QgsColorRampButton::setColorRamp(): fix null pointer dereference

when colorramp argument was nullptr, which could occur when called from QgsColorRampButton::setToNull() The logic to detect if the colorramp was changed was convoluted and wrong too. Spotted by cppcheck
qgis · May 19, 2020 · 996d812 · 996d812
1 parent 146e1e2
commit 996d812
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Showing 2 changed files with 8 additions and 12 deletions.
diff --git a/src/gui/qgscolorrampbutton.cpp b/src/gui/qgscolorrampbutton.cpp
@@ -467,20 +467,17 @@ void QgsColorRampButton::resizeEvent( QResizeEvent *event )
 
 void QgsColorRampButton::setColorRamp( QgsColorRamp *colorramp )
 {
-  QgsColorRamp *oldColorRamp = mColorRamp;
-  mColorRamp = colorramp->clone();
+  if ( colorramp == mColorRamp )
+    return;
+
+  delete mColorRamp;
+  mColorRamp = colorramp ? colorramp->clone() : nullptr;
 
-  // handle when initially set color is same as default (Qt::black); consider it a color change
-  if ( ( oldColorRamp != mColorRamp ) || !mColorRampSet )
+  setButtonBackground();
+  if ( isEnabled() )
   {
-    setButtonBackground();
-    if ( isEnabled() )
-    {
-      emit colorRampChanged();
-    }
+    emit colorRampChanged();
   }
-  delete oldColorRamp;
-  mColorRampSet = true;
 }
 
 void QgsColorRampButton::setColorRampFromName( const QString &name )

diff --git a/src/gui/qgscolorrampbutton.h b/src/gui/qgscolorrampbutton.h
@@ -291,7 +291,6 @@ class GUI_EXPORT QgsColorRampButton : public QToolButton
     QgsColorRamp *mDefaultColorRamp = nullptr;
     QString mContext;
     bool mAcceptLiveUpdates = true;
-    bool mColorRampSet = false;
     bool mShowRandomColorRamp = false;
     bool mShowNull = false;