QSyntaxHighlighter: Delay all highlights until first rehighlight

When calling setDocument (directly or through the constructor) a delayed
rehighlight is initiated. Previously, if any text was changed before
this rehighlight could run it would cancel the rehighlight, even if the
changed text only caused a new block of text to be highlighted.

Fixes: QTBUG-71307
Change-Id: Ib09b664d90906f5b4427105f0e45469806f3a779
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@qt.io>

1 files changed, 15 insertions, 0 deletions

diff --git a/tests/auto/gui/text/qsyntaxhighlighter/tst_qsyntaxhighlighter.cpp b/tests/auto/gui/text/qsyntaxhighlighter/tst_qsyntaxhighlighter.cpp
index 0a2e024701..9d6ce78b24 100644
--- a/tests/auto/gui/text/qsyntaxhighlighter/tst_qsyntaxhighlighter.cpp
+++ b/tests/auto/gui/text/qsyntaxhighlighter/tst_qsyntaxhighlighter.cpp
@@ -74,6 +74,7 @@ private slots:
     void emptyBlocks();
     void setCharFormat();
     void highlightOnInit();
+    void highlightOnInitAndAppend();
     void stopHighlightingWhenStateDoesNotChange();
     void unindent();
     void highlightToEndOfDocument();
@@ -265,6 +266,19 @@ void tst_QSyntaxHighlighter::highlightOnInit()
     QTRY_VERIFY(hl->highlighted);
 }
 
+void tst_QSyntaxHighlighter::highlightOnInitAndAppend()
+{
+    cursor.insertText("Hello");
+    cursor.insertBlock();
+    cursor.insertText("World");
+
+    TestHighlighter *hl = new TestHighlighter(doc);
+    cursor.insertBlock();
+    cursor.insertText("More text");
+    QTRY_VERIFY(hl->highlighted);
+    QVERIFY(hl->highlightedText.endsWith(doc->toPlainText().remove(QLatin1Char('\n'))));
+}
+
 class StateTestHighlighter : public QSyntaxHighlighter
 {
 public:
@@ -330,6 +344,7 @@ void tst_QSyntaxHighlighter::unindent()
     QCOMPARE(doc->toPlainText(), plainText);
 
     TestHighlighter *hl = new TestHighlighter(doc);
+    QTRY_VERIFY(hl->highlighted);
     hl->callCount = 0;
 
     cursor.movePosition(QTextCursor::Start);