message log viewer: window isn't closeable and last tab has to stay

(fixes #16220)

(cherry picked from commit 2ccdac7)

Author: jef-n

src/gui/qgsmessagelogviewer.cpp

@@ -46,6 +46,15 @@ QgsMessageLogViewer::~QgsMessageLogViewer()
 {
 }
 
+void QgsMessageLogViewer::closeEvent( QCloseEvent *e )
+{
+  e->ignore();
+}
+
+void QgsMessageLogViewer::reject()
+{
+}
+
 void QgsMessageLogViewer::logMessage( QString message, QString tag, QgsMessageLog::MessageLevel level )
 {
   if ( tag.isNull() )
@@ -55,7 +64,7 @@ void QgsMessageLogViewer::logMessage( QString message, QString tag, QgsMessageLo
   for ( i = 0; i < tabWidget->count() && tabWidget->tabText( i ) != tag; i++ )
     ;
 
-  QPlainTextEdit *w;
+  QPlainTextEdit *w = nullptr;
   if ( i < tabWidget->count() )
   {
     w = qobject_cast<QPlainTextEdit *>( tabWidget->widget( i ) );
@@ -67,6 +76,7 @@ void QgsMessageLogViewer::logMessage( QString message, QString tag, QgsMessageLo
     w->setReadOnly( true );
     tabWidget->addTab( w, tag );
     tabWidget->setCurrentIndex( tabWidget->count() - 1 );
+    tabWidget->setTabsClosable( true );
   }
 
   QString prefix = QString( "%1\t%2\t" )
@@ -78,6 +88,6 @@ void QgsMessageLogViewer::logMessage( QString message, QString tag, QgsMessageLo
 
 void QgsMessageLogViewer::closeTab( int index )
 {
-  if ( tabWidget->count() > 1 )
-    tabWidget->removeTab( index );
+  tabWidget->removeTab( index );
+  tabWidget->setTabsClosable( tabWidget->count() > 1 );
 }

src/gui/qgsmessagelogviewer.h

@@ -24,9 +24,7 @@
 #include <QString>
 
 class QStatusBar;
-class QToolButton;
-class QShowEvent;
-class QHideEvent;
+class QCloseEvent;
 
 /** \ingroup gui
  * A generic dialog widget for displaying QGIS log messages.
@@ -41,6 +39,10 @@ class GUI_EXPORT QgsMessageLogViewer: public QDialog, private Ui::QgsMessageLogV
   public slots:
     void logMessage( QString message, QString tag, QgsMessageLog::MessageLevel level );
 
+  protected:
+    void closeEvent( QCloseEvent *e ) override;
+    void reject() override;
+
   private slots:
     void closeTab( int index );
 };