From 2c8533f38e854adfc50bf7d03f3d213985ccbe52 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Simon=20W=C3=BClker?= <simon.wuelker@arcor.de>
Date: Sun, 21 Sep 2025 05:45:04 +0200
Subject: [PATCH] Parse qualified names with non-alpha characters in xpath
 (#39409)
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The existing parsing rules are too strict and only allow alpha and
alphanumeric characters. Instead, we should follow the production
defined in https://www.w3.org/TR/REC-xml-names/#NT-NCName.

Testing: New tests start to pass
Part of https://github.com/servo/servo/issues/34527

---------

Signed-off-by: Simon Wülker <simon.wuelker@arcor.de>
---
 components/script/xpath/parser.rs             | 38 ++++++++++++++-----
 .../domxpath/text-html-attributes.html.ini    | 12 ------
 .../meta/domxpath/text-html-elements.html.ini |  3 --
 3 files changed, 29 insertions(+), 24 deletions(-)

diff --git a/components/script/xpath/parser.rs b/components/script/xpath/parser.rs
index f1f38ea0da5..699c9bf235a 100644
--- a/components/script/xpath/parser.rs
+++ b/components/script/xpath/parser.rs
@@ -4,12 +4,14 @@
 
 use nom::branch::alt;
 use nom::bytes::complete::{tag, take_while1};
-use nom::character::complete::{alpha1, alphanumeric1, char, digit1, multispace0};
+use nom::character::complete::{char, digit1, multispace0};
 use nom::combinator::{map, opt, recognize, value};
 use nom::error::{Error as NomError, ErrorKind as NomErrorKind, ParseError as NomParseError};
 use nom::multi::{many0, separated_list0};
 use nom::sequence::{delimited, pair, preceded};
-use nom::{Finish, IResult, Parser};
+use nom::{AsChar, Finish, IResult, Input, Parser};
+
+use crate::dom::bindings::xmlname::{is_valid_continuation, is_valid_start};
 
 pub(crate) fn parse(input: &str) -> Result<Expr, OwnedParserError> {
     let (_, ast) = expr(input).finish().map_err(OwnedParserError::from)?;
@@ -955,7 +957,7 @@ fn string_literal(input: &str) -> IResult<&str, Literal> {
     .parse(input)
 }
 
-// QName parser
+/// <https://www.w3.org/TR/REC-xml-names/#NT-QName>
 fn qname(input: &str) -> IResult<&str, QName> {
     let (input, prefix) = opt((ncname, char(':'))).parse(input)?;
     let (input, local) = ncname(input)?;
@@ -969,13 +971,31 @@ fn qname(input: &str) -> IResult<&str, QName> {
     ))
 }
 
-// NCName parser
+/// <https://www.w3.org/TR/REC-xml-names/#NT-NCName>
 fn ncname(input: &str) -> IResult<&str, &str> {
-    recognize(pair(
-        alpha1,
-        many0(alt((alphanumeric1, tag("-"), tag("_")))),
-    ))
-    .parse(input)
+    fn name_start_character<T, E: NomParseError<T>>(input: T) -> IResult<T, T, E>
+    where
+        T: Input,
+        <T as Input>::Item: AsChar,
+    {
+        input.split_at_position1_complete(
+            |character| !is_valid_start(character.as_char()) || character.as_char() == ':',
+            NomErrorKind::OneOf,
+        )
+    }
+
+    fn name_character<T, E: NomParseError<T>>(input: T) -> IResult<T, T, E>
+    where
+        T: Input,
+        <T as Input>::Item: AsChar,
+    {
+        input.split_at_position1_complete(
+            |character| !is_valid_continuation(character.as_char()) || character.as_char() == ':',
+            NomErrorKind::OneOf,
+        )
+    }
+
+    recognize(pair(name_start_character, many0(name_character))).parse(input)
 }
 
 // Test functions to verify the parsers:
diff --git a/tests/wpt/meta/domxpath/text-html-attributes.html.ini b/tests/wpt/meta/domxpath/text-html-attributes.html.ini
index 22dc2e57ac1..de4111d0cec 100644
--- a/tests/wpt/meta/domxpath/text-html-attributes.html.ini
+++ b/tests/wpt/meta/domxpath/text-html-attributes.html.ini
@@ -2,20 +2,8 @@
   [Select html element based on attribute mixed case]
     expected: FAIL
 
-  [Select HTML element with non-ascii attribute 1]
-    expected: FAIL
-
-  [Select HTML element with non-ascii attribute 2]
-    expected: FAIL
-
   [Select HTML element with non-ascii attribute 3]
     expected: FAIL
 
   [Select both HTML and SVG elements based on mixed case attribute]
     expected: FAIL
-
-  [Select SVG element with non-ascii attribute 1]
-    expected: FAIL
-
-  [Select SVG element with non-ascii attribute 2]
-    expected: FAIL
diff --git a/tests/wpt/meta/domxpath/text-html-elements.html.ini b/tests/wpt/meta/domxpath/text-html-elements.html.ini
index 5fdd314b4c7..dfac96a8954 100644
--- a/tests/wpt/meta/domxpath/text-html-elements.html.ini
+++ b/tests/wpt/meta/domxpath/text-html-elements.html.ini
@@ -2,9 +2,6 @@
   [HTML elements mixed case]
     expected: FAIL
 
-  [Non-ascii HTML element]
-    expected: FAIL
-
   [Non-ascii HTML element3]
     expected: FAIL