From 30449e577f0cd432bd8c60787743fba54c1e51b9 Mon Sep 17 00:00:00 2001
From: Nyall Dawson <nyall.dawson@gmail.com>
Date: Thu, 3 Mar 2016 10:34:32 +1100
Subject: [PATCH] Fix fetching subset of attributes with mssql (fix #14402),
 add test

---
 src/providers/mssql/qgsmssqlfeatureiterator.cpp |  2 +-
 tests/src/python/providertestbase.py            | 11 +++++++++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/providers/mssql/qgsmssqlfeatureiterator.cpp b/src/providers/mssql/qgsmssqlfeatureiterator.cpp
index 53214d4..560d344 100644
--- a/src/providers/mssql/qgsmssqlfeatureiterator.cpp
+++ b/src/providers/mssql/qgsmssqlfeatureiterator.cpp
@@ -284,7 +284,7 @@ bool QgsMssqlFeatureIterator::fetchFeature( QgsFeature& feature )
     for ( int i = 0; i < mAttributesToFetch.count(); i++ )
     {
       QVariant v = mQuery->value( i );
-      const QgsField &fld = mSource->mFields.at( i );
+      const QgsField &fld = mSource->mFields.at( mAttributesToFetch.at( i ) );
       if ( v.type() != fld.type() )
         v = QgsVectorDataProvider::convertValue( fld.type(), v.toString() );
       feature.setAttribute( mAttributesToFetch.at( i ), v );
diff --git a/tests/src/python/providertestbase.py b/tests/src/python/providertestbase.py
index 7b8707e..26e6d86 100644
--- a/tests/src/python/providertestbase.py
+++ b/tests/src/python/providertestbase.py
@@ -384,3 +384,14 @@ def testClosedIterators(self):
 
         # Test rewinding closed iterator
         self.assertFalse(f_it.rewind(), 'Rewinding closed iterator successful, should not be allowed')
+
+    def testGetFeaturesSubsetAttributes(self):
+        """ Test that expected results are returned when using subsets of attributes """
+
+        tests = {'pk': set([1, 2, 3, 4, 5]),
+                 'cnt': set([-200, 300, 100, 200, 400]),
+                 'name': set(['Pear', 'Orange', 'Apple', 'Honey', NULL]),
+                 'name2': set(['NuLl', 'PEaR', 'oranGe', 'Apple', 'Honey'])}
+        for field, expected in tests.iteritems():
+            result = set([f[field] for f in self.provider.getFeatures(QgsFeatureRequest().setSubsetOfAttributes([field], self.provider.fields()))])
+            self.assertEqual(result, expected, 'Expected {}, got {}'.format(expected, result))