From d5e282a85e1c5083c2c8a88ab6cc13d6738737a6 Mon Sep 17 00:00:00 2001
From: Dominic Ricottone <me@dominic-ricottone.com>
Date: Thu, 15 Sep 2022 14:55:39 -0500
Subject: [PATCH] Merging part of Dec 24, 2021 upstream commit

Improves syntax synchronization
---
 syntax/xml.vim | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/syntax/xml.vim b/syntax/xml.vim
index dc3db54..25544ac 100644
--- a/syntax/xml.vim
+++ b/syntax/xml.vim
@@ -11,6 +11,7 @@
 " 20190923 - Fix xmlEndTag to match xmlTag (vim/vim#884)
 " 20190924 - Fix xmlAttribute property (amadeus/vim-xml@d8ce1c946)
 " 20191103 - Enable spell checking globally
+" 20210428 - Improve syntax synchronizing
 
 " CONFIGURATION:
 "   syntax folding can be turned on by
@@ -308,9 +309,12 @@ unlet b:current_syntax
 
 
 " synchronizing
-" TODO !!! to be improved !!!
 
-syn sync match xmlSyncDT grouphere  xmlDocType +\_.\(<!DOCTYPE\)\@=+
+syn sync match xmlSyncComment grouphere xmlComment +<!--+
+syn sync match xmlSyncComment groupthere NONE +-->+
+
+" The following is slow on large documents (and the doctype is optional
+" syn sync match xmlSyncDT grouphere  xmlDocType +\_.\(<!DOCTYPE\)\@=+
 " syn sync match xmlSyncDT groupthere  NONE       +]>+
 
 if exists('g:xml_syntax_folding')
@@ -319,7 +323,7 @@ if exists('g:xml_syntax_folding')
     syn sync match xmlSync groupthere  xmlRegion  +</[^ /!?<>"']\+>+
 endif
 
-syn sync minlines=100
+syn sync minlines=100 maxlines=200
 
 
 " The default highlighting.
@@ -361,4 +365,4 @@ let b:current_syntax = "xml"
 let &cpo = s:xml_cpo_save
 unlet s:xml_cpo_save
 
-" vim: ts=8
+" vim: ts=4
-- 
2.45.2