From 6605bfbf7cdea86492b33070167634284af0ffe7 Mon Sep 17 00:00:00 2001
From: Santos Gallegos <stsewd@protonmail.com>
Date: Mon, 31 Jan 2022 19:07:51 -0500
Subject: [PATCH] Searchtools: don't assume that all themes define some
 elements

When retrieving a non-existent element, jQuery would still return an
object (kind of empty one, so method calls won't raise a null
exception), but now `getElementById` will return null and raise an
exception when trying to call a method on that value.

This mainly affects the rtd theme,
which completely overrides the search page
https://github.com/readthedocs/sphinx_rtd_theme/blob/d64dadf1ceec4f9ff6c1ca2d3ea4c3d0fdb0e8d2/sphinx_rtd_theme/search.html
---
 sphinx/themes/basic/static/searchtools.js | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/sphinx/themes/basic/static/searchtools.js b/sphinx/themes/basic/static/searchtools.js
index 943507508..35341f165 100644
--- a/sphinx/themes/basic/static/searchtools.js
+++ b/sphinx/themes/basic/static/searchtools.js
@@ -48,7 +48,7 @@ if (!Scorer) {
 }
 
 const _removeChildren = (element) => {
-  while (element.lastChild) element.removeChild(element.lastChild);
+  while (element && element.lastChild) element.removeChild(element.lastChild);
 };
 
 /**
@@ -208,9 +208,11 @@ const Search = {
     Search.status = out.appendChild(searchSummary);
     Search.output = out.appendChild(searchList);
 
-    document.getElementById("search-progress").innerText = _(
-      "Preparing search..."
-    );
+    const searchProgress = document.getElementById("search-progress");
+    // Not all themes may have this element.
+    if (searchProgress) {
+      searchProgress.innerText = _("Preparing search...");
+    }
     Search.startPulse();
 
     // index already loaded, the browser was quick!