Add a patch to make searchtools.js support pre-4.3 search indexes.

Sphinx 4.3 has changed format of searchindex.js files, but in Debian
there are lots of packages built with older Sphinx, and we want to
keep them working for some time.

debian/changelog

@@ -4,6 +4,7 @@ sphinx (4.3.1-2) UNRELEASED; urgency=medium
     - Stop taking Python 2 version of alabaster into account.
     - Generate dependency on libjs-sphinxdoc ≥ 4.3 for searchtools.js.
     - Loosen regex to detect searchindex.js loading (closes: #1001521).
+  * Add a patch to make searchtools.js support pre-4.3 search indexes.
 
  -- Dmitry Shachnev <mitya57@debian.org>  Sun, 28 Nov 2021 16:38:01 +0300
 

debian/patches/series

@@ -8,3 +8,4 @@ use_packaged_mathjax.diff
 skip_tests_serializinghtml.diff
 move_sphinxcontrib_to_extras_require.diff
 intersphinx_local.diff
+support_old_search_indexes.diff

debian/patches/support_old_search_indexes.diff

+From: Dmitry Shachnev <mitya57@debian.org>
+Date: Sat, 11 Dec 2021 19:19:27 +0300
+Subject: Make searchtools.js support old searchindex.js files
+
+Sphinx 4.3 has changed format of searchindex.js files, but in Debian
+there are lots of packages built with older Sphinx, and we want to
+keep them working for some time.
+
+Forwarded: not-needed
+---
+ sphinx/themes/basic/static/searchtools.js | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/sphinx/themes/basic/static/searchtools.js b/sphinx/themes/basic/static/searchtools.js
+index 002e9c4..7dbc787 100644
+--- a/sphinx/themes/basic/static/searchtools.js
++++ b/sphinx/themes/basic/static/searchtools.js
+@@ -328,6 +328,9 @@ var Search = {
+     var results = [];
+ 
+     for (var prefix in objects) {
++      if (!(objects[prefix] instanceof Array)) {
++        objects[prefix] = Object.entries(objects[prefix]).map(([name, match]) => [...match, name]);
++      }
+       for (var iMatch = 0; iMatch != objects[prefix].length; ++iMatch) {
+         var match = objects[prefix][iMatch];
+         var name = match[4];