rustdoc: Enforce theme actually exists

Author: Chad Norvell

src/librustdoc/html/static/js/storage.js

@@ -109,6 +109,13 @@ const getVar = (function getVar(name) {
 });
 
 function switchTheme(newThemeName, saveTheme) {
+    const theme_names = getVar("themes").split(",").filter(t => t);
+    theme_names.push("light", "dark", "ayu");
+
+    if (theme_names.indexOf(newThemeName) == -1) {
+        return;
+    }
+
     // If this new value comes from a system setting or from the previously
     // saved theme, no need to save it.
     if (saveTheme) {
@@ -123,7 +130,7 @@ function switchTheme(newThemeName, saveTheme) {
             window.currentTheme = null;
         }
     } else {
-        const newHref = getVar("root-path") + newThemeName +
+        const newHref = getVar("root-path") + encodeURIComponent(newThemeName) +
             getVar("resource-suffix") + ".css";
         if (!window.currentTheme) {
             // If we're in the middle of loading, document.write blocks