[CALCITE-5157] Query that applies dot operator (field access) to parenthesized expression throws ClassCastException

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.30.0
• Fix Version/s: 1.31.0
• Component/s: core
• Labels: pull-request-available
• Assignee: Unassigned
• Reporter: Viliam Durina
• Created: 17/May/22 17:48
• Updated: 03/Aug/22 16:21
• Resolved: 21/Jun/22 06:50

Description

When a query contains nested field access and is using parentheses to disambiguate the identifier, the SqlValidatorImpl.checkRollup() method throws a ClassCastException, assuming that the input of the DOT operator is a SqlCall. I think this assumption is wrong, the DOT operator typically has SqlIdentifier as an input, probably also other classes.

Here's the stack trace:

java.lang.ClassCastException: class org.apache.calcite.sql.SqlIdentifier cannot be cast to class org.apache.calcite.sql.SqlCall (org.apache.calcite.sql.SqlIdentifier and org.apache.calcite.sql.SqlCall are in unnamed module of loader 'app')
    at org.apache.calcite.sql.validate.SqlValidatorImpl.checkRollUp(SqlValidatorImpl.java:3730)
    at org.apache.calcite.sql.validate.SqlValidatorImpl.checkRollUp(SqlValidatorImpl.java:3749)
    at org.apache.calcite.sql.validate.SqlValidatorImpl.checkRollUpInSelectList(SqlValidatorImpl.java:3673)
    at org.apache.calcite.sql.validate.SqlValidatorImpl.validateSelect(SqlValidatorImpl.java:3661)
    at org.apache.calcite.sql.validate.SelectNamespace.validateImpl(SelectNamespace.java:64)
    at org.apache.calcite.sql.validate.AbstractNamespace.validate(AbstractNamespace.java:89)
    at org.apache.calcite.sql.validate.SqlValidatorImpl.validateNamespace(SqlValidatorImpl.java:1100)
    at org.apache.calcite.sql.validate.SqlValidatorImpl.validateQuery(SqlValidatorImpl.java:1071)
    at org.apache.calcite.sql.SqlSelect.validate(SqlSelect.java:247)
    at org.apache.calcite.sql.validate.SqlValidatorImpl.validateScopedExpression(SqlValidatorImpl.java:1046)
    at org.apache.calcite.sql.validate.SqlValidatorImpl.validate(SqlValidatorImpl.java:752)
    at org.apache.calcite.sql2rel.SqlToRelConverter.convertQuery(SqlToRelConverter.java:587)
    at org.apache.calcite.prepare.Prepare.prepareSql(Prepare.java:257)
    at org.apache.calcite.prepare.Prepare.prepareSql(Prepare.java:220)
    at org.apache.calcite.prepare.CalcitePrepareImpl.prepare2_(CalcitePrepareImpl.java:648)
    at org.apache.calcite.prepare.CalcitePrepareImpl.prepare_(CalcitePrepareImpl.java:514)
    at org.apache.calcite.prepare.CalcitePrepareImpl.prepareSql(CalcitePrepareImpl.java:484)
    at org.apache.calcite.jdbc.CalciteConnectionImpl.parseQuery(CalciteConnectionImpl.java:234)
    at org.apache.calcite.jdbc.CalciteMetaImpl.prepareAndExecute(CalciteMetaImpl.java:623)
    at org.apache.calcite.avatica.AvaticaConnection.prepareAndExecuteInternal(AvaticaConnection.java:677)
    at org.apache.calcite.avatica.AvaticaStatement.executeInternal(AvaticaStatement.java:156)
    ... 67 more

The problem can be reproduced by modifying the ReflectiveSchemaTest.testSelectWithFieldAccessOnFirstLevelRecordType() test and putting au."birthPlace" into parentheses:

select (au."birthPlace")."city" as city from ... 

Putting identifiers into parentheses is common to disambiguate field access from identifier qualification. For example, if the au prefix is removed from the query in the testSelectWithFieldAccessOnFirstLevelRecordType test, it will fail with Table 'birthPlace' not found. But if we put \"birthPlace\" into parentheses, then it is correctly recognized as a column of the authors table.

I'm not sure about the correct fix to this issue which would not break the roll-up functionality, perhaps its author zhumayun can help reviewing the PR or suggesting another fix. I'll soon create a PR with a proposed fix.

Issue Links

• is related to: CALCITE-2016 ITEM + DOT operator does not work for array
• links to: GitHub Pull Request #2808