From fa53ccb30c257058529b4904493b8ba011b9dc76 Mon Sep 17 00:00:00 2001
From: Janusz Kaczmarek <januszop@gmail.com>
Date: Wed, 22 Feb 2023 15:45:20 +0100
Subject: [PATCH] Bug 28884: ElasticSearch: Question mark in title search
 returns no results
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1. It happens that question mark (‘?’) is contained in bibliographic
data (e.g. in title).

2. It happens that user perform searches with that contain question
mark (e.g. searching with a title taken verbatim).

3. In ES queries, in particular in query_string query, question
mark has a special meaning – substitutes one character
(https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-query-string-query.html#query-string-wildcard).
Question mark has also special meaning in regexp inside
quiery_string
(https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-query-string-query.html#_regular_expressions).

4. Ordinary users are not aware of this special function of the
question mark and, as a result, receive no results (e.g.
while searching for title like "Will libraries survive? :
the future of public libraries").

Test plan:
==========
1. Have biblio record with title like
   245 10 $a Will libraries survive? : $b the future of public libraries.
   (= with question mark attached to a word) in Koha instance with ES.
2. Search for: Will libraries survive? the future of public libraries
   You should get no results.
3. Apply the patch, controll that QueryRegexEscapeOptions is set to
   Escape.
4. Repeat the search.  You should get the record.
---
 Koha/SearchEngine/Elasticsearch/QueryBuilder.pm | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Koha/SearchEngine/Elasticsearch/QueryBuilder.pm b/Koha/SearchEngine/Elasticsearch/QueryBuilder.pm
index 53042b4303..6e37ab4829 100644
--- a/Koha/SearchEngine/Elasticsearch/QueryBuilder.pm
+++ b/Koha/SearchEngine/Elasticsearch/QueryBuilder.pm
@@ -1033,13 +1033,13 @@ sub _query_regex_escape_process {
             # replaced with a more general parser solution
             # so that this function is ever only provided with unquoted
             # query parts
-            $query =~ s@(?:(?<!\\)((?:[\\]{2})*)(?=/))(?![^"]*"(?:[^"]*"[^"]*")*[^"]*$)@\\$1@g;
+            $query =~ s@(?:(?<!\\)((?:[\\]{2})*)(?=[/\?]))(?![^"]*"(?:[^"]*"[^"]*")*[^"]*$)@\\$1@g;
         }
         elsif($regex_escape_options eq 'unescape_escaped') {
             # Will unescape escaped slashes (\/) and escape
             # unescaped slashes (/) while preserving slashes within quotes
             # The same limitatations as above apply for handling of quotes
-            $query =~ s@(?:(?<!\\)(?:((?:[\\]{2})*[\\])|((?:[\\]{2})*))(?=/))(?![^"]*"(?:[^"]*"[^"]*")*[^"]*$)@($1 ? substr($1, 0, -1) : ($2 . "\\"))@ge;
+            $query =~ s@(?:(?<!\\)(?:((?:[\\]{2})*[\\])|((?:[\\]{2})*))(?=[/\?]))(?![^"]*"(?:[^"]*"[^"]*")*[^"]*$)@($1 ? substr($1, 0, -1) : ($2 . "\\"))@ge;
         }
     }
     return $query;
-- 
2.30.2