Remove context-unaware QgsCoordinateTransform constructors from Python bindings

This forces Python code and plugins to become datum transform aware, and given that upgrading python code is easy (just add QgsProject.instance() as a new argument to the constructor) it's relatively painless to force this on PyQGIS users. Also fix upgrade the easy QgsCoordinateTransform c++ constructors where the project is available, or where using QgsProject::instance() is safe to do. For others, just avoid the deprecated warnings until we can get access to the correct project instance where the transform is being constructed.
2025-04-15 00:04:00 -04:00 · 2017-11-05 21:32:50 +10:00 · 2017-11-05 21:32:50 +10:00 · 86d9492372
commit 86d9492372
parent 91e0afb613
80 changed files with 208 additions and 88 deletions
--- a/doc/api_break.dox
+++ b/doc/api_break.dox
@ -914,11 +914,12 @@ called if changes are made to the CRS database.
 QgsCoordinateTransform        {#qgis_api_break_3_0_QgsCoordinateTransform}
 ----------------------

- QgsCoordinateTransform is no longer a QObject. readXml, writeXml and initialize are all normal public members now,
+- QgsCoordinateTransform is no longer a QObject. Initialize is a normal public members now,
 not slots. The invalidTransformInput() signal has been removed.
 - The extra QgsCoordinateTransform constructors (those not taking QgsCoordinateReferenceSystem arguments) have been
 removed. Now, QgsCoordinateTransform must be created using an already existing source and destination
-QgsCoordinateReferenceSystem object.
+QgsCoordinateReferenceSystem object, and either a QgsCoordinateTransformContext object or a reference to the
+current project instance.
 - QgsCoordinateTransform::clone() has been removed. Just use direct copies instead.
 - sourceCrs() and destCrs() now return a copy instead of a reference to the CRS. This has no effect on PyQGIS code, but c++
 plugins calling these methods will need to be updated.
--- a/python/core/qgscoordinatetransform.sip
+++ b/python/core/qgscoordinatetransform.sip
@ -45,13 +45,6 @@ class QgsCoordinateTransform
 Default constructor, creates an invalid QgsCoordinateTransform.
 %End

-    explicit QgsCoordinateTransform( const QgsCoordinateReferenceSystem &source,
-                                     const QgsCoordinateReferenceSystem &destination );
-%Docstring
- Constructs a QgsCoordinateTransform using QgsCoordinateReferenceSystem objects.
- \param source source CRS, typically of the layer's coordinate system
- \param destination CRS, typically of the map canvas coordinate system
-%End

    explicit QgsCoordinateTransform( const QgsCoordinateReferenceSystem &source,
                                     const QgsCoordinateReferenceSystem &destination,
--- a/python/plugins/MetaSearch/dialogs/maindialog.py
+++ b/python/plugins/MetaSearch/dialogs/maindialog.py
@ -39,7 +39,7 @@ from qgis.PyQt.QtGui import QColor, QCursor

 from qgis.core import (QgsApplication, QgsCoordinateReferenceSystem,
                       QgsCoordinateTransform, QgsGeometry, QgsPointXY,
-                       QgsProviderRegistry, QgsSettings)
+                       QgsProviderRegistry, QgsSettings, QgsProject)
 from qgis.gui import QgsRubberBand
 from qgis.utils import OverrideCursor

@ -400,7 +400,7 @@ class MetaSearchDialog(QDialog, BASE_CLASS):
        if crsid != 4326:  # reproject to EPSG:4326
            src = QgsCoordinateReferenceSystem(crsid)
            dest = QgsCoordinateReferenceSystem(4326)
-            xform = QgsCoordinateTransform(src, dest)
+            xform = QgsCoordinateTransform(src, dest, QgsProject.instance())
            minxy = xform.transform(QgsPointXY(extent.xMinimum(),
                                               extent.yMinimum()))
            maxxy = xform.transform(QgsPointXY(extent.xMaximum(),
@ -570,7 +570,7 @@ class MetaSearchDialog(QDialog, BASE_CLASS):
                dst = self.map.mapSettings().destinationCrs()
                geom = QgsGeometry.fromWkt(points)
                if src.postgisSrid() != dst.postgisSrid():
-                    ctr = QgsCoordinateTransform(src, dst)
+                    ctr = QgsCoordinateTransform(src, dst, QgsProject.instance())
                    try:
                        geom.transform(ctr)
                    except Exception as err:
--- a/python/plugins/processing/algs/qgis/ExportGeometryInfo.py
+++ b/python/plugins/processing/algs/qgis/ExportGeometryInfo.py
@ -126,7 +126,7 @@ class ExportGeometryInfo(QgisAlgorithm):
            self.distance_area.setSourceCrs(source.sourceCrs())
            self.distance_area.setEllipsoid(context.project().ellipsoid())
        elif method == 1:
-            coordTransform = QgsCoordinateTransform(source.sourceCrs(), context.project().crs())
+            coordTransform = QgsCoordinateTransform(source.sourceCrs(), context.project().crs(), context.project())

        features = source.getFeatures()
        total = 100.0 / source.featureCount() if source.featureCount() else 0
--- a/python/plugins/processing/algs/qgis/FindProjection.py
+++ b/python/plugins/processing/algs/qgis/FindProjection.py
@ -34,6 +34,7 @@ from qgis.core import (QgsGeometry,
                       QgsFields,
                       QgsCoordinateReferenceSystem,
                       QgsCoordinateTransform,
+                       QgsCoordinateTransformContext,
                       QgsWkbTypes,
                       QgsProcessingParameterFeatureSource,
                       QgsProcessingParameterExtent,
@ -108,6 +109,7 @@ class FindProjection(QgisAlgorithm):

        found_results = 0

+        transform_context = QgsCoordinateTransformContext()
        for current, srs_id in enumerate(crses_to_check):
            if feedback.isCanceled():
                break
@ -116,7 +118,7 @@ class FindProjection(QgisAlgorithm):
            if not candidate_crs.isValid():
                continue

-            transform_candidate = QgsCoordinateTransform(candidate_crs, target_crs)
+            transform_candidate = QgsCoordinateTransform(candidate_crs, target_crs, transform_context)
            transformed_bounds = QgsGeometry(layer_bounds)
            try:
                if not transformed_bounds.transform(transform_candidate) == 0:
--- a/python/plugins/processing/algs/qgis/SpatialJoinSummary.py
+++ b/python/plugins/processing/algs/qgis/SpatialJoinSummary.py
@ -262,7 +262,7 @@ class SpatialJoinSummary(QgisAlgorithm):
        total = 100.0 / source.featureCount() if source.featureCount() else 0

        # bounding box transform
-        bbox_transform = QgsCoordinateTransform(source.sourceCrs(), join_source.sourceCrs())
+        bbox_transform = QgsCoordinateTransform(source.sourceCrs(), join_source.sourceCrs(), context.project())

        for current, f in enumerate(features):
            if feedback.isCanceled():
--- a/src/analysis/processing/qgsalgorithmtransform.cpp
+++ b/src/analysis/processing/qgsalgorithmtransform.cpp
@ -75,6 +75,7 @@ QgsTransformAlgorithm *QgsTransformAlgorithm::createInstance() const
 bool QgsTransformAlgorithm::prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback * )
 {
  mDestCrs = parameterAsCrs( parameters, QStringLiteral( "TARGET_CRS" ), context );
+  mTransformContext = context.project() ? context.project()->transformContext() : QgsCoordinateTransformContext();
  return true;
 }

@ -84,7 +85,7 @@ QgsFeature QgsTransformAlgorithm::processFeature( const QgsFeature &f, QgsProces
  if ( !mCreatedTransform )
  {
    mCreatedTransform = true;
-    mTransform = QgsCoordinateTransform( sourceCrs(), mDestCrs );
+    mTransform = QgsCoordinateTransform( sourceCrs(), mDestCrs, mTransformContext );
  }

  if ( feature.hasGeometry() )
--- a/src/analysis/processing/qgsalgorithmtransform.h
+++ b/src/analysis/processing/qgsalgorithmtransform.h
@ -56,6 +56,7 @@ class QgsTransformAlgorithm : public QgsProcessingFeatureBasedAlgorithm
    bool mCreatedTransform = false;
    QgsCoordinateReferenceSystem mDestCrs;
    QgsCoordinateTransform mTransform;
+    QgsCoordinateTransformContext mTransformContext;

 };

--- a/src/app/composer/qgscomposermapwidget.cpp
+++ b/src/app/composer/qgscomposermapwidget.cpp
@ -314,7 +314,7 @@ void QgsComposerMapWidget::mapCrsChanged( const QgsCoordinateReferenceSystem &cr
  QgsRectangle newExtent;
  try
  {
-    QgsCoordinateTransform xForm( oldCrs, crs.isValid() ? crs : QgsProject::instance()->crs() );
+    QgsCoordinateTransform xForm( oldCrs, crs.isValid() ? crs : QgsProject::instance()->crs(), QgsProject::instance() );
    QgsRectangle prevExtent = *mComposerMap->currentMapExtent();
    newExtent = xForm.transformBoundingBox( prevExtent );
    updateExtent = true;
@ -513,7 +513,7 @@ void QgsComposerMapWidget::mSetToMapCanvasExtentButton_clicked()
    try
    {
      QgsCoordinateTransform xForm( QgisApp::instance()->mapCanvas()->mapSettings().destinationCrs(),
-                                    mComposerMap->crs() );
+                                    mComposerMap->crs(), QgsProject::instance() );
      newExtent = xForm.transformBoundingBox( newExtent );
    }
    catch ( QgsCsException & )
@ -546,7 +546,7 @@ void QgsComposerMapWidget::mViewExtentInCanvasButton_clicked()
      try
      {
        QgsCoordinateTransform xForm( mComposerMap->crs(),
-                                      QgisApp::instance()->mapCanvas()->mapSettings().destinationCrs() );
+                                      QgisApp::instance()->mapCanvas()->mapSettings().destinationCrs(), QgsProject::instance() );
        currentMapExtent = xForm.transformBoundingBox( currentMapExtent );
      }
      catch ( QgsCsException & )
--- a/src/app/gps/qgsgpsinformationwidget.cpp
+++ b/src/app/gps/qgsgpsinformationwidget.cpp
@ -684,7 +684,7 @@ void QgsGPSInformationWidget::displayGPSInformation( const QgsGPSInformation &in
    if ( radRecenterMap->isChecked() || radRecenterWhenNeeded->isChecked() )
    {
      QgsCoordinateReferenceSystem mypSRS = mpCanvas->mapSettings().destinationCrs();
-      QgsCoordinateTransform myTransform( mWgs84CRS, mypSRS ); // use existing WGS84 CRS
+      QgsCoordinateTransform myTransform( mWgs84CRS, mypSRS, QgsProject::instance() ); // use existing WGS84 CRS

      QgsPointXY myPoint = myTransform.transform( myNewCenter );
      //keep the extent the same just center the map canvas in the display so our feature is in the middle
@ -758,7 +758,7 @@ void QgsGPSInformationWidget::addVertex()
  QgsPointXY myPoint;
  if ( mpCanvas )
  {
-    QgsCoordinateTransform t( mWgs84CRS, mpCanvas->mapSettings().destinationCrs() );
+    QgsCoordinateTransform t( mWgs84CRS, mpCanvas->mapSettings().destinationCrs(), QgsProject::instance() );
    myPoint = t.transform( mLastGpsPosition );
  }
  else
@ -809,7 +809,7 @@ void QgsGPSInformationWidget::mBtnCloseFeature_clicked()
  {
    QgsFeature *f = new QgsFeature( 0 );

-    QgsCoordinateTransform t( mWgs84CRS, vlayer->crs() );
+    QgsCoordinateTransform t( mWgs84CRS, vlayer->crs(), QgsProject::instance() );
    QgsPointXY myPoint = t.transform( mLastGpsPosition );
    double x = myPoint.x();
    double y = myPoint.y();
@ -864,7 +864,7 @@ void QgsGPSInformationWidget::mBtnCloseFeature_clicked()
      {
        QgsPointXY savePoint = *it;
        // transform the gps point into the layer crs
-        QgsCoordinateTransform t( mWgs84CRS, vlayer->crs() );
+        QgsCoordinateTransform t( mWgs84CRS, vlayer->crs(), QgsProject::instance() );
        QgsPointXY myPoint = t.transform( savePoint );

        wkbPtr << myPoint.x() << myPoint.y();
@ -887,7 +887,7 @@ void QgsGPSInformationWidget::mBtnCloseFeature_clicked()
      {
        QgsPointXY savePoint = *it;
        // transform the gps point into the layer crs
-        QgsCoordinateTransform t( mWgs84CRS, vlayer->crs() );
+        QgsCoordinateTransform t( mWgs84CRS, vlayer->crs(), QgsProject::instance() );
        QgsPointXY myPoint = t.transform( savePoint );
        wkbPtr << myPoint.x() << myPoint.y();
      }
--- a/src/app/gps/qgsgpsmarker.cpp
+++ b/src/app/gps/qgsgpsmarker.cpp
@ -19,6 +19,7 @@
 #include "qgscoordinatetransform.h"
 #include "qgsmapcanvas.h"
 #include "qgsexception.h"
+#include "qgsproject.h"

 QgsGpsMarker::QgsGpsMarker( QgsMapCanvas *mapCanvas )
  : QgsMapCanvasItem( mapCanvas )
@ -42,7 +43,7 @@ void QgsGpsMarker::setCenter( const QgsPointXY &point )
  //transform to map crs
  if ( mMapCanvas )
  {
-    QgsCoordinateTransform t( mWgs84CRS, mMapCanvas->mapSettings().destinationCrs() );
+    QgsCoordinateTransform t( mWgs84CRS, mMapCanvas->mapSettings().destinationCrs(), QgsProject::instance() );
    try
    {
      mCenter = t.transform( point );
--- a/src/app/nodetool/qgsnodeeditor.cpp
+++ b/src/app/nodetool/qgsnodeeditor.cpp
@ -22,6 +22,7 @@
 #include "qgsvertexentry.h"
 #include "qgsvectorlayer.h"
 #include "qgsgeometryutils.h"
+#include "qgsproject.h"

 #include <QTableWidget>
 #include <QHeaderView>
@ -366,7 +367,7 @@ void QgsNodeEditor::zoomToNode( int idx )
  double y = mSelectedFeature->vertexMap().at( idx )->point().y();
  QgsPointXY newCenter( x, y );

-  QgsCoordinateTransform t( mLayer->crs(), mCanvas->mapSettings().destinationCrs() );
+  QgsCoordinateTransform t( mLayer->crs(), mCanvas->mapSettings().destinationCrs(), QgsProject::instance() );
  QgsPointXY tCenter = t.transform( newCenter );

  QPolygonF ext = mCanvas->mapSettings().visiblePolygon();
--- a/src/app/qgisapp.cpp
+++ b/src/app/qgisapp.cpp
@ -5759,7 +5759,7 @@ void QgisApp::dxfExport()
      //extent
      if ( d.exportMapExtent() )
      {
-        QgsCoordinateTransform t( mapCanvas()->mapSettings().destinationCrs(), d.crs() );
+        QgsCoordinateTransform t( mapCanvas()->mapSettings().destinationCrs(), d.crs(), QgsProject::instance() );
        dxfExport.setExtent( t.transformBoundingBox( mapCanvas()->extent() ) );
      }
    }
@ -7019,7 +7019,7 @@ void QgisApp::saveAsVectorFileGeneral( QgsVectorLayer *vlayer, bool symbologyOpt

    if ( destCRS.isValid() && destCRS != vlayer->crs() )
    {
-      ct = QgsCoordinateTransform( vlayer->crs(), destCRS );
+      ct = QgsCoordinateTransform( vlayer->crs(), destCRS, QgsProject::instance() );

      //ask user about datum transformation
      QgsSettings settings;
@ -9493,7 +9493,7 @@ void QgisApp::legendLayerZoomNative()
    QSize s = mMapCanvas->mapSettings().outputSize();
    QgsPointXY p1( e.center().x(), e.center().y() );
    QgsPointXY p2( e.center().x() + e.width() / s.width(), e.center().y() + e.height() / s.height() );
-    QgsCoordinateTransform ct( mMapCanvas->mapSettings().destinationCrs(), layer->crs() );
+    QgsCoordinateTransform ct( mMapCanvas->mapSettings().destinationCrs(), layer->crs(), QgsProject::instance() );
    p1 = ct.transform( p1 );
    p2 = ct.transform( p2 );
    double width = std::sqrt( p1.sqrDist( p2 ) ); // width (actually the diagonal) of reprojected pixel
--- a/src/app/qgsbookmarks.cpp
+++ b/src/app/qgsbookmarks.cpp
@ -253,7 +253,7 @@ void QgsBookmarks::zoomToBookmark()
       authid != QgisApp::instance()->mapCanvas()->mapSettings().destinationCrs().authid() )
  {
    QgsCoordinateTransform ct( QgsCoordinateReferenceSystem::fromOgcWmsCrs( authid ),
-                               QgisApp::instance()->mapCanvas()->mapSettings().destinationCrs() );
+                               QgisApp::instance()->mapCanvas()->mapSettings().destinationCrs(), QgsProject::instance() );
    rect = ct.transform( rect );
    if ( rect.isEmpty() )
    {
--- a/src/app/qgsclipboard.cpp
+++ b/src/app/qgsclipboard.cpp
@ -38,6 +38,7 @@
 #include "qgssettings.h"
 #include "qgisapp.h"
 #include "qgsmapcanvas.h"
+#include "qgsproject.h"

 QgsClipboard::QgsClipboard()
 {
@ -277,7 +278,7 @@ QgsFeatureList QgsClipboard::transformedCopyOf( const QgsCoordinateReferenceSyst
  }
  else
  {
-    ct = QgsCoordinateTransform( crs(), destCRS );
+    ct = QgsCoordinateTransform( crs(), destCRS, QgsProject::instance() );
  }

  QgsDebugMsg( "transforming clipboard." );
--- a/src/app/qgsdecorationlayoutextent.cpp
+++ b/src/app/qgsdecorationlayoutextent.cpp
@ -139,7 +139,7 @@ void QgsDecorationLayoutExtent::render( const QgsMapSettings &mapSettings, QgsRe
      {
        // reproject extent
        QgsCoordinateTransform ct( map->crs(),
-                                   mapSettings.destinationCrs() );
+                                   mapSettings.destinationCrs(), QgsProject::instance() );
        g = g.densifyByCount( 20 );
        try
        {
--- a/src/app/qgsmapcanvasdockwidget.cpp
+++ b/src/app/qgsmapcanvasdockwidget.cpp
@ -322,7 +322,7 @@ void QgsMapCanvasDockWidget::syncViewCenter( QgsMapCanvas *sourceCanvas )

  // reproject extent
  QgsCoordinateTransform ct( sourceCanvas->mapSettings().destinationCrs(),
-                             destCanvas->mapSettings().destinationCrs() );
+                             destCanvas->mapSettings().destinationCrs(), QgsProject::instance() );
  try
  {
    destCanvas->setCenter( ct.transform( sourceCanvas->center() ) );
@ -412,7 +412,7 @@ void QgsMapCanvasDockWidget::syncMarker( const QgsPointXY &p )

  // reproject point
  QgsCoordinateTransform ct( mMainCanvas->mapSettings().destinationCrs(),
-                             mMapCanvas->mapSettings().destinationCrs() );
+                             mMapCanvas->mapSettings().destinationCrs(), QgsProject::instance() );
  QgsPointXY t = p;
  try
  {
@ -450,7 +450,7 @@ void QgsMapCanvasDockWidget::updateExtentRect()
  {
    // reproject extent
    QgsCoordinateTransform ct( mMainCanvas->mapSettings().destinationCrs(),
-                               mMapCanvas->mapSettings().destinationCrs() );
+                               mMapCanvas->mapSettings().destinationCrs(), QgsProject::instance() );
    g = g.densifyByCount( 5 );
    try
    {
--- a/src/app/qgsmaptoolannotation.cpp
+++ b/src/app/qgsmaptoolannotation.cpp
@ -359,7 +359,7 @@ QgsPointXY QgsMapToolAnnotation::transformCanvasToAnnotation( QgsPointXY p, QgsA
 {
  if ( annotation->mapPositionCrs() != mCanvas->mapSettings().destinationCrs() )
  {
-    QgsCoordinateTransform transform( mCanvas->mapSettings().destinationCrs(), annotation->mapPositionCrs() );
+    QgsCoordinateTransform transform( mCanvas->mapSettings().destinationCrs(), annotation->mapPositionCrs(), QgsProject::instance() );
    try
    {
      p = transform.transform( p );
--- a/src/app/qgsmaptoolselectutils.cpp
+++ b/src/app/qgsmaptoolselectutils.cpp
@ -28,6 +28,7 @@ email                : jpalmer at linz dot govt dot nz
 #include "qgsexception.h"
 #include "qgslogger.h"
 #include "qgis.h"
+#include "qgsproject.h"

 #include <QMouseEvent>
 #include <QApplication>
@ -176,7 +177,7 @@ QgsFeatureIds QgsMapToolSelectUtils::getMatchingFeatures( QgsMapCanvas *canvas,

  try
  {
-    QgsCoordinateTransform ct( canvas->mapSettings().destinationCrs(), vlayer->crs() );
+    QgsCoordinateTransform ct( canvas->mapSettings().destinationCrs(), vlayer->crs(), QgsProject::instance() );

    if ( !ct.isShortCircuited() && selectGeomTrans.type() == QgsWkbTypes::PolygonGeometry )
    {
--- a/src/app/qgsmaptoolshowhidelabels.cpp
+++ b/src/app/qgsmaptoolshowhidelabels.cpp
@ -199,7 +199,7 @@ bool QgsMapToolShowHideLabels::selectedFeatures( QgsVectorLayer *vlayer,

  try
  {
-    QgsCoordinateTransform ct( mCanvas->mapSettings().destinationCrs(), vlayer->crs() );
+    QgsCoordinateTransform ct( mCanvas->mapSettings().destinationCrs(), vlayer->crs(), QgsProject::instance() );
    selectGeomTrans.transform( ct );
  }
  catch ( QgsCsException &cse )
--- a/src/app/qgsmeasuretool.cpp
+++ b/src/app/qgsmeasuretool.cpp
@ -26,6 +26,7 @@
 #include "qgsmeasuretool.h"
 #include "qgsmessagelog.h"
 #include "qgssettings.h"
+#include "qgsproject.h"

 #include <QMessageBox>
 #include <QMouseEvent>
@ -133,7 +134,7 @@ void QgsMeasureTool::updateSettings()

    mDialog->restart();
    mDone = lastDone;
-    QgsCoordinateTransform ct( mDestinationCrs, mCanvas->mapSettings().destinationCrs() );
+    QgsCoordinateTransform ct( mDestinationCrs, mCanvas->mapSettings().destinationCrs(), QgsProject::instance() );

    Q_FOREACH ( const QgsPointXY &previousPoint, points )
    {
--- a/src/app/qgsprojectproperties.cpp
+++ b/src/app/qgsprojectproperties.cpp
@ -163,7 +163,7 @@ QgsProjectProperties::QgsProjectProperties( QgsMapCanvas *mapCanvas, QWidget *pa
  {
    // reproject extent
    QgsCoordinateTransform ct( QgsProject::instance()->crs(),
-                               QgsCoordinateReferenceSystem::fromEpsgId( 4326 ) );
+                               QgsCoordinateReferenceSystem::fromEpsgId( 4326 ), QgsProject::instance() );

    g = g.densifyByCount( 5 );
    try
--- a/src/core/composer/qgscomposerattributetablev2.cpp
+++ b/src/core/composer/qgscomposerattributetablev2.cpp
@ -413,7 +413,7 @@ bool QgsComposerAttributeTableV2::getTableContents( QgsComposerTableContents &co
    if ( layer )
    {
      //transform back to layer CRS
-      QgsCoordinateTransform coordTransform( layer->crs(), mComposerMap->crs() );
+      QgsCoordinateTransform coordTransform( layer->crs(), mComposerMap->crs(), mComposition->project() );
      try
      {
        selectionRect = coordTransform.transformBoundingBox( selectionRect, QgsCoordinateTransform::ReverseTransform );
--- a/src/core/composer/qgscomposermap.cpp
+++ b/src/core/composer/qgscomposermap.cpp
@ -1890,7 +1890,7 @@ QPointF QgsComposerMap::composerMapPosForItem( const QgsAnnotation *annotation )
  if ( annotationCrs != crs() )
  {
    //need to reproject
-    QgsCoordinateTransform t( annotationCrs, crs() );
+    QgsCoordinateTransform t( annotationCrs, crs(), mComposition->project() );
    double z = 0.0;
    t.transformInPlace( mapX, mapY, z );
  }
--- a/src/core/composer/qgscomposermapgrid.cpp
+++ b/src/core/composer/qgscomposermapgrid.cpp
@ -2349,7 +2349,7 @@ int QgsComposerMapGrid::crsGridParams( QgsRectangle &crsRect, QgsCoordinateTrans

  try
  {
-    QgsCoordinateTransform tr( mComposerMap->crs(), mCRS );
+    QgsCoordinateTransform tr( mComposerMap->crs(), mCRS, mComposerMap->composition()->project() );
    QPolygonF mapPolygon = mComposerMap->transformedMapPolygon();
    QRectF mbr = mapPolygon.boundingRect();
    QgsRectangle mapBoundingRect( mbr.left(), mbr.bottom(), mbr.right(), mbr.top() );
--- a/src/core/composer/qgscomposermapoverview.cpp
+++ b/src/core/composer/qgscomposermapoverview.cpp
@ -82,7 +82,7 @@ void QgsComposerMapOverview::draw( QPainter *painter )

    // reproject extent
    QgsCoordinateTransform ct( overviewFrameMap->crs(),
-                               mComposerMap->crs() );
+                               mComposerMap->crs(), mComposition->project() );
    g = g.densifyByCount( 20 );
    try
    {
--- a/src/core/expression/qgsexpressionfunction.cpp
+++ b/src/core/expression/qgsexpressionfunction.cpp
@ -3369,7 +3369,9 @@ static QVariant fcnTransformGeometry( const QVariantList &values, const QgsExpre
  if ( ! d.isValid() )
    return QVariant::fromValue( fGeom );

+  Q_NOWARN_DEPRECATED_PUSH
  QgsCoordinateTransform t( s, d );
+  Q_NOWARN_DEPRECATED_POP
  try
  {
    if ( fGeom.transform( t ) == 0 )
--- a/src/core/processing/qgsprocessingparameters.cpp
+++ b/src/core/processing/qgsprocessingparameters.cpp
@ -504,7 +504,7 @@ QgsRectangle QgsProcessingParameters::parameterAsExtent( const QgsProcessingPara
    QgsReferencedRectangle rr = val.value<QgsReferencedRectangle>();
    if ( crs.isValid() && rr.crs().isValid() && crs != rr.crs() )
    {
-      QgsCoordinateTransform ct( rr.crs(), crs );
+      QgsCoordinateTransform ct( rr.crs(), crs, context.project() );
      try
      {
        return ct.transformBoundingBox( rr );
@ -544,7 +544,7 @@ QgsRectangle QgsProcessingParameters::parameterAsExtent( const QgsProcessingPara
      QgsCoordinateReferenceSystem rectCrs( match.captured( 5 ) );
      if ( crs.isValid() && rectCrs.isValid() && crs != rectCrs )
      {
-        QgsCoordinateTransform ct( rectCrs, crs );
+        QgsCoordinateTransform ct( rectCrs, crs, context.project() );
        try
        {
          return ct.transformBoundingBox( rect );
@ -564,7 +564,7 @@ QgsRectangle QgsProcessingParameters::parameterAsExtent( const QgsProcessingPara
    QgsRectangle rect = layer->extent();
    if ( crs.isValid() && layer->crs().isValid() && crs != layer->crs() )
    {
-      QgsCoordinateTransform ct( layer->crs(), crs );
+      QgsCoordinateTransform ct( layer->crs(), crs, context.project() );
      try
      {
        return ct.transformBoundingBox( rect );
@ -593,7 +593,7 @@ QgsGeometry QgsProcessingParameters::parameterAsExtentGeometry( const QgsProcess
    if ( crs.isValid() && rr.crs().isValid() && crs != rr.crs() )
    {
      g = g.densifyByCount( 20 );
-      QgsCoordinateTransform ct( rr.crs(), crs );
+      QgsCoordinateTransform ct( rr.crs(), crs, context.project() );
      try
      {
        g.transform( ct );
@ -634,7 +634,7 @@ QgsGeometry QgsProcessingParameters::parameterAsExtentGeometry( const QgsProcess
        if ( crs.isValid() && rectCrs.isValid() && crs != rectCrs )
        {
          g = g.densifyByCount( 20 );
-          QgsCoordinateTransform ct( rectCrs, crs );
+          QgsCoordinateTransform ct( rectCrs, crs, context.project() );
          try
          {
            g.transform( ct );
@ -657,7 +657,7 @@ QgsGeometry QgsProcessingParameters::parameterAsExtentGeometry( const QgsProcess
    if ( crs.isValid() && layer->crs().isValid() && crs != layer->crs() )
    {
      g = g.densifyByCount( 20 );
-      QgsCoordinateTransform ct( layer->crs(), crs );
+      QgsCoordinateTransform ct( layer->crs(), crs, context.project() );
      try
      {
        g.transform( ct );
@ -724,7 +724,7 @@ QgsPointXY QgsProcessingParameters::parameterAsPoint( const QgsProcessingParamet
    QgsReferencedPointXY rp = val.value<QgsReferencedPointXY>();
    if ( crs.isValid() && rp.crs().isValid() && crs != rp.crs() )
    {
-      QgsCoordinateTransform ct( rp.crs(), crs );
+      QgsCoordinateTransform ct( rp.crs(), crs, context.project() );
      try
      {
        return ct.transform( rp );
@ -762,7 +762,7 @@ QgsPointXY QgsProcessingParameters::parameterAsPoint( const QgsProcessingParamet
      QgsCoordinateReferenceSystem pointCrs( match.captured( 3 ) );
      if ( crs.isValid() && pointCrs.isValid() && crs != pointCrs )
      {
-        QgsCoordinateTransform ct( pointCrs, crs );
+        QgsCoordinateTransform ct( pointCrs, crs, context.project() );
        try
        {
          return ct.transform( pt );
--- a/src/core/processing/qgsprocessingutils.cpp
+++ b/src/core/processing/qgsprocessingutils.cpp
@ -458,7 +458,9 @@ QgsRectangle QgsProcessingUtils::combineLayerExtents( const QList<QgsMapLayer *>
    if ( crs.isValid() )
    {
      //transform layer extent to target CRS
+      Q_NOWARN_DEPRECATED_PUSH
      QgsCoordinateTransform ct( layer->crs(), crs );
+      Q_NOWARN_DEPRECATED_POP
      try
      {
        QgsRectangle reprojExtent = ct.transformBoundingBox( layer->extent() );
--- a/src/core/providers/memory/qgsmemoryfeatureiterator.cpp
+++ b/src/core/providers/memory/qgsmemoryfeatureiterator.cpp
@ -30,7 +30,9 @@ QgsMemoryFeatureIterator::QgsMemoryFeatureIterator( QgsMemoryFeatureSource *sour
 {
  if ( mRequest.destinationCrs().isValid() && mRequest.destinationCrs() != mSource->mCrs )
  {
+    Q_NOWARN_DEPRECATED_PUSH
    mTransform = QgsCoordinateTransform( mSource->mCrs, mRequest.destinationCrs() );
+    Q_NOWARN_DEPRECATED_POP
  }
  try
  {
--- a/src/core/qgsbearingutils.cpp
+++ b/src/core/qgsbearingutils.cpp
@ -24,7 +24,9 @@
 double QgsBearingUtils::bearingTrueNorth( const QgsCoordinateReferenceSystem &crs, const QgsPointXY &point )
 {
  // step 1 - transform point into WGS84 geographic crs
+  Q_NOWARN_DEPRECATED_PUSH
  QgsCoordinateTransform transform( crs, QgsCoordinateReferenceSystem::fromEpsgId( 4326 ) );
+  Q_NOWARN_DEPRECATED_POP

  if ( !transform.isValid() )
  {
--- a/src/core/qgscachedfeatureiterator.cpp
+++ b/src/core/qgscachedfeatureiterator.cpp
@ -23,7 +23,9 @@ QgsCachedFeatureIterator::QgsCachedFeatureIterator( QgsVectorLayerCache *vlCache
 {
  if ( mRequest.destinationCrs().isValid() && mRequest.destinationCrs() != mVectorLayerCache->sourceCrs() )
  {
+    Q_NOWARN_DEPRECATED_PUSH
    mTransform = QgsCoordinateTransform( mVectorLayerCache->sourceCrs(), mRequest.destinationCrs() );
+    Q_NOWARN_DEPRECATED_POP
  }
  try
  {
@ -109,7 +111,9 @@ QgsCachedFeatureWriterIterator::QgsCachedFeatureWriterIterator( QgsVectorLayerCa
 {
  if ( mRequest.destinationCrs().isValid() && mRequest.destinationCrs() != mVectorLayerCache->sourceCrs() )
  {
+    Q_NOWARN_DEPRECATED_PUSH
    mTransform = QgsCoordinateTransform( mVectorLayerCache->sourceCrs(), mRequest.destinationCrs() );
+    Q_NOWARN_DEPRECATED_POP
  }
  try
  {
--- a/src/core/qgscoordinatetransform.h
+++ b/src/core/qgscoordinatetransform.h
@ -64,9 +64,14 @@ class CORE_EXPORT QgsCoordinateTransform
     * Constructs a QgsCoordinateTransform using QgsCoordinateReferenceSystem objects.
     * \param source source CRS, typically of the layer's coordinate system
     * \param destination CRS, typically of the map canvas coordinate system
+     * \warning Use of this constructor is strongly discouraged, as it will not
+     * correctly handle the user's datum transform setup. Instead the constructor
+     * variant which accepts a QgsCoordinateTransformContext or QgsProject
+     * argument should be used instead. It is highly likely that this constructor
+     * will be removed in future QGIS versions.
+     * \note Not available in Python bindings.
     */
-    explicit QgsCoordinateTransform( const QgsCoordinateReferenceSystem &source,
-                                     const QgsCoordinateReferenceSystem &destination );
+    Q_DECL_DEPRECATED explicit QgsCoordinateTransform( const QgsCoordinateReferenceSystem &source, const QgsCoordinateReferenceSystem &destination ) SIP_SKIP;

    /**
     * Constructs a QgsCoordinateTransform to transform from the \a source
--- a/src/core/qgscoordinateutils.cpp
+++ b/src/core/qgscoordinateutils.cpp
@ -73,7 +73,9 @@ QString QgsCoordinateUtils::formatCoordinateForProject( const QgsPointXY &point,
    if ( destCrs.isValid() && !destCrs.isGeographic() )
    {
      // need to transform to geographic coordinates
+      Q_NOWARN_DEPRECATED_PUSH
      QgsCoordinateTransform ct( destCrs, QgsCoordinateReferenceSystem( GEOSRID ) );
+      Q_NOWARN_DEPRECATED_POP
      try
      {
        geo = ct.transform( point );
--- a/src/core/qgscrscache.cpp
+++ b/src/core/qgscrscache.cpp
@ -44,7 +44,9 @@ QgsCoordinateTransform QgsCoordinateTransformCache::transform( const QString &sr
  //not found, insert new value
  QgsCoordinateReferenceSystem srcCrs = QgsCoordinateReferenceSystem::fromOgcWmsCrs( srcAuthId );
  QgsCoordinateReferenceSystem destCrs = QgsCoordinateReferenceSystem::fromOgcWmsCrs( destAuthId );
+  Q_NOWARN_DEPRECATED_PUSH
  QgsCoordinateTransform ct = QgsCoordinateTransform( srcCrs, destCrs );
+  Q_NOWARN_DEPRECATED_POP
  ct.setSourceDatumTransform( srcDatumTransform );
  ct.setDestinationDatumTransform( destDatumTransform );
  ct.initialize();
--- a/src/core/qgspointlocator.cpp
+++ b/src/core/qgspointlocator.cpp
@ -626,7 +626,9 @@ QgsPointLocator::QgsPointLocator( QgsVectorLayer *layer, const QgsCoordinateRefe
 {
  if ( destCRS.isValid() )
  {
+    Q_NOWARN_DEPRECATED_PUSH
    mTransform = QgsCoordinateTransform( layer->crs(), destCRS );
+    Q_NOWARN_DEPRECATED_POP
  }

  setExtent( extent );
--- a/src/core/qgstracer.cpp
+++ b/src/core/qgstracer.cpp
@ -475,7 +475,9 @@ bool QgsTracer::initGraph()
  int featuresCounted = 0;
  Q_FOREACH ( QgsVectorLayer *vl, mLayers )
  {
+    Q_NOWARN_DEPRECATED_PUSH
    QgsCoordinateTransform ct( vl->crs(), mCRS );
+    Q_NOWARN_DEPRECATED_POP

    QgsFeatureRequest request;
    request.setSubsetOfAttributes( QgsAttributeList() );
--- a/src/core/qgsvectorfilewriter.cpp
+++ b/src/core/qgsvectorfilewriter.cpp
@ -2294,7 +2294,9 @@ QgsVectorFileWriter::writeAsVectorFormat( QgsVectorLayer *layer,
  QgsCoordinateTransform ct;
  if ( destCRS.isValid() && layer )
  {
+    Q_NOWARN_DEPRECATED_PUSH
    ct = QgsCoordinateTransform( layer->crs(), destCRS );
+    Q_NOWARN_DEPRECATED_POP
  }

  QgsVectorFileWriter::WriterError error = writeAsVectorFormat( layer, fileName, fileEncoding, ct, driverName, onlySelected,
--- a/src/core/qgsvectorlayerdiagramprovider.cpp
+++ b/src/core/qgsvectorlayerdiagramprovider.cpp
@ -145,8 +145,12 @@ bool QgsVectorLayerDiagramProvider::prepare( const QgsRenderContext &context, QS
    // this is context for layer rendering - use its CT as it includes correct datum transform
    s2.setCoordinateTransform( context.coordinateTransform() );
  else
+  {
    // otherwise fall back to creating our own CT - this one may not have the correct datum transform!
+    Q_NOWARN_DEPRECATED_PUSH
    s2.setCoordinateTransform( QgsCoordinateTransform( mLayerCrs, mapSettings.destinationCrs() ) );
+    Q_NOWARN_DEPRECATED_POP
+  }

  s2.setRenderer( mDiagRenderer );

--- a/src/core/qgsvectorlayerexporter.cpp
+++ b/src/core/qgsvectorlayerexporter.cpp
@ -332,7 +332,11 @@ QgsVectorLayerExporter::exportLayer( QgsVectorLayer *layer,

  // Create our transform
  if ( destCRS.isValid() )
+  {
+    Q_NOWARN_DEPRECATED_PUSH
    ct = QgsCoordinateTransform( layer->crs(), destCRS );
+    Q_NOWARN_DEPRECATED_POP
+  }

  // Check for failure
  if ( !ct.isValid() )
--- a/src/core/qgsvectorlayerfeatureiterator.cpp
+++ b/src/core/qgsvectorlayerfeatureiterator.cpp
@ -115,7 +115,9 @@ QgsVectorLayerFeatureIterator::QgsVectorLayerFeatureIterator( QgsVectorLayerFeat
 {
  if ( mRequest.destinationCrs().isValid() && mRequest.destinationCrs() != mSource->mCrs )
  {
+    Q_NOWARN_DEPRECATED_PUSH
    mTransform = QgsCoordinateTransform( mSource->mCrs, mRequest.destinationCrs() );
+    Q_NOWARN_DEPRECATED_POP
  }
  try
  {
--- a/src/core/qgsvectorlayerlabelprovider.cpp
+++ b/src/core/qgsvectorlayerlabelprovider.cpp
@ -176,8 +176,12 @@ bool QgsVectorLayerLabelProvider::prepare( const QgsRenderContext &context, QSet
    // this is context for layer rendering - use its CT as it includes correct datum transform
    lyr.ct = context.coordinateTransform();
  else
+  {
+    Q_NOWARN_DEPRECATED_PUSH
    // otherwise fall back to creating our own CT - this one may not have the correct datum transform!
    lyr.ct = QgsCoordinateTransform( mCrs, mapSettings.destinationCrs() );
+    Q_NOWARN_DEPRECATED_POP
+  }
  lyr.ptZero = lyr.xform->toMapCoordinates( 0, 0 );
  lyr.ptOne = lyr.xform->toMapCoordinates( 1, 0 );

--- a/src/core/raster/qgsrasterfilewriter.cpp
+++ b/src/core/raster/qgsrasterfilewriter.cpp
@ -226,7 +226,9 @@ QgsRasterFileWriter::WriterError QgsRasterFileWriter::writeDataRaster( const Qgs
      QgsRasterProjector *projector = pipe->projector();
      if ( projector && projector->destinationCrs() != projector->sourceCrs() )
      {
+        Q_NOWARN_DEPRECATED_PUSH
        QgsCoordinateTransform ct( projector->destinationCrs(), projector->sourceCrs() );
+        Q_NOWARN_DEPRECATED_POP
        srcExtent = ct.transformBoundingBox( outputExtent );
      }
      if ( !srcProvider->extent().contains( srcExtent ) )
--- a/src/gui/qgsextentgroupbox.cpp
+++ b/src/gui/qgsextentgroupbox.cpp
@ -101,7 +101,7 @@ void QgsExtentGroupBox::setOutputCrs( const QgsCoordinateReferenceSystem &output
      case UserExtent:
        try
        {
-          QgsCoordinateTransform ct( mOutputCrs, outputCrs );
+          QgsCoordinateTransform ct( mOutputCrs, outputCrs, QgsProject::instance() );
          QgsRectangle extent = ct.transformBoundingBox( outputExtent() );
          mOutputCrs = outputCrs;
          setOutputExtentFromUser( extent, outputCrs );
@ -129,7 +129,7 @@ void QgsExtentGroupBox::setOutputExtent( const QgsRectangle &r, const QgsCoordin
  {
    try
    {
-      QgsCoordinateTransform ct( srcCrs, mOutputCrs );
+      QgsCoordinateTransform ct( srcCrs, mOutputCrs, QgsProject::instance() );
      extent = ct.transformBoundingBox( r );
    }
    catch ( QgsCsException & )
--- a/src/gui/qgsmapcanvas.cpp
+++ b/src/gui/qgsmapcanvas.cpp
@ -354,7 +354,7 @@ void QgsMapCanvas::setDestinationCrs( const QgsCoordinateReferenceSystem &crs )
  QgsRectangle rect;
  if ( !mSettings.visibleExtent().isEmpty() )
  {
-    QgsCoordinateTransform transform( mSettings.destinationCrs(), crs );
+    QgsCoordinateTransform transform( mSettings.destinationCrs(), crs, QgsProject::instance() );
    try
    {
      rect = transform.transformBoundingBox( mSettings.visibleExtent() );
--- a/src/gui/qgsmapcanvasannotationitem.cpp
+++ b/src/gui/qgsmapcanvasannotationitem.cpp
@ -60,7 +60,7 @@ void QgsMapCanvasAnnotationItem::updatePosition()

  if ( mAnnotation->hasFixedMapPosition() )
  {
-    QgsCoordinateTransform t( mAnnotation->mapPositionCrs(), mMapCanvas->mapSettings().destinationCrs() );
+    QgsCoordinateTransform t( mAnnotation->mapPositionCrs(), mMapCanvas->mapSettings().destinationCrs(), QgsProject::instance() );
    QgsPointXY coord = mAnnotation->mapPosition();
    try
    {
@ -144,7 +144,7 @@ void QgsMapCanvasAnnotationItem::setFeatureForMapPosition()

  try
  {
-    QgsCoordinateTransform ct( mAnnotation->mapPositionCrs(), mMapCanvas->mapSettings().destinationCrs() );
+    QgsCoordinateTransform ct( mAnnotation->mapPositionCrs(), mMapCanvas->mapSettings().destinationCrs(), QgsProject::instance() );
    if ( ct.isValid() )
      mapPosition = ct.transform( mapPosition );
  }
--- a/src/gui/qgsrasterlayersaveasdialog.cpp
+++ b/src/gui/qgsrasterlayersaveasdialog.cpp
@ -25,6 +25,7 @@
 #include "qgssettings.h"
 #include "qgsrasterfilewriter.h"
 #include "cpl_string.h"
+#include "qgsproject.h"
 #include <gdal.h>

 #include <QFileDialog>
@ -448,7 +449,7 @@ void QgsRasterLayerSaveAsDialog::setResolution( double xRes, double yRes, const
    // TODO: consider more precise resolution calculation

    QgsPointXY center = outputRectangle().center();
-    QgsCoordinateTransform ct( srcCrs, outputCrs() );
+    QgsCoordinateTransform ct( srcCrs, outputCrs(), QgsProject::instance() );
    QgsPointXY srsCenter = ct.transform( center, QgsCoordinateTransform::ReverseTransform );

    QgsRectangle srcExtent( srsCenter.x() - xRes / 2, srsCenter.y() - yRes / 2, srsCenter.x() + xRes / 2, srsCenter.y() + yRes / 2 );
--- a/src/gui/qgsrubberband.cpp
+++ b/src/gui/qgsrubberband.cpp
@ -19,6 +19,7 @@
 #include "qgslogger.h"
 #include "qgsmapcanvas.h"
 #include "qgsvectorlayer.h"
+#include "qgsproject.h"
 #include <QPainter>

 QgsRubberBand::QgsRubberBand( QgsMapCanvas *mapCanvas, QgsWkbTypes::GeometryType geometryType )
@ -257,7 +258,7 @@ void QgsRubberBand::addGeometry( const QgsGeometry &geometry, const QgsCoordinat
  QgsGeometry geom = geometry;
  if ( crs.isValid() )
  {
-    QgsCoordinateTransform ct( crs, ms.destinationCrs() );
+    QgsCoordinateTransform ct( crs, ms.destinationCrs(), QgsProject::instance() );
    geom.transform( ct );
  }

--- a/src/plugins/grass/qgsgrassnewmapset.cpp
+++ b/src/plugins/grass/qgsgrassnewmapset.cpp
@ -520,7 +520,7 @@ void QgsGrassNewMapset::setRegionPage()
  if ( mRegionModified && newCrs.isValid() && mCrs.isValid()
       && newCrs.srsid() != mCrs.srsid() )
  {
-    QgsCoordinateTransform trans( mCrs, newCrs );
+    QgsCoordinateTransform trans( mCrs, newCrs, QgsProject::instance() );

    double n = mNorthLineEdit->text().toDouble();
    double s = mSouthLineEdit->text().toDouble();
@ -856,7 +856,7 @@ void QgsGrassNewMapset::setSelectedRegion()
      return;
    }

-    QgsCoordinateTransform trans( source, dest );
+    QgsCoordinateTransform trans( source, dest, QgsProject::instance() );

    bool ok = true;
    for ( int i = 0; i < 4; i++ )
@ -946,7 +946,7 @@ void QgsGrassNewMapset::setCurrentRegion()
  if ( srs.isValid() && mCrs.isValid()
       && srs.srsid() != mCrs.srsid() )
  {
-    QgsCoordinateTransform trans( srs, mCrs );
+    QgsCoordinateTransform trans( srs, mCrs, QgsProject::instance() );

    bool ok = true;
    for ( int i = 0; i < 2; i++ )
@ -1064,7 +1064,7 @@ void QgsGrassNewMapset::drawRegion()
      return;
    }

-    QgsCoordinateTransform trans( source, dest );
+    QgsCoordinateTransform trans( source, dest, QgsProject::instance() );

    for ( int i = points.size() - 1; i >= 0; i-- )
    {
--- a/src/providers/arcgisrest/qgsafsfeatureiterator.cpp
+++ b/src/providers/arcgisrest/qgsafsfeatureiterator.cpp
@ -41,7 +41,9 @@ QgsAfsFeatureIterator::QgsAfsFeatureIterator( QgsAfsFeatureSource *source, bool
 {
  if ( mRequest.destinationCrs().isValid() && mRequest.destinationCrs() != mSource->sharedData()->crs() )
  {
+    Q_NOWARN_DEPRECATED_PUSH
    mTransform = QgsCoordinateTransform( mSource->sharedData()->crs(), mRequest.destinationCrs() );
+    Q_NOWARN_DEPRECATED_POP
  }
  try
  {
--- a/src/providers/arcgisrest/qgsafsprovider.cpp
+++ b/src/providers/arcgisrest/qgsafsprovider.cpp
@ -89,7 +89,9 @@ QgsAfsProvider::QgsAfsProvider( const QString &uri )
      appendError( QgsErrorMessage( tr( "Could not parse spatial reference" ), QStringLiteral( "AFSProvider" ) ) );
      return;
    }
+    Q_NOWARN_DEPRECATED_PUSH
    mSharedData->mExtent = QgsCoordinateTransform( extentCrs, mSharedData->mSourceCRS ).transformBoundingBox( mSharedData->mExtent );
+    Q_NOWARN_DEPRECATED_POP
  }

  // Read fields
--- a/src/providers/arcgisrest/qgsarcgisservicesourceselect.cpp
+++ b/src/providers/arcgisrest/qgsarcgisservicesourceselect.cpp
@ -315,7 +315,9 @@ void QgsArcGisServiceSourceSelect::addButtonClicked()
  {
    try
    {
+      Q_NOWARN_DEPRECATED_PUSH
      extent = QgsCoordinateTransform( canvasCrs, pCrs ).transform( extent );
+      Q_NOWARN_DEPRECATED_POP
      QgsDebugMsg( QString( "canvas transform: Canvas CRS=%1, Provider CRS=%2, BBOX=%3" )
                   .arg( canvasCrs.authid(), pCrs.authid(), extent.asWktCoordinates() ) );
    }
--- a/src/providers/db2/qgsdb2featureiterator.cpp
+++ b/src/providers/db2/qgsdb2featureiterator.cpp
@ -36,7 +36,9 @@ QgsDb2FeatureIterator::QgsDb2FeatureIterator( QgsDb2FeatureSource *source, bool

  if ( mRequest.destinationCrs().isValid() && mRequest.destinationCrs() != mSource->mCrs )
  {
+    Q_NOWARN_DEPRECATED_PUSH
    mTransform = QgsCoordinateTransform( mSource->mCrs, mRequest.destinationCrs() );
+    Q_NOWARN_DEPRECATED_POP
  }
  try
  {
--- a/src/providers/delimitedtext/qgsdelimitedtextfeatureiterator.cpp
+++ b/src/providers/delimitedtext/qgsdelimitedtextfeatureiterator.cpp
@ -41,7 +41,9 @@ QgsDelimitedTextFeatureIterator::QgsDelimitedTextFeatureIterator( QgsDelimitedTe

  if ( mRequest.destinationCrs().isValid() && mRequest.destinationCrs() != mSource->mCrs )
  {
+    Q_NOWARN_DEPRECATED_PUSH
    mTransform = QgsCoordinateTransform( mSource->mCrs, mRequest.destinationCrs() );
+    Q_NOWARN_DEPRECATED_POP
  }
  try
  {
--- a/src/providers/gpx/qgsgpxfeatureiterator.cpp
+++ b/src/providers/gpx/qgsgpxfeatureiterator.cpp
@ -31,7 +31,9 @@ QgsGPXFeatureIterator::QgsGPXFeatureIterator( QgsGPXFeatureSource *source, bool
 {
  if ( mRequest.destinationCrs().isValid() && mRequest.destinationCrs() != mSource->mCrs )
  {
+    Q_NOWARN_DEPRECATED_PUSH
    mTransform = QgsCoordinateTransform( mSource->mCrs, mRequest.destinationCrs() );
+    Q_NOWARN_DEPRECATED_POP
  }
  try
  {
--- a/src/providers/mssql/qgsmssqlfeatureiterator.cpp
+++ b/src/providers/mssql/qgsmssqlfeatureiterator.cpp
@ -36,7 +36,9 @@ QgsMssqlFeatureIterator::QgsMssqlFeatureIterator( QgsMssqlFeatureSource *source,

  if ( mRequest.destinationCrs().isValid() && mRequest.destinationCrs() != mSource->mCrs )
  {
+    Q_NOWARN_DEPRECATED_PUSH
    mTransform = QgsCoordinateTransform( mSource->mCrs, mRequest.destinationCrs() );
+    Q_NOWARN_DEPRECATED_POP
  }
  try
  {
--- a/src/providers/ogr/qgsogrfeatureiterator.cpp
+++ b/src/providers/ogr/qgsogrfeatureiterator.cpp
@ -79,7 +79,9 @@ QgsOgrFeatureIterator::QgsOgrFeatureIterator( QgsOgrFeatureSource *source, bool

  if ( mRequest.destinationCrs().isValid() && mRequest.destinationCrs() != mSource->mCrs )
  {
+    Q_NOWARN_DEPRECATED_PUSH
    mTransform = QgsCoordinateTransform( mSource->mCrs, mRequest.destinationCrs() );
+    Q_NOWARN_DEPRECATED_POP
  }
  try
  {
--- a/src/providers/postgres/qgspostgresfeatureiterator.cpp
+++ b/src/providers/postgres/qgspostgresfeatureiterator.cpp
@ -63,7 +63,9 @@ QgsPostgresFeatureIterator::QgsPostgresFeatureIterator( QgsPostgresFeatureSource

  if ( mRequest.destinationCrs().isValid() && mRequest.destinationCrs() != mSource->mCrs )
  {
+    Q_NOWARN_DEPRECATED_PUSH
    mTransform = QgsCoordinateTransform( mSource->mCrs, mRequest.destinationCrs() );
+    Q_NOWARN_DEPRECATED_POP
  }
  try
  {
--- a/src/providers/spatialite/qgsspatialitefeatureiterator.cpp
+++ b/src/providers/spatialite/qgsspatialitefeatureiterator.cpp
@ -44,7 +44,9 @@ QgsSpatiaLiteFeatureIterator::QgsSpatiaLiteFeatureIterator( QgsSpatiaLiteFeature

  if ( mRequest.destinationCrs().isValid() && mRequest.destinationCrs() != mSource->mCrs )
  {
+    Q_NOWARN_DEPRECATED_PUSH
    mTransform = QgsCoordinateTransform( mSource->mCrs, mRequest.destinationCrs() );
+    Q_NOWARN_DEPRECATED_POP
  }
  try
  {
--- a/src/providers/virtual/qgsvirtuallayerfeatureiterator.cpp
+++ b/src/providers/virtual/qgsvirtuallayerfeatureiterator.cpp
@ -45,7 +45,9 @@ QgsVirtualLayerFeatureIterator::QgsVirtualLayerFeatureIterator( QgsVirtualLayerF

  if ( mRequest.destinationCrs().isValid() && mRequest.destinationCrs() != mSource->mCrs )
  {
+    Q_NOWARN_DEPRECATED_PUSH
    mTransform = QgsCoordinateTransform( mSource->mCrs, mRequest.destinationCrs() );
+    Q_NOWARN_DEPRECATED_POP
  }
  try
  {
--- a/src/providers/wcs/qgswcsprovider.cpp
+++ b/src/providers/wcs/qgswcsprovider.cpp
@ -1068,8 +1068,9 @@ bool QgsWcsProvider::calculateExtent() const
      //QgsDebugMsg( "qgisSrsSource: " + qgisSrsSource.toWkt() );
      //QgsDebugMsg( "qgisSrsDest: " + qgisSrsDest.toWkt() );

+      Q_NOWARN_DEPRECATED_PUSH
      mCoordinateTransform = QgsCoordinateTransform( qgisSrsSource, qgisSrsDest );
-
+      Q_NOWARN_DEPRECATED_POP
    }

    QgsDebugMsg( "mCoverageSummary.wgs84BoundingBox= " + mCoverageSummary.wgs84BoundingBox.toString() );
--- a/src/providers/wfs/qgswfscapabilities.cpp
+++ b/src/providers/wfs/qgswfscapabilities.cpp
@ -458,7 +458,10 @@ void QgsWfsCapabilities::capabilitiesReplyFinished()
          // If the CRS is projected then check that projecting the corner of the bbox, assumed to be in WGS84,
          // into the CRS, and then back to WGS84, works (check that we are in the validity area)
          QgsCoordinateReferenceSystem crsWGS84 = QgsCoordinateReferenceSystem::fromOgcWmsCrs( QStringLiteral( "CRS:84" ) );
+
+          Q_NOWARN_DEPRECATED_PUSH
          QgsCoordinateTransform ct( crsWGS84, crs );
+          Q_NOWARN_DEPRECATED_POP

          QgsPointXY ptMin( featureType.bbox.xMinimum(), featureType.bbox.yMinimum() );
          QgsPointXY ptMinBack( ct.transform( ct.transform( ptMin, QgsCoordinateTransform::ForwardTransform ), QgsCoordinateTransform::ReverseTransform ) );
--- a/src/providers/wfs/qgswfsfeatureiterator.cpp
+++ b/src/providers/wfs/qgswfsfeatureiterator.cpp
@ -815,7 +815,9 @@ QgsWFSFeatureIterator::QgsWFSFeatureIterator( QgsWFSFeatureSource *source,
 {
  if ( mRequest.destinationCrs().isValid() && mRequest.destinationCrs() != mSource->mCrs )
  {
+    Q_NOWARN_DEPRECATED_PUSH
    mTransform = QgsCoordinateTransform( mSource->mCrs, mRequest.destinationCrs() );
+    Q_NOWARN_DEPRECATED_POP
  }
  try
  {
--- a/src/providers/wfs/qgswfsprovider.cpp
+++ b/src/providers/wfs/qgswfsprovider.cpp
@ -1565,7 +1565,9 @@ bool QgsWFSProvider::getCapabilities()
        if ( mShared->mCaps.featureTypes[i].bboxSRSIsWGS84 )
        {
          QgsCoordinateReferenceSystem src = QgsCoordinateReferenceSystem::fromOgcWmsCrs( QStringLiteral( "CRS:84" ) );
+          Q_NOWARN_DEPRECATED_PUSH
          QgsCoordinateTransform ct( src, mShared->mSourceCRS );
+          Q_NOWARN_DEPRECATED_POP

          QgsDebugMsg( "latlon ext:" + r.toString() );
          QgsDebugMsg( "src:" + src.authid() );
--- a/src/providers/wms/qgswmscapabilities.cpp
+++ b/src/providers/wms/qgswmscapabilities.cpp
@ -829,7 +829,9 @@ void QgsWmsCapabilities::parseLayer( QDomElement const &e, QgsWmsLayerProperty &

            QgsCoordinateReferenceSystem dst = QgsCoordinateReferenceSystem::fromOgcWmsCrs( DEFAULT_LATLON_CRS );

+            Q_NOWARN_DEPRECATED_PUSH
            QgsCoordinateTransform ct( src, dst );
+            Q_NOWARN_DEPRECATED_POP
            layerProperty.ex_GeographicBoundingBox = ct.transformBoundingBox( layerProperty.ex_GeographicBoundingBox );
          }
          catch ( QgsCsException &cse )
--- a/src/providers/wms/qgswmsprovider.cpp
+++ b/src/providers/wms/qgswmsprovider.cpp
@ -1188,7 +1188,10 @@ void QgsWmsProvider::setupXyzCapabilities( const QString &uri )
  QgsDataSourceUri parsedUri;
  parsedUri.setEncodedUri( uri );

+  Q_NOWARN_DEPRECATED_PUSH
  QgsCoordinateTransform ct( QgsCoordinateReferenceSystem( QStringLiteral( "EPSG:4326" ) ), QgsCoordinateReferenceSystem( mSettings.mCrsId ) );
+  Q_NOWARN_DEPRECATED_POP
+
  // the whole world is projected to a square:
  // X going from 180 W to 180 E
  // Y going from ~85 N to ~85 S  (=atan(sinh(pi)) ... to get a square)
@ -1318,7 +1321,10 @@ bool QgsWmsProvider::extentForNonTiledLayer( const QString &layerName, const QSt
  if ( !wgs.isValid() || !dst.isValid() )
    return false;

+  Q_NOWARN_DEPRECATED_PUSH
  QgsCoordinateTransform xform( wgs, dst );
+  Q_NOWARN_DEPRECATED_POP
+
  QgsDebugMsg( QString( "transforming layer extent %1" ).arg( extent.toString( true ) ) );
  try
  {
@ -1548,7 +1554,9 @@ bool QgsWmsProvider::calculateExtent() const
        {
          QgsCoordinateReferenceSystem qgisSrsSource = QgsCoordinateReferenceSystem::fromOgcWmsCrs( mTileLayer->boundingBoxes[i].crs );

+          Q_NOWARN_DEPRECATED_PUSH
          QgsCoordinateTransform ct( qgisSrsSource, qgisSrsDest );
+          Q_NOWARN_DEPRECATED_POP

          QgsDebugMsg( QString( "ct: %1 => %2" ).arg( mTileLayer->boundingBoxes.at( i ).crs, mImageCrs ) );

@ -2928,7 +2936,9 @@ QgsRasterIdentifyResult QgsWmsProvider::identify( const QgsPointXY &point, QgsRa
          QgsCoordinateTransform coordinateTransform;
          if ( featuresCrs.isValid() && featuresCrs != crs() )
          {
+            Q_NOWARN_DEPRECATED_PUSH
            coordinateTransform = QgsCoordinateTransform( featuresCrs, crs() );
+            Q_NOWARN_DEPRECATED_POP
          }
          QgsFeatureStore featureStore( fields, crs() );
          QMap<QString, QVariant> params;
@ -3004,7 +3014,9 @@ QgsRasterIdentifyResult QgsWmsProvider::identify( const QgsPointXY &point, QgsRa

            if ( featuresCrs.isValid() && featuresCrs != crs() )
            {
+              Q_NOWARN_DEPRECATED_PUSH
              coordinateTransform = QgsCoordinateTransform( featuresCrs, crs() );
+              Q_NOWARN_DEPRECATED_POP
            }
          }

--- a/src/server/qgsconfigparserutils.cpp
+++ b/src/server/qgsconfigparserutils.cpp
@ -105,7 +105,9 @@ void QgsConfigParserUtils::appendLayerBoundingBoxes( QDomElement &layerElem, QDo
  QgsRectangle wgs84BoundingRect;
  if ( !layerExtent.isNull() )
  {
+    Q_NOWARN_DEPRECATED_PUSH
    QgsCoordinateTransform exGeoTransform( layerCRS, wgs84 );
+    Q_NOWARN_DEPRECATED_POP
    try
    {
      wgs84BoundingRect = exGeoTransform.transformBoundingBox( layerExtent );
@ -213,7 +215,9 @@ void QgsConfigParserUtils::appendLayerBoundingBox( QDomElement &layerElem, QDomD
  QgsRectangle crsExtent;
  if ( !layerExtent.isNull() )
  {
+    Q_NOWARN_DEPRECATED_PUSH
    QgsCoordinateTransform crsTransform( layerCRS, crs );
+    Q_NOWARN_DEPRECATED_POP
    try
    {
      crsExtent = crsTransform.transformBoundingBox( layerExtent );
--- a/src/server/services/wcs/qgswcsgetcoverage.cpp
+++ b/src/server/services/wcs/qgswcsgetcoverage.cpp
@ -161,7 +161,9 @@ namespace QgsWcs
    // transform rect
    if ( requestCRS != rLayer->crs() )
    {
+      Q_NOWARN_DEPRECATED_PUSH
      QgsCoordinateTransform t( requestCRS, rLayer->crs() );
+      Q_NOWARN_DEPRECATED_POP
      rect = t.transformBoundingBox( rect );
    }

--- a/src/server/services/wcs/qgswcsutils.cpp
+++ b/src/server/services/wcs/qgswcsutils.cpp
@ -73,7 +73,9 @@ namespace QgsWcs

    //lonLatEnvelope
    QgsCoordinateReferenceSystem layerCrs = layer->crs();
+    Q_NOWARN_DEPRECATED_PUSH
    QgsCoordinateTransform t( layerCrs, QgsCoordinateReferenceSystem( 4326 ) );
+    Q_NOWARN_DEPRECATED_POP
    //transform
    QgsRectangle BBox;
    try
--- a/src/server/services/wfs/qgswfsgetcapabilities.cpp
+++ b/src/server/services/wfs/qgswfsgetcapabilities.cpp
@ -515,7 +515,9 @@ namespace QgsWfs
      QgsRectangle wgs84BoundingRect;
      if ( !layerExtent.isNull() )
      {
+        Q_NOWARN_DEPRECATED_PUSH
        QgsCoordinateTransform exGeoTransform( layer->crs(), wgs84 );
+        Q_NOWARN_DEPRECATED_POP
        try
        {
          wgs84BoundingRect = exGeoTransform.transformBoundingBox( layerExtent );
--- a/src/server/services/wfs/qgswfsgetfeature.cpp
+++ b/src/server/services/wfs/qgswfsgetfeature.cpp
@ -154,7 +154,9 @@ namespace QgsWfs
        }
        else
        {
+          Q_NOWARN_DEPRECATED_PUSH
          QgsCoordinateTransform transform( layer->crs(), requestCrs );
+          Q_NOWARN_DEPRECATED_POP
          try
          {
            if ( requestRect.isEmpty() )
@ -1223,7 +1225,9 @@ namespace QgsWfs

        int prec = params.precision;
        QgsCoordinateReferenceSystem crs = params.crs;
+        Q_NOWARN_DEPRECATED_PUSH
        QgsCoordinateTransform mTransform( crs, params.outputCrs );
+        Q_NOWARN_DEPRECATED_POP
        try
        {
          QgsGeometry transformed = geom;
@ -1324,7 +1328,9 @@ namespace QgsWfs

        int prec = params.precision;
        QgsCoordinateReferenceSystem crs = params.crs;
+        Q_NOWARN_DEPRECATED_PUSH
        QgsCoordinateTransform mTransform( crs, params.outputCrs );
+        Q_NOWARN_DEPRECATED_POP
        try
        {
          QgsGeometry transformed = geom;
--- a/src/server/services/wms/qgswmsgetcapabilities.cpp
+++ b/src/server/services/wms/qgswmsgetcapabilities.cpp
@ -1250,7 +1250,9 @@ namespace QgsWms
      QgsRectangle wgs84BoundingRect;
      if ( !layerExtent.isNull() )
      {
+        Q_NOWARN_DEPRECATED_PUSH
        QgsCoordinateTransform exGeoTransform( layerCRS, wgs84 );
+        Q_NOWARN_DEPRECATED_POP
        try
        {
          wgs84BoundingRect = exGeoTransform.transformBoundingBox( layerExtent );
@ -1342,7 +1344,9 @@ namespace QgsWms
      QgsRectangle crsExtent;
      if ( !layerExtent.isNull() )
      {
+        Q_NOWARN_DEPRECATED_PUSH
        QgsCoordinateTransform crsTransform( layerCRS, crs );
+        Q_NOWARN_DEPRECATED_POP
        try
        {
          crsExtent = crsTransform.transformBoundingBox( layerExtent );
@ -1455,7 +1459,9 @@ namespace QgsWms
      }

      //get project crs
+      Q_NOWARN_DEPRECATED_PUSH
      QgsCoordinateTransform t( layerCrs, project->crs() );
+      Q_NOWARN_DEPRECATED_POP

      //transform
      try
--- a/src/server/services/wms/qgswmsgetcontext.cpp
+++ b/src/server/services/wms/qgswmsgetcontext.cpp
@ -405,7 +405,9 @@ namespace QgsWms
          // update combineBBox
          try
          {
+            Q_NOWARN_DEPRECATED_PUSH
            QgsCoordinateTransform t( l->crs(), project->crs() );
+            Q_NOWARN_DEPRECATED_POP
            QgsRectangle BBox = t.transformBoundingBox( l->extent() );
            if ( combinedBBox.isEmpty() )
            {
--- a/tests/src/app/testqgsmeasuretool.cpp
+++ b/tests/src/app/testqgsmeasuretool.cpp
@ -129,7 +129,7 @@ void TestQgsMeasureTool::testLengthCalculation()
  // check new CoordinateReferenceSystem, points must be reprojected to paint them successfully (issue #15182)
  QgsCoordinateReferenceSystem srs2( 4326, QgsCoordinateReferenceSystem::EpsgCrsId );

-  QgsCoordinateTransform ct( srs, srs2 );
+  QgsCoordinateTransform ct( srs, srs2, QgsProject::instance() );

  QgsPointXY p0 = ct.transform( tool2->points()[0] );
  QgsPointXY p1 = ct.transform( tool2->points()[1] );
--- a/tests/src/core/testqgscoordinatetransform.cpp
+++ b/tests/src/core/testqgscoordinatetransform.cpp
@ -18,6 +18,7 @@
 #include "qgsapplication.h"
 #include "qgsrectangle.h"
 #include "qgscoordinatetransformcontext.h"
+#include "qgsproject.h"
 #include <QObject>
 #include "qgstest.h"
 #include "qgsexception.h"
@ -64,7 +65,7 @@ void TestQgsCoordinateTransform::copy()
  QgsCoordinateReferenceSystem destination;
  destination.createFromId( 4326, QgsCoordinateReferenceSystem::EpsgCrsId );

-  QgsCoordinateTransform original( source, destination );
+  QgsCoordinateTransform original( source, destination, QgsProject::instance() );
  QVERIFY( original.isValid() );

  QgsCoordinateTransform copy( original );
@ -93,7 +94,7 @@ void TestQgsCoordinateTransform::assignment()
  QgsCoordinateReferenceSystem destination;
  destination.createFromId( 4326, QgsCoordinateReferenceSystem::EpsgCrsId );

-  QgsCoordinateTransform original( source, destination );
+  QgsCoordinateTransform original( source, destination, QgsProject::instance() );
  QVERIFY( original.isValid() );

  QgsCoordinateTransform copy;
@ -127,22 +128,22 @@ void TestQgsCoordinateTransform::isValid()
  srs2.createFromSrid( 4326 );

  // valid source, invalid destination
-  QgsCoordinateTransform tr2( srs1, QgsCoordinateReferenceSystem() );
+  QgsCoordinateTransform tr2( srs1, QgsCoordinateReferenceSystem(), QgsProject::instance() );
  QVERIFY( !tr2.isValid() );

  // invalid source, valid destination
-  QgsCoordinateTransform tr3( QgsCoordinateReferenceSystem(), srs2 );
+  QgsCoordinateTransform tr3( QgsCoordinateReferenceSystem(), srs2, QgsProject::instance() );
  QVERIFY( !tr3.isValid() );

  // valid source, valid destination
-  QgsCoordinateTransform tr4( srs1, srs2 );
+  QgsCoordinateTransform tr4( srs1, srs2, QgsProject::instance() );
  QVERIFY( tr4.isValid() );

  // try to invalidate by setting source as invalid
  tr4.setSourceCrs( QgsCoordinateReferenceSystem() );
  QVERIFY( !tr4.isValid() );

-  QgsCoordinateTransform tr5( srs1, srs2 );
+  QgsCoordinateTransform tr5( srs1, srs2, QgsProject::instance() );
  // try to invalidate by setting destination as invalid
  tr5.setDestinationCrs( QgsCoordinateReferenceSystem() );
  QVERIFY( !tr5.isValid() );
@ -160,19 +161,19 @@ void TestQgsCoordinateTransform::isShortCircuited()
  srs2.createFromSrid( 4326 );

  // valid source, invalid destination
-  QgsCoordinateTransform tr2( srs1, QgsCoordinateReferenceSystem() );
+  QgsCoordinateTransform tr2( srs1, QgsCoordinateReferenceSystem(), QgsProject::instance() );
  QVERIFY( tr2.isShortCircuited() );

  // invalid source, valid destination
-  QgsCoordinateTransform tr3( QgsCoordinateReferenceSystem(), srs2 );
+  QgsCoordinateTransform tr3( QgsCoordinateReferenceSystem(), srs2, QgsProject::instance() );
  QVERIFY( tr3.isShortCircuited() );

  // equal, valid source and destination
-  QgsCoordinateTransform tr4( srs1, srs1 );
+  QgsCoordinateTransform tr4( srs1, srs1, QgsProject::instance() );
  QVERIFY( tr4.isShortCircuited() );

  // valid but different source and destination
-  QgsCoordinateTransform tr5( srs1, srs2 );
+  QgsCoordinateTransform tr5( srs1, srs2, QgsProject::instance() );
  QVERIFY( !tr5.isShortCircuited() );

  // try to short circuit by changing dest
@ -221,7 +222,7 @@ void TestQgsCoordinateTransform::transformBoundingBox()
  QgsCoordinateReferenceSystem destSrs;
  destSrs.createFromSrid( 4326 );

-  QgsCoordinateTransform tr( sourceSrs, destSrs );
+  QgsCoordinateTransform tr( sourceSrs, destSrs, QgsProject::instance() );
  QgsRectangle crossingRect( 6374985, -3626584, 7021195, -3272435 );
  QgsRectangle resultRect = tr.transformBoundingBox( crossingRect, QgsCoordinateTransform::ForwardTransform, true );
  QgsRectangle expectedRect;
--- a/tests/src/core/testqgsexpression.cpp
+++ b/tests/src/core/testqgsexpression.cpp
@ -2231,7 +2231,7 @@ class TestQgsExpression: public QObject
      s.createFromOgcWmsCrs( QStringLiteral( "EPSG:4326" ) );
      QgsCoordinateReferenceSystem d;
      d.createFromOgcWmsCrs( QStringLiteral( "EPSG:3857" ) );
-      QgsCoordinateTransform t( s, d );
+      QgsCoordinateTransform t( s, d, QgsProject::instance() );

      QgsGeometry tLine = QgsGeometry::fromPolylineXY( line );
      tLine.transform( t );
--- a/tests/src/core/testqgsgeometry.cpp
+++ b/tests/src/core/testqgsgeometry.cpp
@ -49,6 +49,7 @@
 #include "qgsgeometrycollection.h"
 #include "qgsgeometryfactory.h"
 #include "qgscurvepolygon.h"
+#include "qgsproject.h"

 //qgs unit test utility class
 #include "qgsrenderchecker.h"
@ -715,7 +716,7 @@ void TestQgsGeometry::point()
  sourceSrs.createFromSrid( 3994 );
  QgsCoordinateReferenceSystem destSrs;
  destSrs.createFromSrid( 4202 ); // want a transform with ellipsoid change
-  QgsCoordinateTransform tr( sourceSrs, destSrs );
+  QgsCoordinateTransform tr( sourceSrs, destSrs, QgsProject::instance() );
  QgsPoint p16( QgsWkbTypes::PointZM, 6374985, -3626584, 1, 2 );
  p16.transform( tr, QgsCoordinateTransform::ForwardTransform );
  QGSCOMPARENEAR( p16.x(), 175.771, 0.001 );
@ -1593,7 +1594,7 @@ void TestQgsGeometry::circularString()
  sourceSrs.createFromSrid( 3994 );
  QgsCoordinateReferenceSystem destSrs;
  destSrs.createFromSrid( 4202 ); // want a transform with ellipsoid change
-  QgsCoordinateTransform tr( sourceSrs, destSrs );
+  QgsCoordinateTransform tr( sourceSrs, destSrs, QgsProject::instance() );

  // 2d CRS transform
  QgsCircularString l21;
@ -3317,7 +3318,7 @@ void TestQgsGeometry::lineString()
  sourceSrs.createFromSrid( 3994 );
  QgsCoordinateReferenceSystem destSrs;
  destSrs.createFromSrid( 4202 ); // want a transform with ellipsoid change
-  QgsCoordinateTransform tr( sourceSrs, destSrs );
+  QgsCoordinateTransform tr( sourceSrs, destSrs, QgsProject::instance() );

  // 2d CRS transform
  QgsLineString l21;
@ -5154,7 +5155,7 @@ void TestQgsGeometry::polygon()
  sourceSrs.createFromSrid( 3994 );
  QgsCoordinateReferenceSystem destSrs;
  destSrs.createFromSrid( 4202 ); // want a transform with ellipsoid change
-  QgsCoordinateTransform tr( sourceSrs, destSrs );
+  QgsCoordinateTransform tr( sourceSrs, destSrs, QgsProject::instance() );

  // 2d CRS transform
  QgsPolygon pTransform;
@ -9390,7 +9391,7 @@ void TestQgsGeometry::compoundCurve()
  sourceSrs.createFromSrid( 3994 );
  QgsCoordinateReferenceSystem destSrs;
  destSrs.createFromSrid( 4202 ); // want a transform with ellipsoid change
-  QgsCoordinateTransform tr( sourceSrs, destSrs );
+  QgsCoordinateTransform tr( sourceSrs, destSrs, QgsProject::instance() );

  // 2d CRS transform
  QgsCompoundCurve c21;
@ -14206,7 +14207,7 @@ void TestQgsGeometry::geometryCollection()
  sourceSrs.createFromSrid( 3994 );
  QgsCoordinateReferenceSystem destSrs;
  destSrs.createFromSrid( 4202 ); // want a transform with ellipsoid change
-  QgsCoordinateTransform tr( sourceSrs, destSrs );
+  QgsCoordinateTransform tr( sourceSrs, destSrs, QgsProject::instance() );

  // 2d CRS transform
  QgsGeometryCollection pTransform;
--- a/tests/src/core/testqgstracer.cpp
+++ b/tests/src/core/testqgstracer.cpp
@ -19,6 +19,7 @@
 #include <qgsgeometry.h>
 #include <qgstracer.h>
 #include <qgsvectorlayer.h>
+#include "qgsproject.h"

 class TestQgsTracer : public QObject
 {
@ -306,7 +307,7 @@ void TestQgsTracer::testReprojection()
  QgsVectorLayer *vl = make_layer( wkts );

  QgsCoordinateReferenceSystem dstCrs( QStringLiteral( "EPSG:3857" ) );
-  QgsCoordinateTransform ct( QgsCoordinateReferenceSystem( QStringLiteral( "EPSG:4326" ) ), dstCrs );
+  QgsCoordinateTransform ct( QgsCoordinateReferenceSystem( QStringLiteral( "EPSG:4326" ) ), dstCrs, QgsProject::instance() );
  QgsPointXY p1 = ct.transform( QgsPointXY( 1, 0 ) );
  QgsPointXY p2 = ct.transform( QgsPointXY( 2, 0 ) );

--- a/tests/src/python/test_qgscoordinatetransform.py
+++ b/tests/src/python/test_qgscoordinatetransform.py
@ -33,7 +33,7 @@ class TestQgsCoordinateTransform(unittest.TestCase):
        myGeoCrs.createFromId(4326, QgsCoordinateReferenceSystem.EpsgCrsId)
        myUtmCrs = QgsCoordinateReferenceSystem()
        myUtmCrs.createFromId(32756, QgsCoordinateReferenceSystem.EpsgCrsId)
-        myXForm = QgsCoordinateTransform(myUtmCrs, myGeoCrs)
+        myXForm = QgsCoordinateTransform(myUtmCrs, myGeoCrs, QgsProject.instance())
        myProjectedExtent = myXForm.transformBoundingBox(myExtent)
        myExpectedExtent = ('150.1509239873580270,-35.7176936443908772 : '
                            '150.1964384662953194,-35.6971885216629090')
--- a/tests/src/python/test_qgsvectorfilewriter.py
+++ b/tests/src/python/test_qgsvectorfilewriter.py
@ -25,6 +25,7 @@ from qgis.core import (QgsVectorLayer,
                       QgsCoordinateReferenceSystem,
                       QgsVectorFileWriter,
                       QgsFeatureRequest,
+                       QgsProject,
                       QgsWkbTypes,
                       QgsRectangle,
                       QgsCoordinateTransform
@ -221,7 +222,7 @@ class TestQgsVectorFileWriter(unittest.TestCase):
        options = QgsVectorFileWriter.SaveVectorOptions()
        options.driverName = 'ESRI Shapefile'
        options.filterExtent = QgsRectangle(-12511460, 3045157, -10646621, 4683497)
-        options.ct = QgsCoordinateTransform(source_layer.crs(), QgsCoordinateReferenceSystem.fromEpsgId(3785))
+        options.ct = QgsCoordinateTransform(source_layer.crs(), QgsCoordinateReferenceSystem.fromEpsgId(3785), QgsProject.instance())

        dest_file_name = os.path.join(str(QDir.tempPath()), 'extent_transform.shp')
        write_result, error_message = QgsVectorFileWriter.writeAsVectorFormat(