Failed calls to readFully method of client-utils package

[Jorge-Lopes]

Describe the bug

When using the readFully method from the agoric client-utils package, the following error occurs:
TypeError: Cannot read properties of undefined (reading 'readAt').
This issue originates from the code here.

The same issue also affects other methods in the makeVStorage function of the vstorage-kit module. The problem stems from the usage of the this keyword, causing instance method invocations to fail.

To Reproduce

Steps to reproduce the behavior:

1. Go to Draft PR test(a3p): extend governance test coverage for acceptance proposal #10555
2. Re-run the CI action test-docker-build
3. See error message

Expected behavior

The readFully method should correctly return the values stored in a specific node, recorded after a given block height.

Platform Environment

OS: macOS Sequoia v15.0.1
Node.js: v20.9.0
Agoric-SDK: agoric-upgrade-16av-1130-g753242866

Screenshots

Relevant CI Logs:

  Rejected promise returned by test. Reason:

  TypeError {
    message: 'Cannot read properties of undefined (reading \'readAt\')',
  }

  TypeError: Cannot read properties of undefined (reading 'readAt')
      at readFully (file:///usr/src/agoric-sdk/packages/client-utils/src/vstorage-kit.js:102:49)
      at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
      at async getGovernanceProposalsHistory (file:///usr/src/proposals/z:acceptance/test-lib/governance.js:228:22)
      at async file:///usr/src/proposals/z:acceptance/governance.test.js:184:19

[Jorge-Lopes]

cc: @Chris-Hibbert

[turadg]

This is not a bug. Your diagnosis is correct that it's missing this, but that's because you're using an instance method as a naked function. Instead, pass the vstorage object.

If you want to be able to pass the functions without their instance object that's a feature request. I don't think we need it but if you really do you can update the body and labels and re-open this. Second thought, it would be easier to support this than document it as a limitation