Catch and log errors setting local storage values.

r2/r2/public/static/js/base.js

@@ -36,6 +36,35 @@ r.ajax = function(request) {
     return $.ajax(request)
 }
 
+store.safeGet = function(key, errorValue) {
+    // errorValue defaults to undefined, equivalent to the key being unset.
+    try {
+        return store.get(key)
+    } catch (err) {
+        r.sendError('Unable to read storage key "%(key)s" (%(err)s)'.format({
+            key: key,
+            err: err
+        }))
+        // TODO: reset value to errorValue?
+        return errorValue
+    }
+}
+
+store.safeSet = function(key, val) {
+    // swallow exceptions upon storage set for non-trivial operations. returns
+    // a boolean value indicating success.
+    try {
+        store.set(key, val)
+        return true
+    } catch (err) {
+        r.warn('Unable to set storage key "%(key)s" (%(err)s)'.format({
+            key: key,
+            err: err
+        }))
+        return false
+    }
+}
+
 r.setupBackbone = function() {
     Backbone.emulateJSON = true
     Backbone.ajax = r.ajax

r2/r2/public/static/js/multi.js

@@ -610,9 +610,9 @@ r.multi.ListingChooser = Backbone.View.extend({
         this.$el.addClass('initialized')
 
         // transition collapsed state to server pref
-        if (store.get('ui.collapse.listingchooser') == true) {
+        if (store.safeGet('ui.collapse.listingchooser') == true) {
             this.toggleCollapsed(true)
-            store.remove('ui.collapse.listingchooser')
+            store.safeSet('ui.collapse.listingchooser')
         }
 
         // HACK: fudge page heights for long lists of multis / short pages

r2/r2/public/static/js/ui.js

@@ -3,10 +3,10 @@ r.ui.init = function() {
     if ($.cookie('reddit_first')) {
         // save welcome seen state and delete obsolete cookie
         $.cookie('reddit_first', null, {domain: r.config.cur_domain})
-        store.set('ui.shown.welcome', true)
-    } else if (store.get('ui.shown.welcome') != true) {
+        store.safeSet('ui.shown.welcome', true)
+    } else if (store.safeGet('ui.shown.welcome') != true) {
         $('.infobar.welcome').show()
-        store.set('ui.shown.welcome', true)
+        store.safeSet('ui.shown.welcome', true)
     }
 
     // mobile suggest infobar

r2/r2/public/static/js/uibase.js

@@ -13,7 +13,7 @@ r.ui.Collapse = function(el, target, key) {
     r.ui.Base.call(this, el)
     this.target = target
     this.key = 'ui.collapse.' + key
-    this.isCollapsed = store.get(this.key) == true
+    this.isCollapsed = store.safeGet(this.key) == true
     this.$el.click($.proxy(this, 'toggle', null, false))
     this.toggle(this.isCollapsed, true)
 }
@@ -33,7 +33,7 @@ r.ui.Collapse.prototype = {
         }
 
         this.isCollapsed = collapsed
-        store.set(this.key, collapsed)
+        store.safeSet(this.key, collapsed)
         this.update()
     },