Created attachment 910870 [details]
Maven based test

Description of problem:
For any simple entity (e.g. Event) a native SQL query which specifies a column multiple times (e.g. "select e.id, e.title, e.id from Event e") fails in Hibernate 4:

org.hibernate.loader.custom.NonUniqueDiscoveredSqlAliasException: Encountered a duplicated sql alias [id] during auto-discovery of a native-sql query

Version-Release number of selected component (if applicable):
Hibernate 4

How reproducible:
Consistently

Steps to Reproduce:
For a simple entity, execute a native SQL query specifying one column (e.g. 'id') multiple times
	List results = session.createSQLQuery(
		"select e.id, e.title, e.id from Event e").list();

Actual results:
org.hibernate.loader.custom.NonUniqueDiscoveredSqlAliasException: Encountered a duplicated sql alias [id] during auto-discovery of a native-sql query
	at org.hibernate.loader.custom.CustomLoader.autoDiscoverTypes(CustomLoader.java:630)
	at org.hibernate.loader.Loader.getResultSet(Loader.java:2039)
	at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1832)
	at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1811)
	at org.hibernate.loader.Loader.doQuery(Loader.java:899)
	at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:341)
	at org.hibernate.loader.Loader.doList(Loader.java:2516)
	at org.hibernate.loader.Loader.doList(Loader.java:2502)
	at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2332)
	at org.hibernate.loader.Loader.list(Loader.java:2327)
	at org.hibernate.loader.custom.CustomLoader.list(CustomLoader.java:338)
	at org.hibernate.internal.SessionImpl.listCustomQuery(SessionImpl.java:1826)
	at org.hibernate.internal.AbstractSessionImpl.list(AbstractSessionImpl.java:231)
	at org.hibernate.internal.SQLQueryImpl.list(SQLQueryImpl.java:157)
	...

Expected results:
The exception is not expected.

Additional info:
- The same query works as late as in Hibernate 3.3.2.GA.
- Modifying the query to use explicit column aliases works around the issue:
	"select e.id as eid1, e.title, e.id as eid2 from Event e"