fix(settings): report apply failures without stalling

apps/desktop/src/components/editor/EditorSettingsDialog.vue

@@ -984,13 +984,34 @@ async function persistSettings() {
   }
 }
 
+function applySettingsErrorToast(error: unknown) {
+  toast(t("settings.applyFailed", { error: error instanceof Error ? error.message : String(error) }), 5000);
+}
+
+// Shared apply entrypoint used by both "Apply" and "Apply & Close". Persists the
+// current draft and reports failure explicitly instead of silently swallowing it
+// (persistSettings() has several awaited persistence steps with no try/catch, so a
+// rejected save used to leave "Apply" silent and made "Apply & Close" unclosable with
+// no feedback). Returns whether persistence succeeded so the close path only proceeds
+// once the settings are actually saved.
+async function applySettingsForResult(): Promise<boolean> {
+  try {
+    await persistSettings();
+    return true;
+  } catch (error) {
+    applySettingsErrorToast(error);
+    return false;
+  }
+}
+
 async function applySettings() {
-  await persistSettings();
+  await applySettingsForResult();
 }
 
 async function applySettingsAndClose() {
-  await persistSettings();
-  closeSettings();
+  if (await applySettingsForResult()) {
+    closeSettings();
+  }
 }
 
 async function restartDbxForDuckDbIsolation() {

apps/desktop/src/components/editor/__tests__/EditorSettingsDialog.applyError.spec.ts

@@ -0,0 +1,42 @@
+import { readFileSync } from "node:fs";
+import { describe, expect, it } from "vitest";
+
+const dialogSource = readFileSync(new URL("../EditorSettingsDialog.vue", import.meta.url), "utf8");
+
+// Regression for https://github.com/t8y2/dbx/issues/6485: applying editor
+// settings (e.g. the editor font) could appear to "do nothing" because
+// persistSettings() has several awaited persistence steps with no error
+// handling. On a rejected save, "Apply" was completely silent and "Apply &
+// Close" never called closeSettings(), leaving the dialog stuck open with no
+// feedback at all.
+describe("EditorSettingsDialog apply persistence error handling", () => {
+  it("shares a single apply entrypoint between Apply and Apply & Close", () => {
+    // Both buttons must go through one shared persist/apply routine instead of
+    // each calling persistSettings() directly with divergent semantics.
+    const block = dialogSource.slice(dialogSource.indexOf("function applySettingsErrorToast"), dialogSource.indexOf("async function restartDbxForDuckDbIsolation()"));
+    const entrypointCalls = (block.match(/await applySettingsForResult\(\)/g) || []).length;
+    // one call in applySettings() + one (guarded) call in applySettingsAndClose()
+    expect(entrypointCalls).toBeGreaterThanOrEqual(2);
+    // the shared entrypoint exists and wraps persistSettings
+    expect(block).toContain("async function applySettingsForResult(): Promise<boolean>");
+    expect(block).toContain("await persistSettings();");
+  });
+
+  it("never closes the dialog before persistence succeeds", () => {
+    // "Apply & Close" must only proceed to closeSettings() after a successful
+    // apply. Before the fix, closeSettings() ran unconditionally after
+    // `await persistSettings()`, so a rejected save left the dialog stuck open.
+    const block = dialogSource.slice(dialogSource.indexOf("async function applySettingsAndClose()"), dialogSource.indexOf("async function restartDbxForDuckDbIsolation()"));
+    expect(block).toMatch(/if \(await applySettingsForResult\(\)\) \{\s*\n\s*closeSettings\(\);/);
+  });
+
+  it("surfaces persistence failures instead of silently swallowing them", () => {
+    const resultBlock = dialogSource.slice(dialogSource.indexOf("async function applySettingsForResult()"), dialogSource.indexOf("async function applySettings()"));
+    expect(resultBlock).toContain("try {");
+    expect(resultBlock).toContain("catch (error)");
+    expect(resultBlock).toContain("applySettingsErrorToast(error)");
+    expect(resultBlock).toContain("return false;");
+    // a user-facing message is wired up (and translated in every locale)
+    expect(dialogSource).toContain('toast(t("settings.applyFailed"');
+  });
+});