Avoid losing expression context when accidentally assigning

a context to itself
qgis · Jun 12, 2020 · 8eb1a45 · 8eb1a45
1 parent 24897ab
commit 8eb1a45
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diff --git a/src/core/qgsexpressioncontext.cpp b/src/core/qgsexpressioncontext.cpp
@@ -266,6 +266,9 @@ QgsExpressionContext &QgsExpressionContext::operator=( QgsExpressionContext &&ot
 
 QgsExpressionContext &QgsExpressionContext::operator=( const QgsExpressionContext &other )
 {
+  if ( &other == this )
+    return *this;
+
   qDeleteAll( mStack );
   mStack.clear();
   for ( const QgsExpressionContextScope *scope : qgis::as_const( other.mStack ) )

diff --git a/src/core/qgsfeaturerequest.cpp b/src/core/qgsfeaturerequest.cpp
@@ -63,6 +63,9 @@ QgsFeatureRequest::QgsFeatureRequest( const QgsFeatureRequest &rh )
 
 QgsFeatureRequest &QgsFeatureRequest::operator=( const QgsFeatureRequest &rh )
 {
+  if ( &rh == this )
+    return *this;
+
   mFlags = rh.mFlags;
   mFilter = rh.mFilter;
   mFilterRect = rh.mFilterRect;

diff --git a/tests/src/python/CMakeLists.txt b/tests/src/python/CMakeLists.txt
@@ -76,6 +76,7 @@ ADD_PYTHON_TEST(PyQgsProjectDisplaySettings test_qgsprojectdisplaysettings.py)
 ADD_PYTHON_TEST(PyQgsProjectTimeSettings test_qgsprojecttimesettings.py)
 ADD_PYTHON_TEST(PyQgsProjectViewSettings test_qgsprojectviewsettings.py)
 ADD_PYTHON_TEST(PyQgsFeatureIterator test_qgsfeatureiterator.py)
+ADD_PYTHON_TEST(PyQgsFeatureRequest test_qgsfeaturerequest.py)
 ADD_PYTHON_TEST(PyQgsFeedback test_qgsfeedback.py)
 ADD_PYTHON_TEST(PyQgsFields test_qgsfields.py)
 ADD_PYTHON_TEST(PyQgsFieldModel test_qgsfieldmodel.py)

diff --git a/tests/src/python/test_qgsfeaturerequest.py b/tests/src/python/test_qgsfeaturerequest.py
@@ -0,0 +1,253 @@
+# -*- coding: utf-8 -*-
+"""QGIS Unit tests for QgsFeatureRequest.
+
+.. note:: This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+"""
+__author__ = 'Nyall Dawson'
+__date__ = '12/06/2020'
+__copyright__ = 'Copyright 2020, The QGIS Project'
+
+import qgis  # NOQA
+
+from qgis.core import (QgsFeatureRequest,
+                       QgsRectangle,
+                       QgsExpressionContext,
+                       QgsExpressionContextScope,
+                       QgsFields,
+                       QgsField,
+                       QgsSimplifyMethod,
+                       QgsCoordinateReferenceSystem,
+                       QgsCoordinateTransformContext)
+from qgis.PyQt.QtCore import QVariant
+from qgis.testing import start_app, unittest
+
+
+from utilities import unitTestDataPath
+
+start_app()
+TEST_DATA_DIR = unitTestDataPath()
+
+
+class TestQgsFeatureRequest(unittest.TestCase):
+
+    def __init__(self, methodName):
+        """Run once on class initialization."""
+        unittest.TestCase.__init__(self, methodName)
+
+    def testConstructors(self):
+        req = QgsFeatureRequest()
+        self.assertEqual(req.filterType(), QgsFeatureRequest.FilterNone)
+        self.assertEqual(req.filterFid(), -1)
+        self.assertFalse(req.filterFids())
+
+        req = QgsFeatureRequest(55)
+        self.assertEqual(req.filterType(), QgsFeatureRequest.FilterFid)
+        self.assertEqual(req.filterFid(), 55)
+        self.assertFalse(req.filterFids())
+
+        req = QgsFeatureRequest([55, 56])
+        self.assertEqual(req.filterType(), QgsFeatureRequest.FilterFids)
+        self.assertEqual(req.filterFid(), -1)
+        self.assertCountEqual(req.filterFids(), [55, 56])
+
+    def testFilterRect(self):
+        req = QgsFeatureRequest().setFilterRect(QgsRectangle(1, 2, 3, 4))
+        self.assertEqual(req.filterFid(), -1)
+        self.assertFalse(req.filterFids())
+        self.assertEqual(req.filterRect(), QgsRectangle(1, 2, 3, 4))
+
+    def testFilterFid(self):
+        req = QgsFeatureRequest().setFilterFid(5)
+        self.assertEqual(req.filterType(), QgsFeatureRequest.FilterFid)
+        self.assertEqual(req.filterFid(), 5)
+        self.assertFalse(req.filterFids())
+
+        # filter rect doesn't affect fid filter
+        req.setFilterRect(QgsRectangle(1, 2, 3, 4))
+        self.assertEqual(req.filterType(), QgsFeatureRequest.FilterFid)
+        self.assertEqual(req.filterFid(), 5)
+        self.assertEqual(req.filterRect(), QgsRectangle(1, 2, 3, 4))
+        req.setFilterFid(6)
+        self.assertEqual(req.filterType(), QgsFeatureRequest.FilterFid)
+        self.assertEqual(req.filterFid(), 6)
+        self.assertEqual(req.filterRect(), QgsRectangle(1, 2, 3, 4))
+
+    def testFilterFids(self):
+        req = QgsFeatureRequest().setFilterFids([5, 6])
+        self.assertEqual(req.filterType(), QgsFeatureRequest.FilterFids)
+        self.assertEqual(req.filterFid(), -1)
+        self.assertCountEqual(req.filterFids(), [5, 6])
+
+        # filter rect doesn't affect fids filter
+        req.setFilterRect(QgsRectangle(1, 2, 3, 4))
+        self.assertEqual(req.filterType(), QgsFeatureRequest.FilterFids)
+        self.assertEqual(req.filterFid(), -1)
+        self.assertCountEqual(req.filterFids(), [5, 6])
+        req.setFilterFids([8, 9])
+        self.assertEqual(req.filterType(), QgsFeatureRequest.FilterFids)
+        self.assertEqual(req.filterFid(), -1)
+        self.assertCountEqual(req.filterFids(), [8, 9])
+        self.assertEqual(req.filterRect(), QgsRectangle(1, 2, 3, 4))
+
+    def testInvalidGeomCheck(self):
+        req = QgsFeatureRequest().setFilterFids([5, 6]).setInvalidGeometryCheck(QgsFeatureRequest.GeometrySkipInvalid)
+        self.assertEqual(req.filterType(), QgsFeatureRequest.FilterFids)
+        self.assertEqual(req.filterFid(), -1)
+        self.assertCountEqual(req.filterFids(), [5, 6])
+        self.assertEqual(req.invalidGeometryCheck(), QgsFeatureRequest.GeometrySkipInvalid)
+        req.setInvalidGeometryCheck(QgsFeatureRequest.GeometryNoCheck)
+        self.assertEqual(req.invalidGeometryCheck(), QgsFeatureRequest.GeometryNoCheck)
+
+    def testFilterExpression(self):
+        req = QgsFeatureRequest().setFilterExpression('a=5')
+        self.assertEqual(req.filterType(), QgsFeatureRequest.FilterExpression)
+        self.assertEqual(req.filterFid(), -1)
+        self.assertFalse(req.filterFids())
+        self.assertEqual(req.filterExpression().expression(), 'a=5')
+
+        # filter rect doesn't affect fids filter
+        req.setFilterRect(QgsRectangle(1, 2, 3, 4))
+        self.assertEqual(req.filterFid(), -1)
+        self.assertFalse(req.filterFids())
+        self.assertEqual(req.filterExpression().expression(), 'a=5')
+        req.setFilterExpression('a=8')
+        self.assertEqual(req.filterFid(), -1)
+        self.assertFalse(req.filterFids())
+        self.assertEqual(req.filterExpression().expression(), 'a=8')
+        self.assertEqual(req.filterRect(), QgsRectangle(1, 2, 3, 4))
+
+    def testCombineFilter(self):
+        req = QgsFeatureRequest()
+        req.combineFilterExpression('b=9')
+        self.assertEqual(req.filterType(), QgsFeatureRequest.FilterExpression)
+        self.assertEqual(req.filterFid(), -1)
+        self.assertFalse(req.filterFids())
+        self.assertEqual(req.filterExpression().expression(), 'b=9')
+
+        req.combineFilterExpression('a=11')
+        self.assertEqual(req.filterExpression().expression(), '(b=9) AND (a=11)')
+
+    def testExpressionContext(self):
+        req = QgsFeatureRequest()
+        self.assertEqual(req.expressionContext().scopeCount(), 0)
+
+        context = QgsExpressionContext()
+        scope = QgsExpressionContextScope()
+        scope.setVariable('a', 6)
+        context.appendScope(scope)
+        req.setExpressionContext(context)
+
+        self.assertEqual(req.expressionContext().scopeCount(), 1)
+        self.assertEqual(req.expressionContext().variable('a'), 6)
+
+    def testDisableFilter(self):
+        req = QgsFeatureRequest().setFilterFid(5).disableFilter()
+        self.assertEqual(req.filterType(), QgsFeatureRequest.FilterNone)
+
+        req = QgsFeatureRequest().setFilterFids([5, 6]).disableFilter()
+        self.assertEqual(req.filterType(), QgsFeatureRequest.FilterNone)
+
+        req = QgsFeatureRequest().setFilterExpression('a=5').disableFilter()
+        self.assertEqual(req.filterType(), QgsFeatureRequest.FilterNone)
+        self.assertFalse(req.filterExpression())
+
+    def testLimit(self):
+        req = QgsFeatureRequest()
+        self.assertEqual(req.limit(), -1)
+        req.setLimit(6)
+        self.assertEqual(req.limit(), 6)
+
+    def testFlags(self):
+        req = QgsFeatureRequest()
+        self.assertFalse(req.flags())
+        req.setFlags(QgsFeatureRequest.ExactIntersect)
+        self.assertEqual(req.flags(), QgsFeatureRequest.ExactIntersect)
+
+    def testSubsetAttributes(self):
+        req = QgsFeatureRequest()
+        self.assertFalse(req.subsetOfAttributes())
+        self.assertFalse(req.flags() & QgsFeatureRequest.SubsetOfAttributes)
+
+        req.setSubsetOfAttributes([1, 4])
+        self.assertEqual(req.subsetOfAttributes(), [1, 4])
+        self.assertTrue(req.flags() & QgsFeatureRequest.SubsetOfAttributes)
+
+        req.setNoAttributes()
+        self.assertEqual(req.subsetOfAttributes(), [])
+        self.assertTrue(req.flags() & QgsFeatureRequest.SubsetOfAttributes)
+
+        req.setSubsetOfAttributes([])
+        self.assertFalse(req.subsetOfAttributes())
+        self.assertTrue(req.flags() & QgsFeatureRequest.SubsetOfAttributes)
+
+        req.setFlags(QgsFeatureRequest.Flags())
+        f = QgsFields()
+        f.append(QgsField('a', QVariant.String))
+        f.append(QgsField('b', QVariant.String))
+        f.append(QgsField('c', QVariant.String))
+        req.setSubsetOfAttributes(['a', 'c'], f)
+        self.assertEqual(req.subsetOfAttributes(), [0, 2])
+        self.assertTrue(req.flags() & QgsFeatureRequest.SubsetOfAttributes)
+
+    def testSimplifyMethod(self):
+        req = QgsFeatureRequest()
+        self.assertEqual(req.simplifyMethod().methodType(), QgsSimplifyMethod.NoSimplification)
+        method = QgsSimplifyMethod()
+        method.setMethodType(QgsSimplifyMethod.PreserveTopology)
+        req.setSimplifyMethod(method)
+        self.assertEqual(req.simplifyMethod().methodType(), QgsSimplifyMethod.PreserveTopology)
+
+    def testDestinationCrs(self):
+        req = QgsFeatureRequest()
+        self.assertFalse(req.destinationCrs().isValid())
+        context = QgsCoordinateTransformContext()
+        req.setDestinationCrs(QgsCoordinateReferenceSystem('EPSG:3857'), context)
+        self.assertTrue(req.destinationCrs().isValid())
+        self.assertEqual(req.destinationCrs().authid(), 'EPSG:3857')
+
+    def testTimeout(self):
+        req = QgsFeatureRequest()
+        self.assertEqual(req.timeout(), -1)
+        req.setTimeout(6)
+        self.assertEqual(req.timeout(), 6)
+
+    def testNested(self):
+        req = QgsFeatureRequest()
+        self.assertFalse(req.requestMayBeNested())
+        req.setRequestMayBeNested(True)
+        self.assertTrue(req.requestMayBeNested())
+
+    def testAssignment(self):
+        req = QgsFeatureRequest().setFilterFids([8, 9]).setFilterRect(QgsRectangle(1, 2, 3, 4)).setInvalidGeometryCheck(QgsFeatureRequest.GeometrySkipInvalid).setLimit(6).setFlags(QgsFeatureRequest.ExactIntersect).setSubsetOfAttributes([1, 4]).setTimeout(6).setRequestMayBeNested(True)
+
+        context = QgsExpressionContext()
+        scope = QgsExpressionContextScope()
+        scope.setVariable('a', 6)
+        context.appendScope(scope)
+        req.setExpressionContext(context)
+        method = QgsSimplifyMethod()
+        method.setMethodType(QgsSimplifyMethod.PreserveTopology)
+        req.setSimplifyMethod(method)
+        context = QgsCoordinateTransformContext()
+        req.setDestinationCrs(QgsCoordinateReferenceSystem('EPSG:3857'), context)
+
+        req2 = QgsFeatureRequest(req)
+        self.assertEqual(req2.limit(), 6)
+        self.assertCountEqual(req2.filterFids(), [8, 9])
+        self.assertEqual(req2.filterRect(), QgsRectangle(1, 2, 3, 4))
+        self.assertEqual(req2.invalidGeometryCheck(), QgsFeatureRequest.GeometrySkipInvalid)
+        self.assertEqual(req2.expressionContext().scopeCount(), 1)
+        self.assertEqual(req2.expressionContext().variable('a'), 6)
+        self.assertEqual(req2.flags(), QgsFeatureRequest.ExactIntersect | QgsFeatureRequest.SubsetOfAttributes)
+        self.assertEqual(req2.subsetOfAttributes(), [1, 4])
+        self.assertEqual(req2.simplifyMethod().methodType(), QgsSimplifyMethod.PreserveTopology)
+        self.assertEqual(req2.destinationCrs().authid(), 'EPSG:3857')
+        self.assertEqual(req2.timeout(), 6)
+        self.assertTrue(req2.requestMayBeNested())
+
+
+if __name__ == '__main__':
+    unittest.main()