From fd36729e0679e08f167965ceec7c2a336f5ae211 Mon Sep 17 00:00:00 2001
From: Trevor Burnham <trevorburnham@gmail.com>
Date: Fri, 6 Mar 2026 14:12:04 -0500
Subject: [PATCH] fix: sync sourceCodeLocation.attrs keys with adjusted
 SVG/MathML/XML attribute names

When parsing foreign content (SVG, MathML), attribute names are adjusted
from lowercase to their spec-correct casing (e.g. viewbox -> viewBox).
The location info keys in token.location.attrs were not updated to match,
causing a mismatch where attrs[i].name and Object.keys(location.attrs)
would differ.

Fixes #318
---
 packages/parse5/lib/common/foreign-content.ts | 10 ++++
 .../lib/parser/parser-location-info.test.ts   | 47 +++++++++++++++++++
 2 files changed, 57 insertions(+)

diff --git a/packages/parse5/lib/common/foreign-content.ts b/packages/parse5/lib/common/foreign-content.ts
index 464e65c7e..b721e2d65 100644
--- a/packages/parse5/lib/common/foreign-content.ts
+++ b/packages/parse5/lib/common/foreign-content.ts
@@ -188,9 +188,17 @@ export function causesExit(startTagToken: TagToken): boolean {
 }
 
 //Token adjustments
+function adjustTokenAttrLocation(token: TagToken, oldName: string, newName: string): void {
+    if (token.location?.attrs) {
+        token.location.attrs[newName] = token.location.attrs[oldName];
+        delete token.location.attrs[oldName];
+    }
+}
+
 export function adjustTokenMathMLAttrs(token: TagToken): void {
     for (let i = 0; i < token.attrs.length; i++) {
         if (token.attrs[i].name === DEFINITION_URL_ATTR) {
+            adjustTokenAttrLocation(token, DEFINITION_URL_ATTR, ADJUSTED_DEFINITION_URL_ATTR);
             token.attrs[i].name = ADJUSTED_DEFINITION_URL_ATTR;
             break;
         }
@@ -202,6 +210,7 @@ export function adjustTokenSVGAttrs(token: TagToken): void {
         const adjustedAttrName = SVG_ATTRS_ADJUSTMENT_MAP.get(token.attrs[i].name);
 
         if (adjustedAttrName != null) {
+            adjustTokenAttrLocation(token, token.attrs[i].name, adjustedAttrName);
             token.attrs[i].name = adjustedAttrName;
         }
     }
@@ -212,6 +221,7 @@ export function adjustTokenXMLAttrs(token: TagToken): void {
         const adjustedAttrEntry = XML_ATTRS_ADJUSTMENT_MAP.get(token.attrs[i].name);
 
         if (adjustedAttrEntry) {
+            adjustTokenAttrLocation(token, token.attrs[i].name, adjustedAttrEntry.name);
             token.attrs[i].prefix = adjustedAttrEntry.prefix;
             token.attrs[i].name = adjustedAttrEntry.name;
             token.attrs[i].namespace = adjustedAttrEntry.namespace;
diff --git a/packages/parse5/lib/parser/parser-location-info.test.ts b/packages/parse5/lib/parser/parser-location-info.test.ts
index 0fdb15c49..f013da787 100644
--- a/packages/parse5/lib/parser/parser-location-info.test.ts
+++ b/packages/parse5/lib/parser/parser-location-info.test.ts
@@ -156,6 +156,53 @@ generateTestsForEachTreeAdapter('location-info-parser', (treeAdapter) => {
         );
     });
 
+    it('Regression - SVG attribute location keys should match adjusted camelCase names (GH-318)', () => {
+        const html = '<svg viewBox="0 0 100 100"></svg>';
+
+        const opts = {
+            treeAdapter,
+            sourceCodeLocationInfo: true,
+        };
+
+        const fragment = parseFragment(html, opts);
+        const svg = treeAdapter.getChildNodes(fragment)[0];
+        const location = treeAdapter.getNodeSourceCodeLocation(svg);
+        const attrs = treeAdapter.getAttrList(svg);
+
+        assert.ok(location?.attrs);
+
+        // The attrs array should have the camelCase name
+        const viewBoxAttr = attrs.find((a) => a.name === 'viewBox');
+        assert.ok(viewBoxAttr, 'attrs should contain viewBox with camelCase name');
+
+        // The location attrs should use the same camelCase key
+        assert.ok(location.attrs['viewBox'], 'location.attrs should have camelCase key "viewBox"');
+        assert.ok(!location.attrs['viewbox'], 'location.attrs should not have lowercase key "viewbox"');
+    });
+
+    it('Regression - MathML definitionURL attribute location key should match adjusted name (GH-318)', () => {
+        const html = '<math><mprescripts definitionURL="http://example.com"></mprescripts></math>';
+
+        const opts = {
+            treeAdapter,
+            sourceCodeLocationInfo: true,
+        };
+
+        const fragment = parseFragment(html, opts);
+        const math = treeAdapter.getChildNodes(fragment)[0];
+        const mprescripts = treeAdapter.getChildNodes(math)[0];
+        const location = treeAdapter.getNodeSourceCodeLocation(mprescripts);
+        const attrs = treeAdapter.getAttrList(mprescripts);
+
+        assert.ok(location?.attrs);
+
+        const attr = attrs.find((a) => a.name === 'definitionURL');
+        assert.ok(attr, 'attrs should contain definitionURL');
+
+        assert.ok(location.attrs['definitionURL'], 'location.attrs should have "definitionURL"');
+        assert.ok(!location.attrs['definitionurl'], 'location.attrs should not have "definitionurl"');
+    });
+
     it('Regression - Escaped script content has incorrect location info (GH-265)', () => {
         const html = '<script>"<!--";</script>';