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Mix in theproductPrefix hash statically in case classhashCode#11023
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lrytz commentedMar 20, 2025
The attemt to keep Not sure if that's a big issue... |
This was referencedMar 20, 2025
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classOf[C].getName instead ofproductPrefix in casehashCodeproductPrefix hash statically in case classhashCodeUh oh!
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11b1efa to37a12baComparesjrd approved these changesMar 21, 2025
2ea7949 todedfce3CompareSince 2.13, case class `hashCode` mixes in the hash code of the`productPrefix` string. This is inconsistent with the `equals` method,subclasses of case classes that override `productPrefix` compareequal but have a different `hashCode`.This commit changes `hashCode` to mix in the `productPrefix.hashCode`statically instead of invoking `productPrefix` at runtime.For case classes without primitive fields, the synthetic `hashCode`invokes `ScalaRunTime._hashCode`, which mixes in the result of`productPrefix`. To fix that, the synthetic hashCode is changedto invoke `MurmurHash3.productHash` directly and mix in the nameto the seed statically. This works out with keeping `productHash`forwards and backwards compatible.The `MurmurHash3.productHash` method is deprecated / renamed to`caseClassHash`. This method computes the same hash as the synthetic`hashCode`, except for the corner case where a case class(or a subclass) override the `productPrefix`. In this case, thecase class name needs to be passed manually to `caseClassHash`.
| }else { | ||
| if (arr==0) | ||
| if (!ignorePrefix) x.productPrefix.hashCodeelse seed | ||
| else { |
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rare case where I would retain extra braces (Scala 2)
| defensureAccessible(m:JMethod):JMethod= scala.reflect.ensureAccessible(m) | ||
| // This is called by the synthetic case class `toString` method. | ||
| // It originally had a `CaseClass` parameter type which was changed to `Product`. |
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"originally" here means like first verse of Genesis
lrytz added a commit to scala/scala3 that referenced this pull requestApr 3, 2025
…22865)Since 2.13, case class `hashCode` mixes in the hash code of the`productPrefix` string. This is inconsistent with the `equals` method,subclasses of case classes that override `productPrefix` compare equalbut have a different `hashCode`(scala/bug#13033).This commit changes `hashCode` to mix in the `productPrefix.hashCode`statically instead of invoking `productPrefix` at runtime.For case classes without primitive fields, the synthetic `hashCode`invokes `ScalaRunTime._hashCode`, which mixes in the result of`productPrefix`. To fix that, the synthetic hashCode is changed toinvoke `MurmurHash3.productHash` directly and mix in the name to theseed statically.Scala 3 forward port ofscala/scala#11023
4345ced intoscala:2.13.x 3 checks passed
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hamzaremmal pushed a commit to hamzaremmal/scala3 that referenced this pull requestMay 2, 2025
Mix in the `productPrefix` hash statically in case class `hashCode`
hamzaremmal pushed a commit to scala/scala3 that referenced this pull requestMay 7, 2025
Mix in the `productPrefix` hash statically in case class `hashCode`
dongjoon-hyun pushed a commit to apache/spark that referenced this pull requestOct 13, 2025
### What changes were proposed in this pull request?Upgrade to scala 2.13.17### Why are the changes needed?To bring the latest bug fixes and improvements like JDK 25 support. Note that Scala community announces two breaking changes due to the bug fixes.> Breaking changes> - Mix in the productPrefix hash statically in case class hashCode> - Improve scala.util.Using suppression order-https://github.com/scala/scala/releases/tag/v2.13.17 -scala/scala#11046 -scala/scala#10937 -scala/scala#10927 -scala/bug#13058 -scala/scala#11023 -scala/bug#13033 -scala/scala#11000### Does this PR introduce _any_ user-facing change?No### How was this patch tested?local and github builds### Was this patch authored or co-authored using generative AI tooling?NoCloses#52509 from vrozov/SPARK-53585.Authored-by: Vlad Rozov <vrozov@amazon.com>Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>
huangxiaopingRD pushed a commit to huangxiaopingRD/spark that referenced this pull requestNov 25, 2025
### What changes were proposed in this pull request?Upgrade to scala 2.13.17### Why are the changes needed?To bring the latest bug fixes and improvements like JDK 25 support. Note that Scala community announces two breaking changes due to the bug fixes.> Breaking changes> - Mix in the productPrefix hash statically in case class hashCode> - Improve scala.util.Using suppression order-https://github.com/scala/scala/releases/tag/v2.13.17 -scala/scala#11046 -scala/scala#10937 -scala/scala#10927 -scala/bug#13058 -scala/scala#11023 -scala/bug#13033 -scala/scala#11000### Does this PR introduce _any_ user-facing change?No### How was this patch tested?local and github builds### Was this patch authored or co-authored using generative AI tooling?NoClosesapache#52509 from vrozov/SPARK-53585.Authored-by: Vlad Rozov <vrozov@amazon.com>Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>
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Since 2.13, case class
hashCodemixes in the hash code of theproductPrefixstring. This is inconsistent with theequalsmethod, subclasses of case classes that overrideproductPrefixcompare equal but have a differenthashCode.This commit changes
hashCodeto mix in theproductPrefix.hashCodestatically instead of invokingproductPrefixat runtime.For case classes without primitive fields, the synthetic
hashCodeinvokesScalaRunTime._hashCode, which mixes in the result ofproductPrefix. To fix that, the synthetic hashCode is changed to invokeMurmurHash3.productHashdirectly and mix in the name to the seed statically. This works out with keepingproductHashforwards and backwards compatible.The
MurmurHash3.productHashmethod is deprecated / renamed tocaseClassHash. This method computes the same hash as the synthetichashCode, except for the corner case where a case class (or a subclass) override theproductPrefix. In this case, the case class name needs to be passed manually tocaseClassHash.Fixesscala/bug#13033