[
https://issues.apache.org/jira/browse/METRON-1877?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16689635#comment-16689635
]
ASF GitHub Bot commented on METRON-1877:
----------------------------------------
GitHub user justinleet opened a pull request:
https://github.com/apache/metron/pull/1268
METRON-1877: Nested IF ELSE statements can cause parse errors in Stellar
## Contributor Comments
When we're dealing with if-else, the existing code would simply say we need
to skip an else. In the case of nested if-else, the outer else would say to
skip the inner else and cause issues. By tracking the number of else's to
skip, we can manage the nesting properly.
Short-circuiting also needed updating, because it was also experiencing a
similar issue.
A variety of unit tests has been added to address both of these, and ensure
slightly more complicated nestings are tested.
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You can merge this pull request into a Git repository by running:
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Alternatively you can review and apply these changes as the patch at:
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This closes #1268
----
commit cb5911b149c111eb618593503083d26d09f17139
Author: justinjleet <justinjleet@...>
Date: 2018-11-16T16:26:14Z
Expanding handling of Stellar if-else to avoid mismatching if to an else
----
> Nested IF ELSE statements can cause parse errors in Stellar
> -----------------------------------------------------------
>
> Key: METRON-1877
> URL: https://issues.apache.org/jira/browse/METRON-1877
> Project: Metron
> Issue Type: Improvement
> Reporter: Justin Leet
> Assignee: Justin Leet
> Priority: Major
>
> IF ELSE statements nested inside IF ELSEstatements can cause problems with
> short-circuiting. See the following example.
> {code:java}
> Stellar>>> IF true THEN IF false THEN true ELSE false ELSE is_alert
> false
> Stellar>>> IF true THEN IF true THEN true ELSE false ELSE is_alert
> ! Invalid parse, found null
> org.apache.metron.stellar.dsl.ParseException: Invalid parse, found null
> at
> org.apache.metron.stellar.common.StellarCompiler$Expression.apply(StellarCompiler.java:211)
> at
> org.apache.metron.stellar.common.BaseStellarProcessor.parse(BaseStellarProcessor.java:145)
> at
> org.apache.metron.stellar.common.shell.DefaultStellarShellExecutor.executeStellar(DefaultStellarShellExecutor.java:401)
> at
> org.apache.metron.stellar.common.shell.DefaultStellarShellExecutor.execute(DefaultStellarShellExecutor.java:257)
> at
> org.apache.metron.stellar.common.shell.cli.StellarShell.execute(StellarShell.java:357)
> at org.jboss.aesh.console.AeshProcess.run(AeshProcess.java:53)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
> at java.lang.Thread.run(Thread.java:748){code}
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