Fix wrong use of map of Set for summation

[sezruby]

What is the context for this pull request?

• Tracking Issue: n/a
• Parent Issue: n/a
• Dependencies: n/a

What changes were proposed in this pull request?

Fix a bug in IndexLogEntry.sourceFilesSzieInBytes.
Set.map(_.size).sum returns incorrect results.

Does this PR introduce any user-facing change?

Yes, fixes the bug.

How was this patch tested?

tested by unit tests in #272

[imback82]

tested by unit tests in #272

Can we add simple tests in this PR? It's weird that tests are done by a different PR.

[imback82]

Set.map(_.size).sum returns incorrect results.

I wasn't aware of this. Could you explain a bit more? Set(1, 2, 3).map(a => a).sum seems fine?

[sezruby]

Set(((a,1), (b,1)).map(_._2).sum returns 1 it's because map result became Set, not Seq..

[sezruby]

Can we add simple tests in this PR? It's weird that tests are done by a different PR.

Not sure this PR needs a separate test..

[imback82]

Not sure this PR needs a separate test..

How did you verify the fix then?

[sezruby]

@imback82 Updated a simple test. Thanks!

[imback82]

LGTM, thanks @sezruby!

[imback82]

Set(((a,1), (b,1)).map(_._2).sum returns 1 it's because map result became Set, not Seq..

👍🏼