QTextHtmlImporter: don't forget to appendBlock after block tag closed

If we see a closing tag that really demands a new block after it,
like </ul>, that needs to be done even if some ignorable whitespace
and "inline" tags come after it. Don't get distracted by those.

Also add a comment in QTextDocument::setHtml() to remind the reader that
HTML parsing is a two-pass algorithm.

Fixes: QTBUG-81662
Change-Id: If723c9d3c211a684725055a06bcf87be4e38923a
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>
(cherry picked from commit 60aeeb0e92762d57c208e4212374d30be6490611)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
(cherry picked from commit f0713117d6d0b77c5903ffe9ce3a7d5317021691)

src/gui/text/qtextdocument.cpp

@@ -1267,6 +1267,8 @@ void QTextDocument::setHtml(const QString &html)
     d->enableUndoRedo(false);
     d->beginEditBlock();
     d->clear();
+    // ctor calls parse() to build up QTextHtmlParser::nodes list
+    // then import() populates the QTextDocument from those
     QTextHtmlImporter(this, html, QTextHtmlImporter::ImportToDocument).import();
     d->endEditBlock();
     d->enableUndoRedo(previousState);

src/gui/text/qtextdocumentfragment.cpp

@@ -488,7 +488,8 @@ void QTextHtmlImporter::import()
          *      means there was a tag closing in the input html
          */
         if (currentNodeIdx > 0 && (currentNode->parent != currentNodeIdx - 1)) {
-            blockTagClosed = closeTag();
+            const bool lastBlockTagClosed = closeTag();
+            blockTagClosed = blockTagClosed || lastBlockTagClosed;
             // visually collapse subsequent block tags, but if the element after the closed block tag
             // is for example an inline element (!isBlock) we have to make sure we start a new paragraph by setting
             // hasBlock to false.
@@ -540,6 +541,7 @@ void QTextHtmlImporter::import()
 
             appendBlock(block, currentNode->charFormat);
 
+            blockTagClosed = false;
             hasBlock = true;
         }
 

tests/auto/gui/text/qtextdocumentfragment/tst_qtextdocumentfragment.cpp

@@ -16,6 +16,8 @@
 
 #include <qtextcursor.h>
 
+using namespace Qt::StringLiterals;
+
 QT_FORWARD_DECLARE_CLASS(QTextDocument)
 
 class tst_QTextDocumentFragment : public QObject
@@ -245,6 +247,7 @@ private slots:
     void html_fromFirefox();
     void html_emptyInlineInsideBlock();
     void css_fontAndWordSpacing();
+    void html_brWithWhitespaceAfterList();
 
 private:
     inline void setHtml(const QString &html)
@@ -4320,5 +4323,24 @@ void tst_QTextDocumentFragment::css_fontAndWordSpacing()
     }
 }
 
+void tst_QTextDocumentFragment::html_brWithWhitespaceAfterList() // QTBUG-81662
+{
+    setHtml(QString::fromLatin1("<ul><li>one</li><li>two</li></ul>\n <br/>\nhello"));
+
+    QCOMPARE(doc->blockCount(), 3);
+
+    QTextBlock block = doc->begin();
+    QVERIFY(block.textList());
+
+    block = block.next();
+    QVERIFY(block.textList());
+
+    block = block.next();
+    QCOMPARE(block.text(), u"\u2028hello"_s);
+
+    block = block.next();
+    QVERIFY(block.text().isEmpty());
+}
+
 QTEST_MAIN(tst_QTextDocumentFragment)
 #include "tst_qtextdocumentfragment.moc"