[CALCITE-6877] Generate LogicalProject in RelRoot.project() when mapping is not name trivial

[nielspardon]

See https://issues.apache.org/jira/browse/CALCITE-6877

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[mihaibudiu]

Interesting that this does not affect any existing tests.

[nielspardon]

Interesting that this does not affect any existing tests.

Indeed, I was also a bit suprised that this code has been there for 9 years and nobody has encountered this before.

One thing I found was that when you start with a SQL statement through the SQL parser it combines the column reduction and renaming into a single LogicalProject which ends up within the RelRoot.rel so through the normal test approach in e.g. SqlToRelConverterTest you will not encounter this scenario.