Gracefully handle failures to access localStorage (#12682)

A follow up PR resolving [PR
comments](#12673 (comment))
on #12673 by Gemini code assist.

---------

Co-authored-by: Parker Lougheed <[email protected]>

Author: dixita0607

site/lib/src/client/global_scripts.dart

@@ -117,10 +117,16 @@ void _setUpTabs() {
           // If the tab wrapper and this tab have a save key and ID defined,
           // switch other tabs to the tab with the same ID.
           _findAndActivateTabsWithSaveId(currentSaveKey, currentSaveId);
-          web.window.localStorage.setItem(
-            'tab-save-$currentSaveKey',
-            currentSaveId,
-          );
+          try {
+            web.window.localStorage.setItem(
+              'tab-save-$currentSaveKey',
+              currentSaveId,
+            );
+          } catch (e) {
+            if (kDebugMode) {
+              print('Error accessing localStorage: $e');
+            }
+          }
         } else {
           _clearActiveTabs(tabs);
           _setActiveTab(tabElement);
@@ -129,12 +135,19 @@ void _setUpTabs() {
 
       tabElement.addEventListener('click', handleClick.toJS);
 
-      // If a tab was previously specified as selected in local storage,
-      // save a reference to it that can be switched to later.
-      if (saveId.isNotEmpty &&
-          localStorageKey != null &&
-          web.window.localStorage.getItem(localStorageKey) == saveId) {
-        tabToChangeTo = tabElement;
+      try {
+        // If a tab was previously specified as selected in local storage,
+        // save a reference to it that can be switched to later.
+        final tabSaveKey = localStorageKey != null
+            ? web.window.localStorage.getItem(localStorageKey)
+            : null;
+        if (saveId.isNotEmpty && tabSaveKey != null && tabSaveKey == saveId) {
+          tabToChangeTo = tabElement;
+        }
+      } catch (e) {
+        if (kDebugMode) {
+          print('Error accessing localStorage: $e');
+        }
       }
     }
 
@@ -165,8 +178,14 @@ void _updateTabsFromQueryParameters() {
 
   for (final MapEntry(:key, :value) in originalQueryParameters.entries) {
     if (key.startsWith('tab-save-')) {
-      web.window.localStorage.setItem(key, value);
-      updatedQueryParameters.remove(key);
+      try {
+        web.window.localStorage.setItem(key, value);
+        updatedQueryParameters.remove(key);
+      } catch (e) {
+        if (kDebugMode) {
+          print('Error accessing localStorage: $e');
+        }
+      }
     }
   }
 

site/lib/src/components/common/client/cookie_notice.dart

@@ -26,18 +26,28 @@ final class _CookieNoticeState extends State<CookieNotice> {
   void initState() {
     if (kIsWeb) {
       var shouldShowNotice = true;
-      if (web.window.localStorage.getItem(_cookieStorageKey)
-          case final lastConsentedMs?) {
-        if (int.tryParse(lastConsentedMs) case final msFromEpoch?) {
-          final consentedDateTime = DateTime.fromMillisecondsSinceEpoch(
-            msFromEpoch,
-          );
-          final difference = consentedDateTime.difference(DateTime.now());
-          if (difference.inDays < 180) {
-            // If consented less than 180 days ago, don't show the notice.
-            shouldShowNotice = false;
+      try {
+        final storedConsent = web.window.localStorage.getItem(
+          _cookieStorageKey,
+        );
+        if (storedConsent case final lastConsentedMs?) {
+          if (int.tryParse(lastConsentedMs) case final msFromEpoch?) {
+            final consentedDateTime = DateTime.fromMillisecondsSinceEpoch(
+              msFromEpoch,
+            );
+            final difference = consentedDateTime.difference(DateTime.now());
+            if (difference.inDays < 180) {
+              // If consented less than 180 days ago, don't show the notice.
+              shouldShowNotice = false;
+            }
           }
         }
+      } catch (e) {
+        // If localStorage is unavailable or throws an error,
+        // keep the `shouldShowNotice` to true.
+        if (kDebugMode) {
+          print('Failed to get stored content: $e');
+        }
       }
 
       showNotice = shouldShowNotice;
@@ -69,10 +79,16 @@ final class _CookieNoticeState extends State<CookieNotice> {
               content: 'OK, got it',
               style: ButtonStyle.filled,
               onClick: () {
-                web.window.localStorage.setItem(
-                  _cookieStorageKey,
-                  DateTime.now().millisecondsSinceEpoch.toString(),
-                );
+                try {
+                  web.window.localStorage.setItem(
+                    _cookieStorageKey,
+                    DateTime.now().millisecondsSinceEpoch.toString(),
+                  );
+                } catch (e) {
+                  if (kDebugMode) {
+                    print('Failed to set stored consent: $e');
+                  }
+                }
                 setState(() {
                   showNotice = false;
                 });

site/lib/src/components/layout/theme_switcher.dart

@@ -73,7 +73,13 @@ final class _ThemeSwitcherState extends State<ThemeSwitcher> {
       );
     }
 
-    web.window.localStorage.setItem('theme', newTheme.id);
+    try {
+      web.window.localStorage.setItem('theme', newTheme.id);
+    } catch (e) {
+      if (kDebugMode) {
+        print('Failed to save theme preference: $e');
+      }
+    }
 
     setState(() {
       _currentTheme = newTheme;

site/lib/src/layouts/dash_layout.dart

@@ -171,16 +171,19 @@ ga('send', 'pageview');
         // avoid a flash of the initial theme on load.
         raw('''
 <script>
-const prefersDarkMode = window.matchMedia('(prefers-color-scheme: dark)');
-
-const storedTheme = window.localStorage.getItem('theme') ?? 'light-mode';
-if (storedTheme === 'auto-mode') {
-  document.body.classList.add(
-      'auto-mode',
-      prefersDarkMode.matches ? 'dark-mode' : 'light-mode',
-  );
-} else {
-  document.body.classList.add(storedTheme);
+try {
+  const storedTheme = window.localStorage.getItem('theme') ?? 'light-mode';
+  if (storedTheme === 'auto-mode') {
+    const prefersDarkMode = window.matchMedia('(prefers-color-scheme: dark)');
+    document.body.classList.add(
+        'auto-mode',
+        prefersDarkMode.matches ? 'dark-mode' : 'light-mode',
+    );
+  } else {
+    document.body.classList.add(storedTheme);
+  }
+} catch (e) {
+  // localStorage is not available, do nothing and fall back to default.
 }
 </script>
       '''),