Fix QgsCsException messages (LTR backport)

src/core/proj/qgscoordinatereferencesystem.cpp

@@ -1627,7 +1627,11 @@ void QgsCoordinateReferenceSystem::setProjString( const QString &proj4String )
   {
 #ifdef QGISDEBUG
     const int errNo = proj_context_errno( ctx );
+#if PROJ_VERSION_MAJOR>=8
+    QgsDebugError( QStringLiteral( "proj string rejected: %1" ).arg( proj_context_errno_string( ctx, errNo ) ) );
+#else
     QgsDebugError( QStringLiteral( "proj string rejected: %1" ).arg( proj_errno_string( errNo ) ) );
+#endif
 #endif
     d->mIsValid = false;
   }

src/core/proj/qgscoordinatetransform.cpp

@@ -818,6 +818,7 @@ void QgsCoordinateTransform::transformCoords( int numPoints, double *x, double *
   }
 
   mFallbackOperationOccurred = false;
+  bool errorOccurredDuringFallbackOperation = false;
   if ( actualRes != 0
        && ( d->mAvailableOpCount > 1 || d->mAvailableOpCount == -1 ) // only use fallbacks if more than one operation is possible -- otherwise we've already tried it and it failed
        && ( d->mAllowFallbackTransforms || mBallparkTransformsAreAppropriate ) )
@@ -842,13 +843,14 @@ void QgsCoordinateTransform::transformCoords( int numPoints, double *x, double *
       // So here just check proj_errno() for single point transform
       if ( numPoints == 1 )
       {
+        projResult = proj_errno( transform );
         // hmm - something very odd here. We can't trust proj_errno( transform ), as that's giving us incorrect error numbers
         // (such as "failed to load datum shift file", which is definitely incorrect for a default proj created operation!)
         // so we resort to testing values ourselves...
-        projResult = std::isinf( xprev[0] ) || std::isinf( yprev[0] ) || std::isinf( zprev[0] ) ? 1 : 0;
+        errorOccurredDuringFallbackOperation = std::isinf( xprev[0] ) || std::isinf( yprev[0] ) || std::isinf( zprev[0] );
       }
 
-      if ( projResult == 0 )
+      if ( !errorOccurredDuringFallbackOperation )
       {
         memcpy( x, xprev.data(), sizeof( double ) * numPoints );
         memcpy( y, yprev.data(), sizeof( double ) * numPoints );
@@ -873,25 +875,33 @@ void QgsCoordinateTransform::transformCoords( int numPoints, double *x, double *
     z[pos] = std::numeric_limits<double>::quiet_NaN();
   }
 
-  if ( projResult != 0 )
+  if ( projResult != 0 || errorOccurredDuringFallbackOperation )
   {
     //something bad happened....
     QString points;
 
+    const QChar delim = numPoints > 1 ? '\n' : ' ';
     for ( int i = 0; i < numPoints; ++i )
     {
-      points += QStringLiteral( "(%1, %2)\n" ).arg( x[i], 0, 'f' ).arg( y[i], 0, 'f' );
+      points += QStringLiteral( "(%1, %2)" ).arg( xprev[i], 0, 'f' ).arg( yprev[i], 0, 'f' ) + delim;
     }
 
-    const QString dir = ( direction == Qgis::TransformDirection::Forward ) ? QObject::tr( "forward transform" ) : QObject::tr( "inverse transform" );
+    const QString dir = ( direction == Qgis::TransformDirection::Forward ) ? QObject::tr( "Forward transform" ) : QObject::tr( "Inverse transform" );
 
-    const QString msg = QObject::tr( "%1 of\n"
-                                     "%2"
-                                     "Error: %3" )
+#if PROJ_VERSION_MAJOR>=8
+    PJ_CONTEXT *projContext = QgsProjContext::get();
+    const QString projError = !errorOccurredDuringFallbackOperation ? QString::fromUtf8( proj_context_errno_string( projContext, projResult ) ) : QObject::tr( "Fallback transform failed" );
+#else
+    const QString projError = !errorOccurredDuringFallbackOperation ? QString::fromUtf8( proj_errno_string( projResult ) ) : QObject::tr( "Fallback transform failed" );
+#endif
+
+    const QString msg = QObject::tr( "%1 (%2 to %3) of%4%5Error: %6" )
                         .arg( dir,
+                              ( direction == Qgis::TransformDirection::Forward ) ? d->mSourceCRS.authid() : d->mDestCRS.authid(),
+                              ( direction == Qgis::TransformDirection::Forward ) ? d->mDestCRS.authid() : d->mSourceCRS.authid(),
+                              QString( delim ),
                               points,
-                              projResult < 0 ? QString::fromUtf8( proj_errno_string( projResult ) ) : QObject::tr( "Fallback transform failed" ) );
-
+                              projError );
 
     // don't flood console with thousands of duplicate transform error messages
     if ( msg != mLastError )

src/core/proj/qgscoordinatetransform_p.cpp

@@ -329,12 +329,17 @@ ProjData QgsCoordinateTransformPrivate::threadLocalProjData()
       {
         // huh?
         const int errNo = proj_context_errno( context );
-        if ( errNo && errNo != -61 )
+        if ( errNo )
         {
+#if PROJ_VERSION_MAJOR>=8
+          nonAvailableError = QString( proj_context_errno_string( context, errNo ) );
+#else
           nonAvailableError = QString( proj_errno_string( errNo ) );
+#endif
         }
         else
         {
+          // in theory should never be hit!
           nonAvailableError = QObject::tr( "No coordinate operations are available between these two reference systems" );
         }
       }
@@ -463,9 +468,13 @@ ProjData QgsCoordinateTransformPrivate::threadLocalProjData()
   {
     const int errNo = proj_context_errno( context );
     const QStringList projErrors = errorLogger.errors();
-    if ( errNo && errNo != -61 )
+    if ( errNo )
     {
+#if PROJ_VERSION_MAJOR>=8
+      nonAvailableError = QString( proj_context_errno_string( context, errNo ) );
+#else
       nonAvailableError = QString( proj_errno_string( errNo ) );
+#endif
     }
     else if ( !projErrors.empty() )
     {

tests/src/python/test_qgscoordinatetransform.py

@@ -12,11 +12,14 @@
 import qgis  # NOQA
 
 from qgis.core import (
+    Qgis,
     QgsCoordinateReferenceSystem,
     QgsCoordinateTransform,
     QgsCoordinateTransformContext,
     QgsProject,
     QgsRectangle,
+    QgsPointXY,
+    QgsCsException
 )
 import unittest
 from qgis.testing import start_app, QgisTestCase
@@ -162,6 +165,22 @@ def testTransformBoundingBoxFullWorldToWebMercator(self):
         self.assertAlmostEqual(transformedExtent.xMaximum(), 20037508.343, delta=1e-3)
         self.assertAlmostEqual(transformedExtent.yMaximum(), 44927335.427, delta=1e-3)
 
+    def test_cs_exception(self):
+        ct = QgsCoordinateTransform(QgsCoordinateReferenceSystem('EPSG:4326'),
+                                    QgsCoordinateReferenceSystem('EPSG:3857'), QgsProject.instance())
+        point = QgsPointXY(-7603859, -7324441)
+        with self.assertRaises(QgsCsException) as e:
+            ct.transform(point)
+        self.assertEqual(str(e.exception), 'Forward transform (EPSG:4326 to EPSG:3857) of (-7603859.000000, -7324441.000000) Error: Invalid coordinate')
+
+        # reverse transform
+        ct = QgsCoordinateTransform(QgsCoordinateReferenceSystem('EPSG:3857'),
+                                    QgsCoordinateReferenceSystem('EPSG:4326'), QgsProject.instance())
+        point = QgsPointXY(-7603859, -7324441)
+        with self.assertRaises(QgsCsException) as e:
+            ct.transform(point, Qgis.TransformDirection.Reverse)
+        self.assertEqual(str(e.exception), 'Inverse transform (EPSG:4326 to EPSG:3857) of (-7603859.000000, -7324441.000000) Error: Invalid coordinate')
+
 
 if __name__ == '__main__':
     unittest.main()