Revert use of WeakReferences for SbtUpdateReport cached values
#564
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eed3si9n
approved these changes
Jun 2, 2025
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Fixes sbt/sbt#8150
In #563, I chose to wrap the cache map's values in
WeakReferencebecause in heap dumps I was seeing a lot ofsbt.librarymanagement.Artifactandsbt.librarymanagement.ModuleIDs mentioned as values thatSbtUpdateReportwas referencing. UsingWeakReferencecaused them to go away.The result of using it is that the map's values could be garbage collected before its keys, leading to map entries with
nullvalues and causingNullPointerExceptions.Looking more closely at the heap dumps, I don't think the
Artifacts andModuleIDs are part of the original memory leak issue, so it should be fine to removeWeakReference. WithoutWeakReferencethe number of them doesn't grow linearly with the number of updates, nor does the retained heap ofSbtUpdateReport.@eed3si9n do you mind taking a look?