[processing] Catch transform errors in when iterating features

Author: nyalldawson

python/core/processing/qgsprocessingcontext.sip

@@ -163,6 +163,28 @@ Destination project
 %End
 
 
+    void setTransformErrorCallback( SIP_PYCALLABLE / AllowNone / );
+%Docstring
+ Sets a callback function to use when encountering a transform error when iterating
+ features. This function will be
+ called using the feature which encountered the transform error as a parameter.
+.. versionadded:: 3.0
+.. seealso:: transformErrorCallback()
+%End
+%MethodCode
+    Py_BEGIN_ALLOW_THREADS
+
+    sipCpp->setTransformErrorCallback( [a0]( const QgsFeature &arg )
+    {
+      SIP_BLOCK_THREADS
+      Py_XDECREF( sipCallMethod( NULL, a0, "D", &arg, sipType_QgsFeature, NULL ) );
+      SIP_UNBLOCK_THREADS
+    } );
+
+    Py_END_ALLOW_THREADS
+%End
+
+
     QString defaultEncoding() const;
 %Docstring
  Returns the default encoding to use for newly created files.

python/plugins/processing/tools/dataobjects.py

@@ -85,6 +85,11 @@ def raise_error(f):
 
     context.setInvalidGeometryCallback(raise_error)
 
+    def raise_transform_error(f):
+        raise GeoAlgorithmExecutionException(QCoreApplication.translate("FeatureIterator",
+                                                                        'Encountered a transform error when reprojecting feature with id {}.'.format(f.id())))
+    context.setTransformErrorCallback(raise_transform_error)
+
     settings = QgsSettings()
     context.setDefaultEncoding(settings.value("/Processing/encoding", "System"))
 

src/core/processing/qgsprocessingcontext.h

@@ -206,6 +206,41 @@ class CORE_EXPORT QgsProcessingContext
      */
     SIP_SKIP std::function< void( const QgsFeature & ) > invalidGeometryCallback() const { return mInvalidGeometryCallback; }
 
+    /**
+     * Sets a callback function to use when encountering a transform error when iterating
+     * features. This function will be
+     * called using the feature which encountered the transform error as a parameter.
+     * \since QGIS 3.0
+     * \see transformErrorCallback()
+     */
+#ifndef SIP_RUN
+    void setTransformErrorCallback( std::function< void( const QgsFeature & ) > callback ) { mTransformErrorCallback = callback; }
+#else
+    void setTransformErrorCallback( SIP_PYCALLABLE / AllowNone / );
+    % MethodCode
+    Py_BEGIN_ALLOW_THREADS
+
+    sipCpp->setTransformErrorCallback( [a0]( const QgsFeature &arg )
+    {
+      SIP_BLOCK_THREADS
+      Py_XDECREF( sipCallMethod( NULL, a0, "D", &arg, sipType_QgsFeature, NULL ) );
+      SIP_UNBLOCK_THREADS
+    } );
+
+    Py_END_ALLOW_THREADS
+    % End
+#endif
+
+    /**
+     * Returns the callback function to use when encountering a transform error when iterating
+     * features.
+     * \since QGIS 3.0
+     * \note not available in Python bindings
+     * \see setTransformErrorCallback()
+     * \see destinationCrs()
+     */
+    std::function< void( const QgsFeature & ) > transformErrorCallback() const { return mTransformErrorCallback; } SIP_SKIP
+
     /**
      * Returns the default encoding to use for newly created files.
      * \see setDefaultEncoding()
@@ -228,6 +263,7 @@ class CORE_EXPORT QgsProcessingContext
     QgsExpressionContext mExpressionContext;
     QgsFeatureRequest::InvalidGeometryCheck mInvalidGeometryCheck = QgsFeatureRequest::GeometryNoCheck;
     std::function< void( const QgsFeature & ) > mInvalidGeometryCallback;
+    std::function< void( const QgsFeature & ) > mTransformErrorCallback;
     QString mDefaultEncoding;
     QMap< QString, LayerDetails > mLayersToLoadOnCompletion;
 

src/core/processing/qgsprocessingutils.cpp

@@ -375,6 +375,7 @@ QgsProcessingFeatureSource::QgsProcessingFeatureSource( QgsFeatureSource *origin
   , mOwnsSource( ownsOriginalSource )
   , mInvalidGeometryCheck( context.invalidGeometryCheck() )
   , mInvalidGeometryCallback( context.invalidGeometryCallback() )
+  , mTransformErrorCallback( context.transformErrorCallback() )
 {}
 
 QgsProcessingFeatureSource::~QgsProcessingFeatureSource()
@@ -388,6 +389,7 @@ QgsFeatureIterator QgsProcessingFeatureSource::getFeatures( const QgsFeatureRequ
   QgsFeatureRequest req( request );
   req.setInvalidGeometryCheck( mInvalidGeometryCheck );
   req.setInvalidGeometryCallback( mInvalidGeometryCallback );
+  req.setTransformErrorCallback( mTransformErrorCallback );
   return mSource->getFeatures( req );
 }
 

src/core/processing/qgsprocessingutils.h

@@ -228,6 +228,7 @@ class QgsProcessingFeatureSource : public QgsFeatureSource
     bool mOwnsSource = false;
     QgsFeatureRequest::InvalidGeometryCheck mInvalidGeometryCheck = QgsFeatureRequest::GeometryNoCheck;
     std::function< void( const QgsFeature & ) > mInvalidGeometryCallback;
+    std::function< void( const QgsFeature & ) > mTransformErrorCallback;
 
 };