From 2e9903c203939fc6224ab1a2f254b264d53a2529 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?V=C3=ADt=20Ondruch?= <vondruch@redhat.com>
Date: Fri, 14 Aug 2026 13:43:54 +0200
Subject: [PATCH] Don't use RegExp match for `substring-after()` XPath function

XPath expects `string` match according to specification:

https://www.w3.org/TR/1999/REC-xpath-19991116/#function-substring-after

So these two should not provide the same result (while they previously
did):

~~~
REXML::Functions::substring_after("helloworld","hello")
REXML::Functions::substring_after("helloworld","hel.o")
~~~
---
 lib/rexml/functions.rb      | 9 +++++++--
 test/functions/test_base.rb | 2 ++
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/lib/rexml/functions.rb b/lib/rexml/functions.rb
index 106a21ee..f84b846b 100644
--- a/lib/rexml/functions.rb
+++ b/lib/rexml/functions.rb
@@ -205,8 +205,13 @@ def substring_before( string, test )
     # Kouhei fixed this too
     def substring_after( string, test )
       ruby_string = string(string)
-      return $1 if ruby_string =~ /#{test}(.*)/
-      ""
+      ruby_test = string(test)
+      ruby_index = ruby_string.index(ruby_test)
+      if ruby_index.nil?
+        ""
+      else
+        ruby_string[(ruby_index + ruby_test.length)..-1]
+      end
     end
 
     # Take equal portions of Mike Stok and Sean Russell; mix
diff --git a/test/functions/test_base.rb b/test/functions/test_base.rb
index 44f07c11..b63f3d5a 100644
--- a/test/functions/test_base.rb
+++ b/test/functions/test_base.rb
@@ -126,6 +126,8 @@ def test_substring
     def test_substring_angrez
       testString = REXML::Functions::substring_after("helloworld","hello")
       assert_equal( 'world', testString )
+      testString = REXML::Functions::substring_after("helloworld","hel.o")
+      assert_equal( '', testString )
     end
 
     def test_translate