bug#33887: 26.1; Emacs hangs for several seconds when going to the end of an XML file in nXML mode

[Noam Postavsky]

> There's an issue with the following XML file, which does not have
> any special character, except a single quote in the middle of the
> text.
>
> <root>
> <a>12345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890
> </a>
> </root>
>
> Note that the newline character before the </a> is important.

Right, this is due to chunking by syntax-propertize.  Here's the fix:

0001-Handle-lone-quote-500-characters-away-from-XML-tag-B.patch
Description: patch

Note that you have to be sure to recompile sgml-mode.el AND nxml-mode.el
after applying these patches, 'make' isn't smart enough to do it
automatically (yes, I figured this out the hard way).

>> <t>>1</t>
>>
>> (syntax-ppss) on the location of "1" in the above, gives (-1 ...).  And
>> then (syntax-ppss) on the "/" will give (0 ...).  So the syntax
>> propertize rule for quote use of (zerop (car (syntax-ppss))) no longer
>> works correctly to see whether it's inside or outside a tag.
>>
>> ">" outside of tags should be set to syntax ".", but I would assume that
>> adding a syntax-propertize rule which calls syntax-ppss for every ">"
>> (to check whether it's inside a tag or not) will be very slow, just like
>> calling it for every quote was.

Oh, I figured it out, we can just look at (nth 9 ppss), because the list
of open parens is still okay, regardless of unmatched close parens.

0002-Handle-outside-SGML-XML-tags-Bug-33887.patch
Description: patch