From 0d7e9a2687a36626c10c30bb5f2f43100569fef7 Mon Sep 17 00:00:00 2001
From: Pierre Labastie <pierre.labastie@neuf.fr>
Date: Sat, 20 Jan 2024 08:24:10 +0100
Subject: [PATCH] Fix output of anchors with same id in sect3

The template for sect3.titlepage generates:
<h3 class="sect3">
  <a id="{id of sect3}" name="{id of sect3}"></a>
  <h4 class="title">
    <a id="{id of sect3}" name="{id of sect3}">i{title of sect3}</a>
  </h4>
</h3>
resulting in double definition of the same id, which is a validity error
in XML documents.
Replace with the same template as for sect2, using h3 instead of h2.
---
 stylesheets/lfs-xsl/xhtml/lfs-titles.xsl | 30 +++++++++++++-----------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/stylesheets/lfs-xsl/xhtml/lfs-titles.xsl b/stylesheets/lfs-xsl/xhtml/lfs-titles.xsl
index c03bf26350..a82a3a99f7 100644
--- a/stylesheets/lfs-xsl/xhtml/lfs-titles.xsl
+++ b/stylesheets/lfs-xsl/xhtml/lfs-titles.xsl
@@ -127,23 +127,25 @@
   </xsl:template>
 
     <!-- sect3.titlepage:
-           Uses h3 and removed a lot of unneeded code.
-           Use generic titlepage.mode template in case there are child
-            elements (xref)-->
+         Same as sect2 except it uses h3 -->
     <!-- The original template is in {docbook-xsl}/xhtml/titlepage.templates.xsl -->
   <xsl:template name="sect3.titlepage">
-    <h3 class="{name(.)}">
-      <xsl:if test="@id">
-        <a id="{@id}" name="{@id}"/>
-      </xsl:if>
-      <xsl:if test="$section.autolabel != 0">
-        <xsl:apply-templates select="." mode="label.markup"/>
-        <xsl:text>. </xsl:text>
-      </xsl:if>
-      <xsl:apply-templates select="./title" mode="titlepage.mode"/>
-    </h3>
+    <xsl:choose>
+      <xsl:when test="string-length(title) = 0"/>
+      <xsl:otherwise>
+        <h3 class="{name(.)}">
+          <xsl:if test="@id">
+            <a id="{@id}" name="{@id}"/>
+          </xsl:if>
+          <xsl:if test="not(ancestor::preface) and $section.autolabel != 0">
+            <xsl:apply-templates select="." mode="label.markup"/>
+            <xsl:text>. </xsl:text>
+          </xsl:if>
+          <xsl:value-of select="title"/>
+        </h3>
+      </xsl:otherwise>
+    </xsl:choose>
   </xsl:template>
-
     <!-- dedication.titlepage:
            Uses h2 and removed a lot of unneeded code. -->
     <!-- The original template is in {docbook-xsl}/xhtml/titlepage.templates.xsl -->