Regression: getting "storage used is not initialized or not initialized correctly" error when trying to borrow or check capability on non existent account

[assaf-anchor]

Instructions

Please fill out the template below to the best of your ability and include a label indicating which tool/service you were working with when you encountered the problem.

Problem

<what is the problem you've encountered?>

Getting an error when executing a script that tries to borrow or check capability on an account that hasn't be created yet:

failed to update storage used by key #7075626c6963 on account 0000000000000000: account 0000000000000000 storage used is not initialized or not initialized correctly

This wasn't erroring before (on emulator v0.26.0) but errors on v0.29.0.

Steps to Reproduce

<share any logs/screenshots or steps to replicate>

Repro using this script with arg 0x0 (or any non existing account):

import LockedTokens from 0xf8d6e0586b0a20c7

pub fun main(address : Address) {
   let account = getAccount(address)
   let cap = account.getCapability<&LockedTokens.TokenHolder{LockedTokens.LockedAccountInfo}>(LockedTokens.LockedAccountInfoPublicPath)
   cap.check()
}

The same error also happens with similar calls like FlowStakingCollection.doesAccountHaveStakingCollection which also tries to borrow a capability

Acceptance Criteria

This should not error to keep the behavior of the previous version. Alternatively, there should be some API to check if an account exists (returning a bool) or someway to catch this specific error in case we want to ignore it.

Context

<what are you currently working on that this is blocking?> I want to check balances of various addresses, and if they don't exist just return 0. Is there a workaround? Is checking that the account's storageCapacity is greater than 0 a good idea or any other recommendation?

[devbugging]

Thank you for the report, this is interesting, will take a look and report back.

[assaf-anchor]

additionally, accessing account.storageUsed also causes an error:

 failed to submit executable script: client: rpc error: code = Unknown desc = [Error Code: 1101] cadence runtime error Execution failed:
error: getting storage used failed: account 0000000000000000 storage used is not initialized or not initialized correctly
 --> 79802cd6e2945636fd595e3b4d53ac3721c8b907976856cb79cbef484f8b8ff1:5:3
  |
5 |    if account.storageUsed > 0 {
  |    ^

[devbugging]

@assaf-anchor can you also reproduce the same bug on testnet?

[assaf-anchor]

looks like it's also happening on testnet for storageUsed

$ cat script.cdc
pub fun main(): UInt64 {
   let account = getAccount(0x0)
   let i = account.storageUsed
   return i
}

$ curl -H 'Content-type: application/json' -d '{"script":"'$(cat script.cdc | base64 -w 0)'", "arguments":[]}' https://rest-testnet.onflow.org/v1/scripts
{
        "code": 400,
        "message": "Invalid Flow argument: failed to execute the script on the execution node execution-5f6c73a22445d7d958c6a37c1f3be99c72cacd39894a3e46d6647a9adb007b4d@execution-001.devnet33.nodes.onflow.org:3569=100: rpc error: code = InvalidArgument desc = failed to execute script: failed to execute script at block (dfc373f193364a7f69943139daef274522cd27a60774f3daf73b924a1db4e725): [Error Code: 1101] cadence runtime error Execution failed:\nerror: getting storage used failed: account 0000000000000000 storage used is not initialized or not initialized correctly\n --\u003e 989f55d70b5a6e27f78b39055078c9895a2a29f3c66ede7cae8b642092d98756:3:3\n  |\n3 |    let i = account.storageUsed\n  |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^\n"
}

However, for capability check it doesn't error on testnet

import LockedTokens from 0x95e019a17d0e23d7

pub fun main() {
   let account = getAccount(0x0)
   let cap = account.getCapability<&LockedTokens.TokenHolder{LockedTokens.LockedAccountInfo}>(LockedTokens.LockedAccountInfoPublicPath)
   cap.check()
}

$ curl -H 'Content-type: application/json' -d '{"script":"'$(cat script.cdc| base64 -w 0)'", "arguments":[]}' https://rest-testnet.onflow.org/v1/scripts
"eyJ0eXBlIjoiVm9pZCJ9Cg=="

[devbugging]

I see. Well, the fact this fails is OK but I think the confusing part is the error description (I believe the address returned is just an empty address). It might be how Cadence handles a failure when fetching a capability. Just to double-check I will ping @turbolent from Cadence.

[bluesign]

Tracked here: https://github.com/onflow/flow-go/issues/3387