Better concurrency handling for search JS script loading

src/librustdoc/html/render/write_shared.rs

@@ -328,8 +328,8 @@ pub(super) fn write_shared(
         v.push_str(
             r#"\
 ]'));
-if (typeof window !== 'undefined' && window.initSearch) {window.initSearch(searchIndex)};
-if (typeof exports !== 'undefined') {exports.searchIndex = searchIndex};
+if (typeof exports !== 'undefined') exports.searchIndex = searchIndex;
+else runSearchIfFullyLoaded();
 "#,
         );
         Ok(v.into_bytes())

src/librustdoc/html/static/js/main.js

@@ -188,6 +188,7 @@ function preLoadCss(cssUrl) {
     function loadScript(url) {
         const script = document.createElement("script");
         script.src = url;
+        script.setAttribute('async', '');
         document.head.append(script);
     }
 

src/librustdoc/html/static/js/search.js

@@ -3354,9 +3354,7 @@ ${item.displayPath}<span class="${type}">${name}</span>\
 
 if (typeof window !== "undefined") {
     window.initSearch = initSearch;
-    if (window.searchIndex !== undefined) {
-        initSearch(window.searchIndex);
-    }
+    runSearchIfFullyLoaded();
 } else {
     // Running in Node, not a browser. Run initSearch just to produce the
     // exports.

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

@@ -61,6 +61,15 @@ function onEach(arr, func) {
     return false;
 }
 
+let nbSearchScriptLoaded = 0;
+// eslint-disable-next-line no-unused-vars
+function runSearchIfFullyLoaded() {
+    nbSearchScriptLoaded += 1;
+    if (nbSearchScriptLoaded === 2) {
+        window.initSearch(window.searchIndex);
+    }
+}
+
 /**
  * Turn an HTMLCollection or a NodeList into an Array, then run a callback
  * for every element. This is useful because iterating over an HTMLCollection