Outdated or incorrect binary serialization API

[Aurora2500]

Your Godot version:
3.3 Stable

Issue description:
In the documentation, it is stated that

All packets have a 4-byte header representing an integer, specifying the type of data.
Following this is the actual packet contents, which varies for each type of packet.

Because of this, I'd expect 4 bytes being taken up as a header, indicating which type it is and some other flag information. And then following that I'd get the data for the type, if any.

So when doing store_var(null), I'd expect there to be 4 bytes all filled with 0:

00000000 00000000 00000000 00000000

Or when doing store_var(42), I'd expect to get a file with the following binary data:

00000010 00000000 00000000 00000000
00101010 00000000 00000000 00000000

But instead, there seems to be an extra 4 bytes in front of the header for each data packet.
When I store null, I get:

00000100 00000000 00000000 00000000
00000000 00000000 00000000 00000000

Or when I store 42:

00001000 00000000 00000000 00000000
00000010 00000000 00000000 00000000
00101010 00000000 00000000 00000000

The documentation does not indicate what these extra bytes mean, or mention that they should exist at all.

URL to the documentation page:
https://docs.godotengine.org/en/stable/tutorials/misc/binary_serialization_api.html

[Calinou]

See also #4887 and #4893.

[BLNJ]

This problem is much bigger, there are actually 38 different packet types which you only discover when directly looking at the source code (for instance Vector2I, Rect2I, Vector3I and so on) or when you implement the types by following the documentation but notice that everything after vector2 (ID 5) is off.
It is also said that all packets have a 4 byte header, but nowhere is mentioned that packets have a size in the header, while packets inside others (like in dictionary) dont have that size component in the header.

Im currently slowly working my way through all possible types. Generating the files by the engine, looking at them in a hex editor and incorporating that into my own library. Im going to update the documentation when Im done

[KryziK]

Hey all,

Full disclosure, I had Claude help me analyze marshalls.h and marshalls.cpp to produce this. If this isn't allowed, please just inform me rather than berate or attack me. This is a learning experience for me.

I cross-checked it with a save file for a Godot game that I have and it seemed to match. I used ImHex and a custom pattern and the structures it produced looked good to me.

Here's a rough first draft of the new RST documentation. I haven't had a chance to figure out how to "build" it locally so I can preview it in the same format and theme of the Godot website.

This is for godot-4.4.1-stable.
File removed by me so as not to steer anyone in the wrong direction with regards to AI and code quality

I plan to make a PR once I have time to actually review the differences, but I figured I'd put it here in case anyone else wanted to get a head start on it.

Thanks for your time.

[AThousandShips]

If this isn't allowed, please just inform me rather than berate or attack me.

No one is going to do that, don't worry

However we do not accept AI generated contributions, but also the documentation should be updated for 4.5.1 at least to make it up to date

But to be clear: Do not make a contribution if the text is written by AI, you need to write it yourself, and if you use AI to assist you, you need to explain how that was involved

[KryziK]

Thank you for the informative reply! I will download 4.5.1 and follow your advice to manually write up the document while explaining how AI was involved in understanding the data structures.

Would it be okay to upload that in this thread here for review (before a PR), or should I go directly to submitting a PR?

[AThousandShips]

Just go ahead and make a PR and I'll take a look

[KryziK]

Just go ahead and make a PR and I'll take a look

#11517