadFromDisk: loadFromDisk
+        )
+        let darkFirst = GhosttyConfig.load(
+            preferredColorScheme: .dark,
+            loadFromDisk: loadFromDisk
+        )
+
+        XCTAssertEqual(loadCount, 2)
+        XCTAssertEqual(lightFirst.fontFamily, "light-1")
+        XCTAssertEqual(lightSecond.fontFamily, "light-1")
+        XCTAssertEqual(darkFirst.fontFamily, "dark-2")
+    }
+
+    func testLoadCacheInvalidationForcesReload() {
+        GhosttyConfig.invalidateLoadCache()
+        defer { GhosttyConfig.invalidateLoadCache() }
+
+        var loadCount = 0
+        let loadFromDisk: (GhosttyConfig.ColorSchemePreference) -> GhosttyConfig = { _ in
+            loadCount += 1
+            var config = GhosttyConfig()
+            config.fontFamily = "reload-\(loadCount)"
+            return config
+        }
+
+        let first = GhosttyConfig.load(
+            preferredColorScheme: .dark,
+            loadFromDisk: loadFromDisk
+        )
+        GhosttyConfig.invalidateLoadCache()
+        let second = GhosttyConfig.load(
+            preferredColorScheme: .dark,
+            loadFromDisk: loadFromDisk
+        )
+
+        XCTAssertEqual(loadCount, 2)
+        XCTAssertEqual(first.fontFamily, "reload-1")
+        XCTAssertEqual(second.fontFamily, "reload-2")
+    }
+
     func testLegacyConfigFallbackUsesLegacyFileWhenConfigGhosttyIsEmpty() {
         XCTAssertTrue(
             GhosttyApp.shouldLoadLegacyGhosttyConfig(