Develop tooling to make it easier to generate XDR test cases for CAPs

[sisuresh]

What problem does your feature solve?

We'd like to add tooling to generate test XDR for CAPs in development, which will allow downstream systems to integrate sooner.

[sisuresh]

Some other ideas to look into from @leighmcculloch -

1. Descriptions of property tests so that downstream can rapidly build their own tests using generated inputs to validate what they build.
2. A rapidly developed xdr generator built as part of the design process.

[leighmcculloch]

add tooling to generate test XDR for CAPs in development

@sisuresh What are you thinking will be inputs to this tooling?

I had imagined that this would probably need to be somewhat hand crafted, or coded per CAP in the form of scripts, using one of the xdr libraries, although maybe LLM tooling could help short circuit that.

[sisuresh]

add tooling to generate test XDR for CAPs in development

@sisuresh What are you thinking will be inputs to this tooling?

I had imagined that this would probably need to be somewhat hand crafted, or coded per CAP in the form of scripts, using one of the xdr libraries, although maybe LLM tooling could help short circuit that.

I've been thinking of this in the context of LLMs to save time. Essentially a way to handcraft XDR quickly -

1. stellar-xdr schema.
2. A thorough business logic spec with rules on what is allowed.
3. Examples of existing operations and scenarios.

And then for a specific CAP change -

1. We'd specify any changes to the business logic spec required for the new CAP.
2. We specify detailed changes to an existing example to adapt it for the CAP.

The issue with this idea is that we don't have a good way to validate the generated xdr. Depending on the change, eyeballing might be sufficient. That's something we'll need to figure out. I tried something like what I mentioned above here, but the generated xdr had some issues (for example, it made up an event). I didn't spend much time on it though and I think it could work well given more time.

[leighmcculloch]

I took a stab at doing something like this. It was okay, I think. It was at least a starting place. I had the agent in the stellar-core repo so it could analyse the code. The prompt I used was this:

I'd like to pretend we're implementing CAP-73 linked below.

https://github.com/stellar/stellar-protocol/blob/master/core/cap-0073.md

A CAP describes changes to the stellar protocol, implemented by stellar-core (this project). Think as if you are implementing it. Identifying all the changes to LedgerCloseMeta that will be required, that should be specified in the CAP. Then identifying all of the downstream impact, tracing where new fields will get there values, and where changed fields will get there values.

Once you have fully traced and fully understand how the change will impact the code, the obvious effects as well as the more elusive side-effects: Then you are ready. And the final task is to produce 20 LedgerCloseMeta values using the stellar-xdr cli tool (use it's json schema https://stellar.org/schema/xdr-json/v25.0.0/LedgerCloseMeta.json).

Write the text LedgerCloseMeta as json files in an examples/ directory.

It generated these files:

• examples.zip

#	File	Description
01	01-trust-create-alphanum4.json	Trust creating USDC (4-char) trustline
02	02-trust-create-alphanum12.json	Trust creating STELLARTOKEN (12-char) trustline
03	03-trust-existing-trustline-noop.json	Trust on existing trustline (no-op)
04	04-trust-c-address-noop.json	Trust with contract address (no-op)
05	05-trust-issuer-not-exist-fail.json	Trust when issuer doesn't exist (failed)
06	06-trust-self-asset-fail.json	Trust for own asset (failed)
07	07-trust-low-reserve-fail.json	Trust with insufficient reserve (failed)
08	08-trust-with-auth.json	Trust with SorobanAuthorizationEntry
09	09-xlm-transfer-create-account.json	XLM transfer creating new account
10	10-xlm-transfer-from-create-account.json	XLM transfer_from creating new account
11	11-xlm-transfer-existing-account.json	XLM transfer to existing account
12	12-xlm-transfer-below-minimum-fail.json	Transfer below 1 XLM minimum (failed)
13	13-xlm-transfer-exact-minimum.json	Transfer exactly 10000000 stroops
14	14-xlm-transfer-c-address.json	XLM transfer to contract (no account creation)
15	15-xlm-transfer-new-account-auth.json	New account creation with auth
16	16-combined-trust-then-transfer.json	Trust then transfer in single tx
17	17-multiple-trustlines-single-tx.json	Multiple trustlines in single tx
18	18-xlm-create-multiple-accounts.json	Create multiple accounts via XLM transfers
19	19-mixed-classic-soroban.json	Mixed classic (Payment, ChangeTrust) + Soroban CAP-73
20	20-protocol-upgrade-with-cap73.json	Protocol upgrade to v27 with CAP-73 trust call