From 47a7575eaa1b65f0bdc2d8469fa0814b0cbfb0d6 Mon Sep 17 00:00:00 2001
From: Antoine Lambert <anlambert@softwareheritage.org>
Date: Wed, 11 Dec 2024 15:08:16 +0100
Subject: [PATCH] Fix parsing of xml-stylesheet as first processing instruction

If xml-stylesheet is the first processing instruction in the document
to parse, it was incorrectly parsed as a xml processing instruction.
---
 src/index.ts  |  2 +-
 test/index.ts | 24 ++++++++++++++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/src/index.ts b/src/index.ts
index b9dae14..0c64879 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -129,7 +129,7 @@ function parseDocument(): XmlParserResult {
 }
 
 function processingInstruction(matchDeclaration: boolean): XmlParserNodeWrapper<XmlParserProcessingInstructionNode>|undefined {
-    const m = matchDeclaration ? match(/^<\?(xml)\s*/) : match(/^<\?([\w-:.]+)\s*/);
+    const m = matchDeclaration ? match(/^<\?(xml(-stylesheet)?)\s*/) : match(/^<\?([\w-:.]+)\s*/);
     if (!m) return;
 
     // tag
diff --git a/test/index.ts b/test/index.ts
index b4e240d..ca8dbbc 100644
--- a/test/index.ts
+++ b/test/index.ts
@@ -580,6 +580,30 @@ describe('XML Parser', function() {
         });
     });
 
+    it('should correctly parse xml-stylesheet as first processing instruction', function() {
+        const node = xmlParser('<?xml-stylesheet href="style.xsl" type="text/xsl" ?><foo></foo>');
+
+        const root: XmlParserElementNode = {
+            type: 'Element',
+            name: 'foo',
+            attributes: {},
+            children: []
+        };
+
+        assert.deepEqual(node, {
+            declaration: {
+                name: 'xml-stylesheet',
+                type: 'ProcessingInstruction',
+                attributes: {
+                    href: 'style.xsl',
+                    type: 'text/xsl'
+                }
+            },
+            root: root,
+            children: [root]
+        });
+    });
+
     it('should support complex XML', function() {
         const node = xmlParser(`<?xml version="1.0" encoding="utf-8"?>
 <!-- Load the stylesheet -->