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https://issues.apache.org/jira/browse/CALCITE-5157?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17555141#comment-17555141
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Viliam Durina edited comment on CALCITE-5157 at 6/16/22 3:29 PM:
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{quote}The logic for applying stripAs to the result of stripDot was not clear
after CALCITE-2016 (see commit a3dd90f1) and with this PR is even less clear.
Now we recurse into the same method from two different branches. So, clarify
the logic.
{quote}
This wasn't clear to me as well. I think it's not even possible, I tried to
remove it and all tests passed, so I changed it in the PR. It would apply in
case the operand of the DOT operator was itself wrapped in AS. E.g. {{SELECT
(a.b AS c).d}}, but this won't parse.
{quote}Clean up the stripDot method. Add a brief statement of what it does and
why it exists. If possible remove the 'nullable' annotations from
stripDot{quote}
I added what it does, but I don't myself exactly understand why it exists. I
hoped that [~Chunwei Lei] would enlighten me, or at least confirm that this PR
doesn't break something I'm not aware of.
{quote} Test around this area. Clearly CALCITE-2016 did not nest adequately.
The PR tests only one more query and I suspect this is not adequate.{quote}
I added a couple more tests.
I'd be glad if somebody familiar with the code could review the PR so that it's
released in 1.31.
was (Author: vilo):
{quote}The logic for applying stripAs to the result of stripDot was not clear
after CALCITE-2016 (see commit a3dd90f1) and with this PR is even less clear.
Now we recurse into the same method from two different branches. So, clarify
the logic.
{quote}
This wasn't clear to me as well. I think it's not even possible, I tried to
remove it and all tests passed, so I changed it in the PR. It would apply in
case the operand of the DOT operator was itself wrapped in AS. E.g. {{SELECT
(a.b AS c).d}}, but this won't parse.
{quote}Clean up the stripDot method. Add a brief statement of what it does and
why it exists. If possible remove the 'nullable' annotations from
stripDot{quote}
I added what it does, but I don't myself exactly understand why it exists. I
hoped that [~Chunwei Lei] would enlighten me, or at least confirm that this PR
doesn't break something I'm not aware of.
{quote} Test around this area. Clearly CALCITE-2016 did not nest adequately.
The PR tests only one more query and I suspect this is not adequate.{quote}
I added a couple more tests.
> ClassCastException in checkRollUp with DOT operator
> ---------------------------------------------------
>
> Key: CALCITE-5157
> URL: https://issues.apache.org/jira/browse/CALCITE-5157
> Project: Calcite
> Issue Type: Bug
> Components: core
> Affects Versions: 1.30.0
> Reporter: Viliam Durina
> Priority: Major
> Labels: pull-request-available
> Fix For: 1.31.0
>
> Time Spent: 10m
> Remaining Estimate: 0h
>
> 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:
> {noformat}
> 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
> {noformat}
> The problem can be reproduced by modifying the
> {{ReflectiveSchemaTest.testSelectWithFieldAccessOnFirstLevelRecordType()}}
> test and putting {{au."birthPlace"}} into parentheses:
> {code:sql}
> select (au."birthPlace")."city" as city from ...
> {code}
> 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.
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