Roundtrip failure for [AsArray [Int]]

[DavidEichmann]

This property fails: unflat @[AsArray [Int]] (flat (x :: [AsArray [Int]])) == Right x. I expect it to be true. here is a unit test case: x = [AsArray [1..3], AsArray [4..8]]

[DavidEichmann]

Note that the property holds when using AsList instead of AsArray

[tittoassini]

Hi David, apologies for the delay in answering your query.

The code as stated won't compile as x is not an [AsArray [Int]].

On the contrary:

unflat @[AsArray [Int]] (flat x )

will compile and fail, as it is to be expected as the serialisation of a AsList is different from that of AsArray.

Maybe I am missing the point?

[DavidEichmann]

@tittoassini Sorry about that, just a typo. I've updated my comment. It should have been x = [AsArray [1..3], AsArray [4..8]]. So:

λ> x = [AsArray [1..3], AsArray [4..8]]
λ> unflat @[AsArray [Int]] (flat (x :: [AsArray [Int]])) == Right x
False

When I was expecting True.

[tittoassini]

Oh oh, I think that you might actually have found a significant bug! I am currently travelling but I will look into it asap. Il giorno lun 25 ott 2021 alle ore 18:26 David Eichmann < ***@***.***> ha scritto:

…

@tittoassini <https://github.com/tittoassini> Sorry about that, just a typo. I've updated my comment. It should have been x = [AsArray [1..3], AsArray [4..8]]. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#23 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAAFRQO2WSQPRFWAJSPTCKDUIWAKPANCNFSM5ERH4E3A> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>.

-- Pasqualino "Titto" Assini http://networkpolitics.svbtle.com http://quid2.org/

[bezirg]

Hoping it would further help to catch the bug:
When using Int, it returns:

> tst $ [AsArray [(1::Int)..3], AsArray [4..8]]
(False,99,[129,1,2,3,0,65,2,2,131,3,132,0,0])

When using Word8, it returns:

> tst $ [AsArray [(1::Word8)..3], AsArray [4..8]]
(False,99,*** Exception: src/Flat/Bits.hs:50:7-72: Non-exhaustive patterns in Right (PostAligned _ f)

Also, both for int and word8:

> tst $ [AsArray [(1::Int)..3]]
(False,42,*** Exception: src/Flat/Bits.hs:50:7-72: Non-exhaustive patterns in Right (PostAligned _ f)

[tittoassini]

Thanks for your help and apologies for the monstrous delay in addressing this issue.

It should now be sorted (in github and soon in the 0.5 release).

It was due to a caching issue that occasionally caused the number of array elements to be overwritten incorrectly.

[DavidEichmann]

Thanks for sorting this, @tittoassini! 🥳