[codex] structure Electron theme source errors

apps/desktop/src/electron/ElectronTheme.test.ts

@@ -8,6 +8,7 @@ const { onMock, removeListenerMock, themeState } = vi.hoisted(() => ({
   themeState: {
     shouldUseDarkColors: true,
     themeSource: "system",
+    setSourceError: null as unknown,
   },
 }));
 
@@ -17,6 +18,9 @@ vi.mock("electron", () => ({
       return themeState.shouldUseDarkColors;
     },
     set themeSource(value: string) {
+      if (themeState.setSourceError !== null) {
+        throw themeState.setSourceError;
+      }
       themeState.themeSource = value;
     },
     on: onMock,
@@ -32,6 +36,7 @@ describe("ElectronTheme", () => {
     removeListenerMock.mockClear();
     themeState.shouldUseDarkColors = true;
     themeState.themeSource = "system";
+    themeState.setSourceError = null;
   });
 
   it.effect("scopes native theme update listeners", () =>
@@ -49,4 +54,21 @@ describe("ElectronTheme", () => {
       assert.deepEqual(removeListenerMock.mock.calls, [["updated", listener]]);
     }).pipe(Effect.provide(ElectronTheme.layer)),
   );
+
+  it.effect("preserves the requested source and cause when setting the theme fails", () =>
+    Effect.gen(function* () {
+      const cause = new Error("theme source failed");
+      themeState.setSourceError = cause;
+      const electronTheme = yield* ElectronTheme.ElectronTheme;
+
+      const error = yield* Effect.flip(electronTheme.setSource("dark"));
+
+      assert.instanceOf(error, ElectronTheme.ElectronThemeSetSourceError);
+      assert.isTrue(ElectronTheme.isElectronThemeSetSourceError(error));
+      assert.strictEqual(error.source, "dark");
+      assert.strictEqual(error.cause, cause);
+      assert.include(error.message, "dark");
+      assert.notInclude(error.message, cause.message);
+    }).pipe(Effect.provide(ElectronTheme.layer)),
+  );
 });

apps/desktop/src/electron/ElectronTheme.ts

@@ -1,26 +1,43 @@
-import type { DesktopTheme } from "@t3tools/contracts";
+import { DesktopThemeSchema, type DesktopTheme } from "@t3tools/contracts";
 import * as Context from "effect/Context";
 import * as Effect from "effect/Effect";
 import * as Layer from "effect/Layer";
+import * as Schema from "effect/Schema";
 import * as Scope from "effect/Scope";
 
 import * as Electron from "electron";
 
+export class ElectronThemeSetSourceError extends Schema.TaggedErrorClass<ElectronThemeSetSourceError>()(
+  "ElectronThemeSetSourceError",
+  {
+    source: DesktopThemeSchema,
+    cause: Schema.Defect(),
+  },
+) {
+  override get message(): string {
+    return `Failed to set the Electron theme source to ${this.source}.`;
+  }
+}
+
+export const isElectronThemeSetSourceError = Schema.is(ElectronThemeSetSourceError);
+
 export class ElectronTheme extends Context.Service<
   ElectronTheme,
   {
     readonly shouldUseDarkColors: Effect.Effect<boolean>;
-    readonly setSource: (theme: DesktopTheme) => Effect.Effect<void>;
+    readonly setSource: (theme: DesktopTheme) => Effect.Effect<void, ElectronThemeSetSourceError>;
     readonly onUpdated: (listener: () => void) => Effect.Effect<void, never, Scope.Scope>;
   }
 >()("@t3tools/desktop/electron/ElectronTheme") {}
 
 export const make = ElectronTheme.of({
   shouldUseDarkColors: Effect.sync(() => Electron.nativeTheme.shouldUseDarkColors),
   setSource: (theme) =>
-    Effect.suspend(() => {
-      Electron.nativeTheme.themeSource = theme;
-      return Effect.void;
+    Effect.try({
+      try: () => {
+        Electron.nativeTheme.themeSource = theme;
+      },
+      catch: (cause) => new ElectronThemeSetSourceError({ source: theme, cause }),
     }),
   onUpdated: (listener) =>
     Effect.acquireRelease(