Add validation to calls to QgsProject.setVerticalCrs

python/PyQt6/core/auto_generated/project/qgsproject.sip.in

@@ -360,7 +360,7 @@ The returned CRS will be invalid if the project has no vertical CRS.
 .. versionadded:: 3.38
 %End
 
-    void setVerticalCrs( const QgsCoordinateReferenceSystem &crs );
+    bool setVerticalCrs( const QgsCoordinateReferenceSystem &crs, QString *errorMessage /Out/ = 0 );
 %Docstring
 Sets the project's vertical coordinate reference system.
 
@@ -370,6 +370,13 @@ Sets the project's vertical coordinate reference system.
    :py:func:`~QgsProject.verticalCrs` will be the vertical component of :py:func:`~QgsProject.crs`. Otherwise it will be the value
    explicitly set by this call.
 
+:param crs: the vertical CRS
+
+
+:return: - ``True`` if vertical CRS was successfully set
+         - errorMessage: will be set to a descriptive message if the vertical CRS could not be set
+
+
 .. seealso:: :py:func:`verticalCrs`
 
 .. seealso:: :py:func:`setCrs`

python/core/auto_generated/project/qgsproject.sip.in

@@ -360,7 +360,7 @@ The returned CRS will be invalid if the project has no vertical CRS.
 .. versionadded:: 3.38
 %End
 
-    void setVerticalCrs( const QgsCoordinateReferenceSystem &crs );
+    bool setVerticalCrs( const QgsCoordinateReferenceSystem &crs, QString *errorMessage /Out/ = 0 );
 %Docstring
 Sets the project's vertical coordinate reference system.
 
@@ -370,6 +370,13 @@ Sets the project's vertical coordinate reference system.
    :py:func:`~QgsProject.verticalCrs` will be the vertical component of :py:func:`~QgsProject.crs`. Otherwise it will be the value
    explicitly set by this call.
 
+:param crs: the vertical CRS
+
+
+:return: - ``True`` if vertical CRS was successfully set
+         - errorMessage: will be set to a descriptive message if the vertical CRS could not be set
+
+
 .. seealso:: :py:func:`verticalCrs`
 
 .. seealso:: :py:func:`setCrs`

src/core/project/qgsproject.cpp

@@ -1021,14 +1021,66 @@ QgsCoordinateReferenceSystem QgsProject::verticalCrs() const
   return mVerticalCrs;
 }
 
-void QgsProject::setVerticalCrs( const QgsCoordinateReferenceSystem &crs )
+bool QgsProject::setVerticalCrs( const QgsCoordinateReferenceSystem &crs, QString *errorMessage )
 {
   QGIS_PROTECT_QOBJECT_THREAD_ACCESS
 
+  if ( crs.isValid() )
+  {
+    // validate that passed crs is a vertical crs
+    switch ( crs.type() )
+    {
+      case Qgis::CrsType::Vertical:
+        break;
+
+      case Qgis::CrsType::Unknown:
+      case Qgis::CrsType::Compound:
+      case Qgis::CrsType::Geodetic:
+      case Qgis::CrsType::Geocentric:
+      case Qgis::CrsType::Geographic2d:
+      case Qgis::CrsType::Geographic3d:
+      case Qgis::CrsType::Projected:
+      case Qgis::CrsType::Temporal:
+      case Qgis::CrsType::Engineering:
+      case Qgis::CrsType::Bound:
+      case Qgis::CrsType::Other:
+      case Qgis::CrsType::DerivedProjected:
+        if ( errorMessage )
+          *errorMessage = QObject::tr( "Specified CRS is a %1 CRS, not a Vertical CRS" ).arg( qgsEnumValueToKey( crs.type() ) );
+        return false;
+    }
+  }
+
   if ( crs != mVerticalCrs )
   {
     const QgsCoordinateReferenceSystem oldVerticalCrs = verticalCrs();
 
+    switch ( mCrs.type() )
+    {
+      case Qgis::CrsType::Compound:
+        if ( crs != oldVerticalCrs )
+        {
+          if ( errorMessage )
+            *errorMessage = QObject::tr( "Project CRS is a Compound CRS, specified Vertical CRS will be ignored" );
+          return false;
+        }
+        break;
+
+      case Qgis::CrsType::Unknown:
+      case Qgis::CrsType::Geodetic:
+      case Qgis::CrsType::Geocentric:
+      case Qgis::CrsType::Geographic2d:
+      case Qgis::CrsType::Geographic3d:
+      case Qgis::CrsType::Projected:
+      case Qgis::CrsType::Temporal:
+      case Qgis::CrsType::Engineering:
+      case Qgis::CrsType::Bound:
+      case Qgis::CrsType::Other:
+      case Qgis::CrsType::Vertical:
+      case Qgis::CrsType::DerivedProjected:
+        break;
+    }
+
     mVerticalCrs = crs;
     mProjectScope.reset();
 
@@ -1038,6 +1090,7 @@ void QgsProject::setVerticalCrs( const QgsCoordinateReferenceSystem &crs )
     if ( verticalCrs() != oldVerticalCrs )
       emit verticalCrsChanged();
   }
+  return true;
 }
 
 QgsCoordinateTransformContext QgsProject::transformContext() const

src/core/project/qgsproject.h

@@ -423,12 +423,17 @@ class CORE_EXPORT QgsProject : public QObject, public QgsExpressionContextGenera
      * verticalCrs() will be the vertical component of crs(). Otherwise it will be the value
      * explicitly set by this call.
      *
+     * \param crs the vertical CRS
+     * \param errorMessage will be set to a descriptive message if the vertical CRS could not be set
+     *
+     * \returns TRUE if vertical CRS was successfully set
+     *
      * \see verticalCrs()
      * \see setCrs()
      *
      * \since QGIS 3.38
      */
-    void setVerticalCrs( const QgsCoordinateReferenceSystem &crs );
+    bool setVerticalCrs( const QgsCoordinateReferenceSystem &crs, QString *errorMessage SIP_OUT = nullptr );
 
     /**
      * Returns a copy of the project's coordinate transform context, which stores various

tests/src/python/test_qgsproject.py

@@ -164,11 +164,20 @@ def test_vertical_crs(self):
         self.assertFalse(project.verticalCrs().isValid())
 
         spy = QSignalSpy(project.verticalCrsChanged)
-        project.setVerticalCrs(QgsCoordinateReferenceSystem('EPSG:5703'))
+        # not a vertical crs
+        ok, err = project.setVerticalCrs(
+            QgsCoordinateReferenceSystem('EPSG:3111'))
+        self.assertFalse(ok)
+        self.assertEqual(err, 'Specified CRS is a Projected CRS, not a Vertical CRS')
+        self.assertFalse(project.verticalCrs().isValid())
+
+        ok, err = project.setVerticalCrs(QgsCoordinateReferenceSystem('EPSG:5703'))
+        self.assertTrue(ok)
         self.assertEqual(project.verticalCrs().authid(), 'EPSG:5703')
         self.assertEqual(len(spy), 1)
         # try overwriting with same crs, should be no new signal
-        project.setVerticalCrs(QgsCoordinateReferenceSystem('EPSG:5703'))
+        ok, err = project.setVerticalCrs(QgsCoordinateReferenceSystem('EPSG:5703'))
+        self.assertTrue(ok)
         self.assertEqual(len(spy), 1)
 
         # check that project vertical crs variables are set in expression context
@@ -198,6 +207,16 @@ def test_vertical_crs(self):
         self.assertEqual(len(spy), 2)
         self.assertFalse(project.verticalCrs().isValid())
 
+        # test resetting vertical crs back to not set
+        ok, err = project.setVerticalCrs(QgsCoordinateReferenceSystem('EPSG:5703'))
+        self.assertTrue(ok)
+        self.assertEqual(len(spy), 3)
+
+        ok, err = project.setVerticalCrs(QgsCoordinateReferenceSystem())
+        self.assertTrue(ok)
+        self.assertEqual(len(spy), 4)
+        self.assertFalse(project.verticalCrs().isValid())
+
     def test_vertical_crs_with_compound_horizontal_crs(self):
         """
         Test vertical crs logic when project has a compound crs set
@@ -220,15 +239,23 @@ def test_vertical_crs_with_compound_horizontal_crs(self):
         # if we explicitly set a vertical crs now, it should be ignored
         # because the main project crs is a compound crs and that takes
         # precedence
-        project.setVerticalCrs(other_vert_crs)
+        ok, err = project.setVerticalCrs(other_vert_crs)
+        self.assertFalse(ok)
+        self.assertEqual(err, 'Project CRS is a Compound CRS, specified Vertical CRS will be ignored')
+        self.assertEqual(project.verticalCrs().authid(), 'EPSG:5703')
+        self.assertEqual(len(spy), 1)
+        # setting the vertical crs to the vertical component of the compound crs
+        # IS permitted, even though it effectively has no impact...
+        ok, err = project.setVerticalCrs(QgsCoordinateReferenceSystem('EPSG:5703'))
+        self.assertTrue(ok)
         self.assertEqual(project.verticalCrs().authid(), 'EPSG:5703')
         self.assertEqual(len(spy), 1)
 
         # reset horizontal crs to a non-compound crs, now the manually
         # specified vertical crs should take precedence
         project.setCrs(QgsCoordinateReferenceSystem('EPSG:3111'))
-        self.assertEqual(project.verticalCrs().authid(), 'ESRI:115700')
-        self.assertEqual(len(spy), 2)
+        self.assertEqual(project.verticalCrs().authid(), 'EPSG:5703')
+        self.assertEqual(len(spy), 1)
 
     def testEllipsoid(self):
         prj = QgsProject.instance()