Serialization compatibility

Domenico Di Giulio

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Mar 22, 2021, 6:03:08 AM3/22/21

to fastutil

I am currently using fastuil 8.3.0, and planning to upgrade to 8.5.2. My concern is about compatibility of serialized collections, which may be broken by any fix applied.

Can a fastutil collection serialized with version 8.3.0 be deserialized by version 8.5.2 ? Is there an overall policy with respect to serialization compatibility ?

Here is a list of the classes that I'm using:

it.unimi.dsi.fastutil.longs.Long2ObjectMap.FastEntrySet

it.unimi.dsi.fastutil.longs.Long2ObjectMap

it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap

it.unimi.dsi.fastutil.longs.LongIterator

it.unimi.dsi.fastutil.longs.LongOpenHashSet

it.unimi.dsi.fastutil.longs.LongSet

it.unimi.dsi.fastutil.objects.Object2IntOpenHashMap

it.unimi.dsi.fastutil.objects.Object2LongMap

it.unimi.dsi.fastutil.objects.Object2LongOpenHashMap

it.unimi.dsi.fastutil.objects.Object2ObjectMap.Entry

it.unimi.dsi.fastutil.objects.Object2ObjectMap.FastEntrySet

it.unimi.dsi.fastutil.objects.Object2ObjectMap

it.unimi.dsi.fastutil.objects.Object2ObjectOpenHashMap

it.unimi.dsi.fastutil.objects.ObjectArrayList

it.unimi.dsi.fastutil.objects.ObjectIterator

it.unimi.dsi.fastutil.objects.ObjectLinkedOpenHashSet

it.unimi.dsi.fastutil.objects.ObjectList

it.unimi.dsi.fastutil.objects.ObjectLists

it.unimi.dsi.fastutil.objects.ObjectOpenHashSet

it.unimi.dsi.fastutil.objects.ObjectSet

Thanks for your help.

Sebastiano Vigna

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Mar 23, 2021, 6:25:05 PM3/23/21

to fastutil

Il giorno lunedì 22 marzo 2021 alle 10:03:08 UTC Domenico Di Giulio ha scritto:

I am currently using fastuil 8.3.0, and planning to upgrade to 8.5.2. My concern is about compatibility of serialized collections, which may be broken by any fix applied.

Can a fastutil collection serialized with version 8.3.0 be deserialized by version 8.5.2 ? Is there an overall policy with respect to serialization compatibility ?

Sincerely: not. You have two ways to check this:

- a git diff with 8.3.0, looking for modifications of serialVersionUIDs.

- save with 8.3.0 and load with 8.5.2.

I gave a quick look and I don't think there should be any problem, but to be 100% sure the second test is your best bet.

seba

Domenico Di Giulio

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Mar 24, 2021, 11:36:47 AM3/24/21

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Thanks, I tried the following and it worked in both cases with no issues:

- saved with 8.3.0 and loaded with 8.5.2

- saved with 8.5.2 and loaded with 8.3.0

Anyway, I understand there is no policy to keep serialization compatibility across versions.

In the future, would you consider the chance to keep track of any changes that break serialization compatibility in the change log ?

Thanks a lot, you can't imagine how important is this package for us.

Sebastiano Vigna

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Mar 24, 2021, 2:45:36 PM3/24/21

to fastutil

Il giorno mercoledì 24 marzo 2021 alle 15:36:47 UTC Domenico Di Giulio ha scritto:

Thanks, I tried the following and it worked in both cases with no issues:
- saved with 8.3.0 and loaded with 8.5.2
- saved with 8.5.2 and loaded with 8.3.0

Anyway, I understand there is no policy to keep serialization compatibility across versions.
In the future, would you consider the chance to keep track of any changes that break serialization compatibility in the change log ?

Well, actually that's what I do usually. If you peruse CHANGES looking for "break" you'll find a report every time I know there's a break.

Ciao,

seba

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