[Enhancement - Definition] - Use AST offsets for reliable tag-pair navigation

[harshanacz]

Problem
The current doDefinition implementation uses text.indexOf() to find the matching closing tag. This is unreliable in complex XML files where identical tag names appear multiple times, as it may jump to the wrong tag. It is also less efficient than using the existing AST.

Proposed Solution
Refactor the logic to rely on the XMLNode structure rather than manual string searching.

Key Improvements:

• Direct Offset Mapping: Use node.endTagStartOffset (if available in parser) to jump directly to the closing tag.
• Eliminate indexOf: Remove text-based searching to prevent "false positive" matches.
• Support Self-Closing Logic: Explicitly handle or skip nodes that don't have a closing pair more gracefully.

Labels
enhancement, Definition, Navigation

[harshanacz]

The Bug Example
Imagine a user has this XML in their editor:

<section>                  <!-- Tag A (Outer) -->
    <section>              <!-- Tag B (Inner) -->
        Some text
    </section>             <!-- Tag C (Inner Close) -->
</section>                 <!-- Tag D (Outer Close) -->

If the user places their cursor on Tag A and presses F12 (Go to Definition) to jump to the matching closing tag, they expect to jump to Tag D.

However, because current xmlDefinition.ts code uses text.indexOf("</section"), it just starts at Tag A and searches blindly forward through the text. It will find the very first it encounters, which is Tag C!

The user jumps to the wrong closing tag, completely breaking the "tag-pair navigation" feature.