[FLINK-35276] SortCodeGeneratorTest.testMultiKeys fails on negative zero

• Type: Bug
• Status: Open
• Priority: Critical
• Resolution: Unresolved
• Affects Version/s: 1.20.0, 1.19.1
• Component/s: Table SQL / Planner
• Labels: test-stability
• Assignee: Unassigned
• Reporter: Ryan Skraba
• Created: 30/Apr/24 13:49
• Updated: 30/Apr/24 13:50

Description

1.19 AdaptiveScheduler / Test (module: table) https://github.com/apache/flink/actions/runs/8864296211/job/24339523745#step:10:10757

SortCodeGeneratorTest can fail if one of the generated random row values is -0.0f.

Apr 28 02:38:03 expect: +I(,SqlRawValue{?},0.0,false); actual: +I(,SqlRawValue{?},-0.0,false)
Apr 28 02:38:03 expect: +I(,SqlRawValue{?},-0.0,false); actual: +I(,SqlRawValue{?},0.0,false)
...
<snip>
...
Apr 28 02:38:04 expect: +I(,null,4.9695407E17,false); actual: +I(,null,4.9695407E17,false)
Apr 28 02:38:04 expect: +I(,null,-3.84924672E18,false); actual: +I(,null,-3.84924672E18,false)
Apr 28 02:38:04 types: [[RAW('java.lang.Integer', ?), FLOAT, BOOLEAN]]
Apr 28 02:38:04 keys: [0, 1]] 
Apr 28 02:38:04 expected: 0.0f
Apr 28 02:38:04  but was: -0.0f
Apr 28 02:38:04 	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
Apr 28 02:38:04 	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
Apr 28 02:38:04 	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
Apr 28 02:38:04 	at org.apache.flink.table.planner.codegen.SortCodeGeneratorTest.testInner(SortCodeGeneratorTest.java:632)
Apr 28 02:38:04 	at org.apache.flink.table.planner.codegen.SortCodeGeneratorTest.testMultiKeys(SortCodeGeneratorTest.java:143)
Apr 28 02:38:04 	at java.lang.reflect.Method.invoke(Method.java:498)

In the test code, this is extremely unlikely to occur (one in 2²⁴?) but has happened at this line (when the rnd.nextFloat() is 0.0f and rnd.nextLong() is negative:

https://github.com/apache/flink/blob/e7ce0a2969633168b9395c683921aa49362ad7a4/flink-table/flink-table-planner/src/test/java/org/apache/flink/table/planner/codegen/SortCodeGeneratorTest.java#L255

We can reproduce the failure by changing how likely 0.0f is to be generated at that line.