sui: [Bug] take_last_created_owned does not return the latest created object

Steps to Reproduce Issue

When calling test_scenario::take_last_created_owned in a test sequence, the returned object is not always the latest created.

Will provide code to reproduce in first comment.

Expected Result

I expect that test_scenario::take_last_created_owned to return the last created object of type T created.

Actual Result

test_scenario::take_last_created_owned is not always returning the last created object, this is deterministic, but the number of objects to cause this differs, I belive based on some kind of checksum but I don’t know. Funcs such as test_scenario::get_account_owned_inventory are not public to help me debug this.

System Information

OS: Windows 10
Compiler: VS2022 / Sui Move 0.6.1

About this issue

Original URL
State: closed
Created 2 years ago
Comments: 16 (10 by maintainers)

Most upvoted comments

Can someone else help with the Windows issue? Maybe @patrickkuo or @longbowlu ?

That’s known issue and we have a fix in one of the build.rs, the move compiler require more stack when running in windows…

I will create a PR to fix it in sui move

patrickkuo on Jul 29, 2022

PR #3620 should fix this issue. I have also added the repro code as a test case. Thanks for reporting! @jamescarter-le

emmazzz on Jul 29, 2022

Took a look at this. I believe there is indeed an issue with the native implementation of test_scenario module. In the implementation, we grab all the objects owned by the address, pop an object from the back, and return the object. However, the object inventory is implemented using a BTreeMap which does not preserve the insertion order of entries: https://github.com/MystenLabs/sui/blob/main/crates/sui-framework/src/natives/test_scenario.rs#L55

Instead the entries will be sorted by the keys (ObjectId). Therefore when we pop_back, we don’t get the most recent created/inserted object. The easiest fix I can think of is to use a different map that does preserve the insertion order. If no such map exists, we can include the insertion order in the value of the entry and sort using values. I will try out the approaches and put up a PR later.

emmazzz on Jul 29, 2022

@emmazzz Can you help take a look?

lxfind on Jul 29, 2022

As an aside, how can I debug this myself? Do I need to recompile sui making changes to test_scenario, or can I create a copy of test_scenario in my module and modify this so I can get access to it’s internally state for debugging? Being able to step through this code would be very helpful.

I will try to look into it later today, but if you’d like to try digging in yourself then I’d follow the first approach you describe. The instructions on how to build and test Sui locally can be found here

The test_scenario package consists of both Move code and native functions implemented in Rust. There is no Move debugger at the moment, but technically you could indeed step through the Rust code - we don’t have official instructions on how to set it up in this context, though.

awelc on Jul 28, 2022