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Incorrect parsing of `<`angle brackets `>` as text characters

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
52/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Active
Tech stack
javascript
Domain
tooling

Research direction

Start by reproducing both examples with XMLParser.parse using preserveOrder, then inspect the parser entry point and the token/name handling reached by these inputs. Use XMLBuilder.build to verify the result. Done means invalid angle-bracket sequences remain text and valid XML structure is preserved in both cases.

Written by the indexing model from the issue text.

Description

Feature-Request
  • Are you running the latest version?
  • Have you included sample input, output, error, and expected output?
  • Have you checked if you are using correct configuration?
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  • Have you checked the docs for helpful APIs and examples?
Description

I encountered a case where a text content like <...> inside a tag is incorrectly handled by the parser. The parser tries to interpret this as a tag name and breaks the tree structure. This is also applicable to the symbol \U+2026 Horizontal Ellipsis

What does <...> mean?

In text, <...> usually means something has been intentionally left out. It’s a placeholder that implies omitted words, omitted text that isn’t being shown, quoted, or repeated

However, the . symbol can indeed be used in the XML tag name, but only if it is not the starting character (NameStartChar in spec). And the ellipsis symbol seems to be invalid for NameChar. Please look at the Names and Tokens section here https://www.w3.org/TR/xml/#sec-common-syn

Also, while writing this issue, I tried using only the angle bracket characters individually and saw strange behavior. I've described this below as a second case.

I assume that the correct parser behavior if the angle brackets don't form a valid tag name according to XML specification would be to leave the angle bracket characters in the #text element or escape them in entities.

Input
Code
const xmlParser = new XMLParser({
  preserveOrder: true,
  allowBooleanAttributes: true,
  ignoreAttributes: false,
  ignoreDeclaration: true,
});

const firstCase = `<?xml version="1.0"?>
<root>
  <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer pretium odio non ex hendrerit, eu convallis sapien ultricies <...> Sed sagittis at est auctor varius. Donec sit amet nibh sodales, varius nunc eu, tempus turpis. <...> Nulla gravida erat a tortor sollicitudin laoreet.</p>
  <foo></foo>
</root>`;

const secondCase = `<?xml version="1.0"?>
<root>
<p>if (1 < 3) return text;</p>
</root>
`;

const jObj = xmlParser.parse(firstCase); // check first and second case

const xmlBuilder = new XMLBuilder({
  ignoreAttributes: false,
  preserveOrder: true,
});
const xmlContent = xmlBuilder.build(jObj);
console.log(xmlContent);
Output
In the first case:
jObj 
[
  {
    "root": [
      {
        "p": [
          {
            "#text": "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer pretium odio non ex hendrerit, eu convallis sapien ultricies"
          },
          {
            "...": [
              {
                "#text": "Sed sagittis at est auctor varius. Donec sit amet nibh sodales, varius nunc eu, tempus turpis."
              },
              {
                "...": [
                  {
                    "#text": "Nulla gravida erat a tortor sollicitudin laoreet."
                  }
                ]
              },
              {
                "foo": []
              }
            ]
          }
        ]
      }
    ]
  }
]

<root><p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer pretium odio non ex hendrerit, eu convallis sapien ultricies<...>Sed sagittis at est auctor varius. Donec sit amet nibh sodales, varius nunc eu, tempus turpis.<...>Nulla gravida erat a tortor sollicitudin laoreet.</...><foo></foo></...></p></root>
In the second case:
jObj 
[
  {
    "root": [
      {
        "p": [
          {
            "#text": "if (1"
          },
          {
            "": [],
            ":@": {
              "@_3)": true,
              "@_return": true,
              "@_text;": true,
              "@_</p": true
            }
          }
        ]
      }
    ]
  }
]

<root><p>if (1< 3) return text; </p></></p></root>
expected data
In the first case:
<root><p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer pretium odio non ex hendrerit, eu convallis sapien ultricies <...> Sed sagittis at est auctor varius. Donec sit amet nibh sodales, varius nunc eu, tempus turpis. <...> Nulla gravida erat a tortor sollicitudin laoreet.</p><foo></foo></root>
In the second case:
<root><p>if (1 < 3) return text;</p></root>

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