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https://issues.apache.org/jira/browse/DRILL-5070?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Paul Rogers resolved DRILL-5070.
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Resolution: Fixed
Fix Version/s: 1.10
Key fix was incorporated into DRILL-5052.
> Code gen: create methods in fixed order to allow test verification
> ------------------------------------------------------------------
>
> Key: DRILL-5070
> URL: https://issues.apache.org/jira/browse/DRILL-5070
> Project: Apache Drill
> Issue Type: Bug
> Affects Versions: 1.8.0
> Reporter: Paul Rogers
> Assignee: Paul Rogers
> Priority: Minor
> Fix For: 1.10
>
>
> A handy technique in testing is to compare generated code against a "golden"
> copy that defines the expected results. However, at present, Drill generates
> code using the method order returned by {{Class.getDeclaredMethods}}, but
> this method makes no guarantee about the order of the methods. The order
> varies from one run to the next. There is some evidence [this
> link|http://stackoverflow.com/questions/28585843/java-reflection-getdeclaredmethods-in-declared-order-strange-behaviour]
> that order can vary even within a single run, though a quick test was unable
> to reproduce this case.
> If method order does indeed vary within a single run, then the order can
> impact the Drill code cache since it compares the sources from two different
> generation events to detect duplicate code.
> This issue appeared when attempting to modify tests to capture generated code
> for comparison to future results. Even a simple generated case from
> {{ExpressionTest.testBasicExpression()}} that generates {{if(true) then 1
> else 0 end}} (all constants) produced methods in different orders on each
> test run.
> The fix is simple, in the {{SignatureHolder}} constructor, sort methods by
> name after retrieving them from the class. The sort ensures that method order
> is deterministic. Fortunately, the number of methods is small, so the sort
> step adds little cost.
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