From 7f7bdb3417a043e2acb3c17e070960071dcea02e Mon Sep 17 00:00:00 2001
From: Michael Becker <michael.becker@uni-leipzig.de>
Date: Mon, 6 Jul 2026 10:52:03 +0200
Subject: [PATCH] MCR-3757 use xml:lang instead of lang() for classification
 label selection

---
 .../main/resources/xslt/functions/classification.xsl | 12 ++++++------
 .../frontend/xsl/MCRXSLClassificationTest.java       |  2 +-
 .../resources/classification/TestClassification.xml  |  1 +
 3 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/mycore-base/src/main/resources/xslt/functions/classification.xsl b/mycore-base/src/main/resources/xslt/functions/classification.xsl
index 7b80d7a07a..e906e33da2 100644
--- a/mycore-base/src/main/resources/xslt/functions/classification.xsl
+++ b/mycore-base/src/main/resources/xslt/functions/classification.xsl
@@ -47,14 +47,14 @@
       <xsl:when test="$class[@classid and @categid]">
         <xsl:sequence select="mcrclass:label($lang, document(concat('classification:metadata:0:children:',$class/@classid,':',$class/@categid))//category)" />
       </xsl:when>
-      <xsl:when test="string-length($lang) > 0 and $class/label[lang($lang)]">
-        <xsl:sequence select="$class/label[lang($lang)]" />
+      <xsl:when test="string-length($lang) > 0 and $class/label[@xml:lang = $lang]">
+        <xsl:sequence select="$class/label[@xml:lang = $lang]" />
       </xsl:when>
-      <xsl:when test="$class/label[lang($CurrentLang)]">
-        <xsl:sequence select="$class/label[lang($CurrentLang)]" />
+      <xsl:when test="$class/label[@xml:lang = $CurrentLang]">
+        <xsl:sequence select="$class/label[@xml:lang = $CurrentLang]" />
       </xsl:when>
-      <xsl:when test="$class/label[lang($DefaultLang)]">
-        <xsl:sequence select="$class/label[lang($DefaultLang)]" />
+      <xsl:when test="$class/label[@xml:lang = $DefaultLang]">
+        <xsl:sequence select="$class/label[@xml:lang = $DefaultLang]" />
       </xsl:when>
       <xsl:otherwise>
         <xsl:sequence select="$class/label[1]" />
diff --git a/mycore-base/src/test/java/org/mycore/frontend/xsl/MCRXSLClassificationTest.java b/mycore-base/src/test/java/org/mycore/frontend/xsl/MCRXSLClassificationTest.java
index 9073325153..bea906be61 100644
--- a/mycore-base/src/test/java/org/mycore/frontend/xsl/MCRXSLClassificationTest.java
+++ b/mycore-base/src/test/java/org/mycore/frontend/xsl/MCRXSLClassificationTest.java
@@ -45,7 +45,7 @@ public void testCategory() throws Exception {
         // existing classification: return category with respective labels
         assertEquals(1, result.getChildren("category").size());
         assertEquals("junit_1", result.getChild("category").getAttributeValue("ID"));
-        assertEquals(3, result.getChild("category").getChildren("label").size());
+        assertEquals(4, result.getChild("category").getChildren("label").size());
         assertEquals("de",
             result.getChild("category").getChildren("label").get(0).getAttributeValue("lang", Namespace.XML_NAMESPACE));
         assertEquals("junit_1 (de)",
diff --git a/mycore-base/src/test/resources/classification/TestClassification.xml b/mycore-base/src/test/resources/classification/TestClassification.xml
index dfaa599b49..0f7d95ae68 100644
--- a/mycore-base/src/test/resources/classification/TestClassification.xml
+++ b/mycore-base/src/test/resources/classification/TestClassification.xml
@@ -6,6 +6,7 @@
             <label xml:lang="de" text="junit_1 (de)"/>
             <label xml:lang="en" text="junit_1 (en)"/>
             <label xml:lang="x-xxx" text="abc"/>
+            <label xml:lang="x-xxx-abc" text="def"/>
         </category>
         <category ID="junit_2">
             <label xml:lang="en" text="junit_2 (en)"/>