Getdataloader type bounds #4180
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The @NullMarked annotation on DataFetchingEnvironment makes type parameters implicitly non-null, but java-dataloader's DataLoader declares V extends @nullable Object to allow nullable values. This mismatch prevents Kotlin consumers from expressing nullable value types without unsafe casts when returning CompletableFuture from data fetchers. Add explicit V extends @nullable Object bound to match DataLoader's type signature, enabling proper nullability propagation to Kotlin.
bbakerman
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Nov 25, 2025
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bbakerman
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bbakerman
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Thanks for this.
Moving to JSpecify is an interesting exercise because while it "allows for more precise nullability specifications" its only the Kotlin compiler that truly enforces it.
So this mismatch for example survives a Java compile but not a Kotlin one.
I wonder if we are missing some Java setting that would catch this earlier
dondonz
modified the milestones:
26.x,
26.x breaking changes,
25.1 bugfix & non-breaking changes
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The @NullMarked annotation on DataFetchingEnvironment makes type parameters implicitly non-null, but java-dataloader's DataLoader declares V extends @nullable Object to allow nullable values.
This mismatch prevents Kotlin consumers from expressing nullable value types without unsafe casts when returning CompletableFuture from data fetchers.
Add explicit V extends @nullable Object bound to match DataLoader's type signature, enabling proper nullability propagation to Kotlin.
#4179