fix: allow sheet closing text in SVS recipes - #377

Thanks for the fix and the clear write-up! The reported case works now, but lastIndexOf still guesses where the sheet ends instead of finding it, so malformed files now get misleading errors:

The root cause is that parseSvs searches the raw text for </sheet> before parsing, and that search is the only scan in the file that is not quote-aware. A fix that addresses it directly is to drop the upfront search and detect the close tag inside the recipe loop:

cursor = openEnd + 1;
while (true) {
  cursor = skipSpace(text, cursor);
  if (cursor >= text.length) fail(sourceName, "SVS_ROOT_UNCLOSED", "Source is missing </sheet>.", source.length);
  if (text.startsWith("</sheet>", cursor)) break;
  // existing recipe parsing, with closingBrace scanning up to text.length
}
const end = cursor + "</sheet>".length;
if (text.slice(end).trim().length > 0) fail(sourceName, "SVS_TRAILING", "Only trivia may follow </sheet>.", end);

The loop only checks for </sheet> between recipes, and closingBrace already skips quoted text, so a quoted </sheet> is read as part of its value. All three inputs above then get the right result. One test for the quoted case is enough.

Would you like to update the PR yourself, or would you prefer that we push the change on top of it?

Pushed your change on top as its own commit, with you as co-author. Your three inputs now behave as you described: the quoted </sheet> with a real close parses, the same value with no real close gives SVS_ROOT_UNCLOSED, and a doubled </sheet> gives SVS_TRAILING, as on main.

I added the second and third to the existing test for the quoted case, and it fails on the lastIndexOf version. Malformed files can now report a different code than on main. For example, a recipe whose } only appears after </sheet> is still rejected, but with SVS_PROPERTY instead of SVS_TRAILING. I also updated the description where it no longer held, the closing tag sentence and the note about the duplicate tag error.

Thanks for updating the PR so quickly and for adding the malformed-file cases to the test! The parser now finds the closing tag from the file structure instead of searching for it, which fixes the root cause. Merged, and it will ship in the next release.