Remove empty block at beginning of imported markdown

An empty QTextDocument already contains a block; so when the formatting
is fully determined, if the document is still empty, then instead of
inserting a new block, we can set formatting on the cursor, which
affects the pre-existing block, before inserting text.  This avoids
leaving a blank line (the default block) above the inserted content.

Fixes: QTBUG-81060
Change-Id: I14e45e300a602493aa59680417d74d4c2b25862d
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

2 files changed, 47 insertions, 3 deletions

diff --git a/src/gui/text/qtextmarkdownimporter.cpp b/src/gui/text/qtextmarkdownimporter.cpp
index 78d18a714b..88965046ce 100644
--- a/src/gui/text/qtextmarkdownimporter.cpp
+++ b/src/gui/text/qtextmarkdownimporter.cpp
@@ -207,7 +207,12 @@ int QTextMarkdownImporter::cbEnterBlock(int blockType, void *det)
         charFmt.setFontWeight(QFont::Bold);
         blockFmt.setHeadingLevel(int(detail->level));
         m_needsInsertBlock = false;
-        m_cursor->insertBlock(blockFmt, charFmt);
+        if (m_doc->isEmpty()) {
+            m_cursor->setBlockFormat(blockFmt);
+            m_cursor->setCharFormat(charFmt);
+        } else {
+            m_cursor->insertBlock(blockFmt, charFmt);
+        }
         qCDebug(lcMD, "H%d", detail->level);
     } break;
     case MD_BLOCK_LI: {
@@ -592,7 +597,12 @@ void QTextMarkdownImporter::insertBlock()
         blockFormat.setMarker(m_markerType);
     if (!m_listStack.isEmpty())
         blockFormat.setIndent(m_listStack.count());
-    m_cursor->insertBlock(blockFormat, charFormat);
+    if (m_doc->isEmpty()) {
+        m_cursor->setBlockFormat(blockFormat);
+        m_cursor->setCharFormat(charFormat);
+    } else {
+        m_cursor->insertBlock(blockFormat, charFormat);
+    }
     if (m_needsInsertList) {
         m_listStack.push(m_cursor->createList(m_listFormat));
     } else if (!m_listStack.isEmpty() && m_listItem) {
diff --git a/tests/auto/gui/text/qtextmarkdownimporter/tst_qtextmarkdownimporter.cpp b/tests/auto/gui/text/qtextmarkdownimporter/tst_qtextmarkdownimporter.cpp
index 2f0b877799..39a1370f6f 100644
--- a/tests/auto/gui/text/qtextmarkdownimporter/tst_qtextmarkdownimporter.cpp
+++ b/tests/auto/gui/text/qtextmarkdownimporter/tst_qtextmarkdownimporter.cpp
@@ -55,12 +55,13 @@ private slots:
     void thematicBreaks();
     void lists_data();
     void lists();
+    void avoidBlankLineAtBeginning_data();
+    void avoidBlankLineAtBeginning();
 };
 
 void tst_QTextMarkdownImporter::headingBulletsContinuations()
 {
     const QStringList expectedBlocks = QStringList() <<
-        "" << // we could do without this blank line before the heading, but currently it happens
         "heading" <<
         "bullet 1 continuation line 1, indented via tab" <<
         "bullet 2 continuation line 2, indented via 4 spaces" <<
@@ -222,5 +223,38 @@ void tst_QTextMarkdownImporter::lists()
     QCOMPARE(doc.toMarkdown(), rewrite);
 }
 
+void tst_QTextMarkdownImporter::avoidBlankLineAtBeginning_data()
+{
+    QTest::addColumn<QString>("input");
+    QTest::addColumn<int>("expectedNumberOfParagraphs");
+
+    QTest::newRow("Text block") << QString("Markdown text") << 1;
+    QTest::newRow("Headline") << QString("Markdown text\n============") << 1;
+    QTest::newRow("Code block") << QString("    Markdown text") << 2;
+    QTest::newRow("Unordered list") << QString("* Markdown text") << 1;
+    QTest::newRow("Ordered list") << QString("1. Markdown text") << 1;
+    QTest::newRow("Blockquote") << QString("> Markdown text") << 1;
+}
+
+void tst_QTextMarkdownImporter::avoidBlankLineAtBeginning() // QTBUG-81060
+{
+    QFETCH(QString, input);
+    QFETCH(int, expectedNumberOfParagraphs);
+
+    QTextDocument doc;
+    QTextMarkdownImporter(QTextMarkdownImporter::DialectGitHub).import(&doc, input);
+    QTextFrame::iterator iterator = doc.rootFrame()->begin();
+    int i = 0;
+    while (!iterator.atEnd()) {
+        QTextBlock block = iterator.currentBlock();
+        // Make sure there is no empty paragraph at the beginning of the document
+        if (i == 0)
+            QVERIFY(!block.text().isEmpty());
+        ++iterator;
+        ++i;
+    }
+    QCOMPARE(i, expectedNumberOfParagraphs);
+}
+
 QTEST_MAIN(tst_QTextMarkdownImporter)
 #include "tst_qtextmarkdownimporter.moc"