Caller is origin implementation

[ramirez7358]

Summary

Closes #_

• [n] y/n | Does it introduce breaking changes?
• [n] y/n | Is it dependant on the specific version of cargo-contract or pallet-contracts?

Description

Function

caller_is_origin()

Initial status

Not implemented in integration test

Issue documentation & test case

https://github.com/CoinFabrik/on-ink-integration-tests/tree/main/test-cases/caller-is-origin

Implementation note

We have added the depthfield to the ExecContext struct in order to be able to detect caller chages avery time calls are made between contracts.

Basically every time the callee changes in the instantiate_contract or invoke_contract function calls, one is aded to depth. And when the callee returns to the previous one, 1 is subtracted.

The caller_is_origin()function compares the value of depth to zero to check if the current contract caller is the origin of the entire call stack.

Testing guide

In the directory integration-tests/set_contract_storage of the target directory, we include in our pull request a test case showing that the observed implementation difference has been corrected. Note that this test is different from the original test case in our repository, which showed the difference.

In order to run the integration tests run:
cargo test

In order to run the e2e tests run:
cargo test -–features e2e-tests

These tests are run separately because we do not need to compare their results.

Checklist before requesting a review

• My code follows the style guidelines of this project
• I have added an entry to CHANGELOG.md
• I have commented my code, particularly in hard-to-understand areas
• I have added tests that prove my fix is effective or that my feature works
• Any dependent changes have been merged and published in downstream modules