From 508a961c1c863aec2a53990edbf77a218062db8e Mon Sep 17 00:00:00 2001
From: Artem Sokolovskii <artem.sokolovskii@qt.io>
Date: Fri, 15 Dec 2023 10:29:09 +0100
Subject: [PATCH] SyntaxHighlighter: Add QTC_USE_THREADED_HIGHLIGHTER env
 variable

QTC_USE_THREADED_HIGHLIGHTER allows to opt-in or out threaded
highlighter. It is on by default.

Change-Id: I3e84f6f80101db5869a45c84cf1e8a8196c02be8
Reviewed-by: hjk <hjk@qt.io>
---
 src/plugins/texteditor/textdocument.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/plugins/texteditor/textdocument.cpp b/src/plugins/texteditor/textdocument.cpp
index 0f19b922048..00138921ef7 100644
--- a/src/plugins/texteditor/textdocument.cpp
+++ b/src/plugins/texteditor/textdocument.cpp
@@ -25,6 +25,7 @@
 
 #include <extensionsystem/pluginmanager.h>
 
+#include <utils/environment.h>
 #include <utils/guard.h>
 #include <utils/mimeutils.h>
 #include <utils/qtcassert.h>
@@ -908,7 +909,9 @@ void TextDocument::resetSyntaxHighlighter(const std::function<SyntaxHighlighter
     if (d->m_highlighterRunner)
         delete d->m_highlighterRunner;
 
-    if (threaded) {
+    static const QString value
+        = qtcEnvironmentVariable("QTC_USE_THREADED_HIGHLIGHTER", "TRUE").toUpper();
+    if (threaded && value == QLatin1String("TRUE")) {
         d->m_highlighterRunner = new ThreadedSyntaxHighlighterRunner(creator, document());
         return;
     }