From 31ac9be340e724ab777b2dc487a1a3817ed5b67c Mon Sep 17 00:00:00 2001
From: Denis Rouzaud <denis.rouzaud@gmail.com>
Date: Fri, 13 Nov 2015 08:59:56 +0100
Subject: [PATCH] [search widgets] when selecting _Please select_ find all
 features

---
 .../editorwidgets/core/qgssearchwidgetwrapper.cpp   |  5 +++++
 src/gui/editorwidgets/core/qgssearchwidgetwrapper.h |  3 +++
 .../qgsvaluemapsearchwidgetwrapper.cpp              |  9 ++++++++-
 .../qgsvaluerelationsearchwidgetwrapper.cpp         | 13 ++++++++++---
 4 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/src/gui/editorwidgets/core/qgssearchwidgetwrapper.cpp b/src/gui/editorwidgets/core/qgssearchwidgetwrapper.cpp
index b666956c9df..74965e515ad 100644
--- a/src/gui/editorwidgets/core/qgssearchwidgetwrapper.cpp
+++ b/src/gui/editorwidgets/core/qgssearchwidgetwrapper.cpp
@@ -33,3 +33,8 @@ void QgsSearchWidgetWrapper::setFeature( const QgsFeature& feature )
   Q_UNUSED( feature )
 }
 
+void QgsSearchWidgetWrapper::clearExpression()
+{
+  mExpression = QString( "TRUE" );
+}
+
diff --git a/src/gui/editorwidgets/core/qgssearchwidgetwrapper.h b/src/gui/editorwidgets/core/qgssearchwidgetwrapper.h
index 6fefca63fcc..83d8ca72ef7 100644
--- a/src/gui/editorwidgets/core/qgssearchwidgetwrapper.h
+++ b/src/gui/editorwidgets/core/qgssearchwidgetwrapper.h
@@ -81,6 +81,9 @@ class GUI_EXPORT QgsSearchWidgetWrapper : public QgsWidgetWrapper
     void setFeature( const QgsFeature& feature ) override;
 
   protected:
+    //! clears the expression to search for all features
+    void clearExpression();
+
     QString mExpression;
     int mFieldIdx;
 
diff --git a/src/gui/editorwidgets/qgsvaluemapsearchwidgetwrapper.cpp b/src/gui/editorwidgets/qgsvaluemapsearchwidgetwrapper.cpp
index a23b75f2709..368de908787 100644
--- a/src/gui/editorwidgets/qgsvaluemapsearchwidgetwrapper.cpp
+++ b/src/gui/editorwidgets/qgsvaluemapsearchwidgetwrapper.cpp
@@ -37,7 +37,14 @@ void QgsValueMapSearchWidgetWrapper::comboBoxIndexChanged( int idx )
 {
   if ( mComboBox )
   {
-    setExpression( mComboBox->itemData( idx ).toString() );
+    if ( idx == 0 )
+    {
+      clearExpression();
+    }
+    else
+    {
+      setExpression( mComboBox->itemData( idx ).toString() );
+    }
     emit expressionChanged( mExpression );
   }
 }
diff --git a/src/gui/editorwidgets/qgsvaluerelationsearchwidgetwrapper.cpp b/src/gui/editorwidgets/qgsvaluerelationsearchwidgetwrapper.cpp
index 35221bf7dd9..2c0fb325c62 100644
--- a/src/gui/editorwidgets/qgsvaluerelationsearchwidgetwrapper.cpp
+++ b/src/gui/editorwidgets/qgsvaluerelationsearchwidgetwrapper.cpp
@@ -97,8 +97,15 @@ bool QgsValueRelationSearchWidgetWrapper::valid()
 void QgsValueRelationSearchWidgetWrapper::valueChanged()
 {
   QVariant vl = value();
-  QSettings settings;
-  setExpression( vl.isNull() ? settings.value( "qgis/nullValue", "NULL" ).toString() : vl.toString() );
+  if ( !vl.isValid() )
+  {
+    clearExpression();
+  }
+  else
+  {
+    QSettings settings;
+    setExpression( vl.isNull() ? settings.value( "qgis/nullValue", "NULL" ).toString() : vl.toString() );
+  }
   emit expressionChanged( mExpression );
 }
 
@@ -149,7 +156,7 @@ void QgsValueRelationSearchWidgetWrapper::initWidget( QWidget* editor )
 
   if ( mComboBox )
   {
-    mComboBox->addItem( tr( "Please select" ), QVariant( layer()->fields().at( mFieldIdx ).type() ) );
+    mComboBox->addItem( tr( "Please select" ), QVariant() ); // creates an invalid to allow selecting all features
     if ( config( "AllowNull" ).toBool() )
     {
       mComboBox->addItem( tr( "(no selection)" ), QVariant( layer()->fields().at( mFieldIdx ).type() ) );