Api dox for QContactSaveRequest::setDefinitionMask(QStringList) says: "This allows you to perform partial save (and remove) operations on existing contacts."
http://doc.qt.nokia.com/qtmobility-1.2/qcontactsaverequest.html#setDefinitionMask
And the API dox for QContactManager::saveContacts(QList<QContact> *, QStringList, QMap<int, QContactManager::Error> *) says: "This function accepts a definitionMask, which specifies which details of the contacts should be updated."
http://doc.qt.nokia.com/qtmobility-1.2/qcontactmanager.html#saveContacts-2

But the unit test tst_QContactManager::partialSave() seems to assume that even with a detail mask new contacts can be stored: "QVERIFY(contacts[5].localId() != 0); // Saved"
https://www.qt.gitorious.org/qt-mobility/contacts/blobs/48c5131/tests/auto/qcontactmanager/tst_qcontactmanager.cpp#line3898 ff.

Please either fix the unit test, or make the API dox mention that also new contacts can be stored. qtcontacts-tracker so far was to implement on support for updating existing contacts, until this unit test showed some different expectations.

I may see the usecase for also allowing to also save new contacts with a mask, e.g. the mentioned synchronizing with a different backend. But the API dox must be clear about what to expect, please.