Fix storing string representations of doubles in an int field

nyalldawson · nyalldawson · commit 1c76b93d89e9 · 2015-10-20T20:36:07.000+11:00
results in NULL rather than converting value to int
diff --git a/src/core/qgsfield.cpp b/src/core/qgsfield.cpp
@@ -16,6 +16,7 @@
 
 #include "qgsfield.h"
 #include "qgsfield_p.h"
+#include "qgis.h"
 
 #include <QSettings>
 #include <QDataStream>
@@ -155,6 +156,30 @@ bool QgsField::convertCompatible( QVariant& v ) const
     return false;
   }
 
+  //String representations of doubles in QVariant will return false to convert( QVariant::Int )
+  //work around this by first converting to double, and then checking whether the double is convertible to int
+  if ( d->type == QVariant::Int && v.canConvert( QVariant::Double ) )
+  {
+    bool ok = false;
+    double dbl = v.toDouble( &ok );
+    if ( !ok )
+    {
+      //couldn't convert to number
+      v = QVariant( d->type );
+      return false;
+    }
+
+    double round = qgsRound( dbl );
+    if ( round  > INT_MAX || round < -INT_MAX )
+    {
+      //double too large to fit in int
+      v = QVariant( d->type );
+      return false;
+    }
+    v = QVariant( qRound( dbl ) );
+    return true;
+  }
+
   if ( !v.convert( d->type ) )
   {
     v = QVariant( d->type );
diff --git a/tests/src/core/testqgsfield.cpp b/tests/src/core/testqgsfield.cpp
@@ -256,12 +256,52 @@ void TestQgsField::convertCompatible()
 
   //test special rules
 
-  //conversion of longlong to int
+  //conversion of double to int
   QgsField intField( "int", QVariant::Int, "int" );
+  //small double, should be rounded
+  QVariant smallDouble( 45.7 );
+  QVERIFY( intField.convertCompatible( smallDouble ) );
+  QCOMPARE( smallDouble.type(), QVariant::Int );
+  QCOMPARE( smallDouble, QVariant( 46 ) );
+  QVariant negativeSmallDouble( -9345.754534525235235 );
+  QVERIFY( intField.convertCompatible( negativeSmallDouble ) );
+  QCOMPARE( negativeSmallDouble.type(), QVariant::Int );
+  QCOMPARE( negativeSmallDouble, QVariant( -9346 ) );
+  //large double, cannot be converted
+  QVariant largeDouble( 9999999999.99 );
+  QVERIFY( !intField.convertCompatible( largeDouble ) );
+  QCOMPARE( largeDouble.type(), QVariant::Int );
+  QVERIFY( largeDouble.isNull( ) );
+
+  //conversion of string double value to int
+  QVariant notNumberString( "notanumber" );
+  QVERIFY( !intField.convertCompatible( notNumberString ) );
+  QCOMPARE( notNumberString.type(), QVariant::Int );
+  QVERIFY( notNumberString.isNull( ) );
+  //small double, should be rounded
+  QVariant smallDoubleString( "45.7" );
+  QVERIFY( intField.convertCompatible( smallDoubleString ) );
+  QCOMPARE( smallDoubleString.type(), QVariant::Int );
+  QCOMPARE( smallDoubleString, QVariant( 46 ) );
+  QVariant negativeSmallDoubleString( "-9345.754534525235235" );
+  QVERIFY( intField.convertCompatible( negativeSmallDoubleString ) );
+  QCOMPARE( negativeSmallDoubleString.type(), QVariant::Int );
+  QCOMPARE( negativeSmallDoubleString, QVariant( -9346 ) );
+  //large double, cannot be converted
+  QVariant largeDoubleString( "9999999999.99" );
+  QVERIFY( !intField.convertCompatible( largeDoubleString ) );
+  QCOMPARE( largeDoubleString.type(), QVariant::Int );
+  QVERIFY( largeDoubleString.isNull( ) );
+
+  //conversion of longlong to int
   QVariant longlong( 99999999999999999LL );
   QVERIFY( !intField.convertCompatible( longlong ) );
   QCOMPARE( longlong.type(), QVariant::Int );
   QVERIFY( longlong.isNull( ) );
+  QVariant smallLonglong( 99LL );
+  QVERIFY( intField.convertCompatible( smallLonglong ) );
+  QCOMPARE( smallLonglong.type(), QVariant::Int );
+  QCOMPARE( smallLonglong, QVariant( 99 ) );
   //conversion of longlong to longlong field
   QgsField longlongField( "long", QVariant::LongLong, "longlong" );
   longlong = QVariant( 99999999999999999LL );
