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https://issues.apache.org/jira/browse/SPARK-21136?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16304378#comment-16304378
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Denys Zadorozhnyi commented on SPARK-21136:
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I dug up into this issue in Spark 2.2.1 (ANTLR 4.7) and here are my findings:
# 1 The offending token is gathered in {{InputMismatchException}} from
{{recognizer.getCurrentToken()}} (which is "from" in the examples above).
# 2 In ANTLR 4.7.1 in the these cases {{InputMismatchException.offendingState}}
and {{InputMismatchException .ctx}} are additionally set that should give some
clues (see [https://github.com/antlr/antlr4/pull/1969] and the issue
[https://github.com/antlr/antlr4/issues/1922] for details). However the error
message is generated in the ANTLR's {{DefaultErrorStrategy.reportErrror()}}.
I've considered the idea to pass an error handler ({{DefaultErrorStrategy}}
subclass) to the parser and override {{reportError()}}, make a new
{{InputMismatchException}} with "correct" {{offendingToken}} and pass it up the
chain but it did not feel right.
> Misleading error message for typo in SQL
> ----------------------------------------
>
> Key: SPARK-21136
> URL: https://issues.apache.org/jira/browse/SPARK-21136
> Project: Spark
> Issue Type: Bug
> Components: SQL
> Affects Versions: 2.1.0
> Reporter: Daniel Darabos
> Priority: Minor
>
> {code}
> scala> spark.sql("select * from a left joinn b on a.id = b.id").show
> org.apache.spark.sql.catalyst.parser.ParseException:
> mismatched input 'from' expecting {<EOF>, 'WHERE', 'GROUP', 'ORDER',
> 'HAVING', 'LIMIT', 'LATERAL', 'WINDOW', 'UNION', 'EXCEPT', 'MINUS',
> 'INTERSECT', 'SORT', 'CLUSTER', 'DISTRIBUTE'}(line 1, pos 9)
> == SQL ==
> select * from a left joinn b on a.id = b.id
> ---------^^^
> {code}
> The issue is that {{^^^}} points at {{from}}, not at {{joinn}}. The text of
> the error makes no sense either. If {{*}}, {{a}}, and {{b}} are complex in
> themselves, a misleading error like this can hinder debugging substantially.
> I tried to see if maybe I could fix this. Am I correct to deduce that the
> error message originates in ANTLR4, which parses the query based on the
> syntax defined in {{SqlBase.g4}}? If so, I guess I would have to figure out
> how that syntax definition works, and why it misattributes the error.
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