chore: Matching on seq #2561
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chore: Matching on seq #2561
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pjfanning
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Dec 8, 2025
| fromGraph(new IterableSource[T](iterable)).withAttributes(DefaultAttributes.iterableSource) | ||
| } | ||
| def apply[T](iterable: immutable.Iterable[T]): Source[T, NotUsed] = iterable match { | ||
| case immutable.Seq() => empty[T] |
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I don't see how adding extra checks, including instanceof checks, improves performance. Is there any way that we could keep a variant of the old code from the recent other PR that introduced changes?
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It's vs the materialization
pjfanning
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Dec 8, 2025
| def apply[T](iterable: immutable.Iterable[T]): Source[T, NotUsed] = iterable match { | ||
| case immutable.Seq() => empty[T] | ||
| case immutable.Seq(elem: T @unchecked) => single(elem) | ||
| case other => (other.knownSize: @switch) match { |
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Can you add a comment saying that if the Iterable has unknown size, that knownSize returns -1?
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It's not unknown size,just the size can or not been cheaply cimputed
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#2562 is merged |
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@pjfanning Cool~ |
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The pr against Scala is rejected, so I need to handle it here.