Bugfix: Escape Column Name in Generated Spark SQL #85
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sscdotopen
approved these changes
Feb 1, 2019
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Issue #, if available:
#84
Description of changes:
This PR properly escapes column names in generated Spark SQL code.
Currently, when executing a
isContainedInCheckon anyDataFramethat contains any column whose name contains any characters that make up any reserved keyword in Spark SQL will cause a runtime failure. Digging into it, the runtime failure will show the root cause is a Spark SQL syntax error (specifically aorg.apache.spark.sql.catalyst.parser.ParseException) due to incorrectly parsing the column name.E.g. if the column name starts with
[, then the exception will read as:The fix for this bug is to wrap all bare column names in generated Spark SQL with backticks: ``. I.e. a query such as
$column IS NULLis unsafe, but it's escaped variant is ok to execute, regardless of the value of$column:A new test showcasing this functionality is in the
CheckTestclassnamed"Check on column names with special characters". This test executes theisContainedInCheckon both a value list as well as a (minimum, maximum) boundary. It succeeds only when the associated generated Spark SQL code has the escaped column name.By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.