[mssql] Fix conversion of time values

At least using the linux sql server driver, time fields are not
correctly automatically converted to QTime variants. Instead
they are returned as a raw byte array containing the value.

Add special handling to ensure that these time values are
read regardless.

(there's already a test in place for this, which was failing
on Linux)

Author: nyalldawson

src/providers/mssql/qgsmssqlfeatureiterator.cpp

@@ -321,10 +321,28 @@ bool QgsMssqlFeatureIterator::fetchFeature( QgsFeature &feature )
 
     for ( int i = 0; i < mAttributesToFetch.count(); i++ )
     {
-      QVariant v = mQuery->value( i );
+      const QVariant originalValue = mQuery->value( i );
       QgsField fld = mSource->mFields.at( mAttributesToFetch.at( i ) );
+      QVariant v = originalValue;
       if ( v.type() != fld.type() )
-        v = QgsVectorDataProvider::convertValue( fld.type(), v.toString() );
+        v = QgsVectorDataProvider::convertValue( fld.type(), originalValue.toString() );
+
+      // second chance for time fields -- time fields are not correctly handled by sql server driver on linux (maybe win too?)
+      if ( v.isNull() && fld.type() == QVariant::Time && originalValue.isValid() && originalValue.type() == QVariant::ByteArray )
+      {
+        // time fields can be returned as byte arrays... woot
+        const QByteArray ba = originalValue.toByteArray();
+        if ( ba.length() >= 5 )
+        {
+          const int hours = ba.at( 0 );
+          const int mins = ba.at( 2 );
+          const int seconds = ba.at( 4 );
+          v = QTime( hours, mins, seconds );
+          if ( !v.isValid() ) // can't handle it
+            v = QVariant( QVariant::Time );
+        }
+      }
+
       feature.setAttribute( mAttributesToFetch.at( i ), v );
     }
 

tests/src/python/test_provider_mssql.py

@@ -74,13 +74,13 @@ def testDateTimeTypes(self):
         f = next(vl.getFeatures(QgsFeatureRequest()))
 
         date_idx = vl.fields().lookupField('date_field')
-        assert isinstance(f.attributes()[date_idx], QDate)
+        self.assertIsInstance(f.attributes()[date_idx], QDate)
         self.assertEqual(f.attributes()[date_idx], QDate(2004, 3, 4))
         time_idx = vl.fields().lookupField('time_field')
-        assert isinstance(f.attributes()[time_idx], QTime)
+        self.assertIsInstance(f.attributes()[time_idx], QTime)
         self.assertEqual(f.attributes()[time_idx], QTime(13, 41, 52))
         datetime_idx = vl.fields().lookupField('datetime_field')
-        assert isinstance(f.attributes()[datetime_idx], QDateTime)
+        self.assertIsInstance(f.attributes()[datetime_idx], QDateTime)
         self.assertEqual(f.attributes()[datetime_idx], QDateTime(
             QDate(2004, 3, 4), QTime(13, 41, 52)))