Auto-gen Python Exchange wrapper

[feuGeneA]

Fixes #1888 .

Description

Include Exchange in the list of ABI's that packages/python-contract-wrapper is currently generating wrappers for, and change python-packages/contract_wrappers to pull in that code (overwriting the existing, manually-written wrapper) before linting and testing itself. Existing tests/examples should all pass with minimal changes (ideally none).

Testing instructions

Since the end result is generated code, reviewing that code (and the docs generated from it) is the first step in testing.

I found some CircleCI configuration to persist "Build Artifacts," which accurately describes our generated code. With this, you can go to a build job's "Artifacts" tab (here's a link to the "Artifacts" tab on a recent run of test-python), and drill down through the repo tree to find persisted artifacts.

I'm using this to persist generated Python wrappers, generated test output from abi-gen's command-line tests, and documentation generated from the Python code. Here are the links to the artifacts from the latest CircleCI run:

• Generated Python Exchange wrapper
• contract_wrappers.py generated documentation (includes docs for the Exchange wrapper class)
• Generated Python ERC20Token wrapper

---

If you want to actually run the generation process yourself:

0x-monorepo/python-packages$ ./pre_install
0x-monorepo/python-packages$ ./install_editable
0x-monorepo/python-packages/contract_wrappers$ PKG=@0x/python-contract-wrappers yarn build && ./setup.py pre_install && ./setup.py lint && ./setup.py test
[edit code]
0x-monorepo/python-packages/contract_wrappers$ PKG=@0x/python-contract-wrappers yarn build && ./setup.py pre_install && ./setup.py lint && ./setup.py test
[repeat]

Types of changes

• New feature (non-breaking change which adds functionality)

Checklist:

• Rename contract methods parameters in existing exchange contract to match contract method parameter names
• Rename existing wraper from exchange_wrapper.py to just exchange.py.
• Fix faulty encoding of Order struct tuple in generated wrapper methods. See CI failure.
• Generate documentation from the generated wrapper and make sure it looks okay.
• Document bytes parameter methods as requiring a UTF-8 encoding.
• Stop generating TypedDicts for structs that are only used as the return value for non-const methods, since there's no generated reference to such a TypedDict, because those return values aren't accessible since a non-const method can only return a transaction hash.
• Document flags used in abi-gen/diff.sh. Also, move that diff.sh into test-cli, since that's the only place it's ever used, and remove the parameters, since it's always called with the same arguments, and also rename it to run_diff_test.sh.
• In abi-gen/test-cli/fixtures/contracts/AbiGenDummy.sol, rename Event to AnEvent.
• .gitignore JSON schema files in python package area, and also generated wrappers in python area.
• Review old, manually-written wrapper to see if there are other things that need to be ported over.
• Add JSON schema validation.
• Rebase on development in order to fix test-publish failure.
• Add signature validation. Decided not to do this; see comment below.
• Add new entries to the relevant CHANGELOG.jsons.
• When generated methods are called with view_only=True (to do an eth_call instead of an eth_sendTransaction) the method should return the value returned by the method, not return a transaction hash.
• Fix bug with wrong return value for some generated methods, shown in this comment below.
• Raise follow-on Issue: Add refined types to output values of get_*_event() methods. Currently they're all just Tuple[AttributeDict].
• Raise follow-on Issue: Add support for accepting signatures as strings (not just bytes).

[coveralls]

Coverage decreased (-0.1%) to 83.121% when pulling 0f6cd5d on feature/python/generate-exchange-wrapper into c59d886 on development.

[feuGeneA]

This branch is currently in a good checkpoint state. The Exchange contract is being generated and run through the tests and doctest examples with every build, and are clean in CircleCI (except for the test-publish failure, quoted below).

However, generated wrappers are currently not yet doing any JSON schema validation, nor any signature validation. There may also be other specially crafted logic in there too, which would need to be ported over, but at this time all of the examples/tests are using this generated wrapper and passing. These omissions are reflected in the checklist in the PR description.

The generated Exchange wrapper, as of this point in time, can be seen here: https://gist.github.com/feuGeneA/de3754c87d3732e8a2e2e69e53da78de

The pre-existing, manually-written Exchange wrapper, can be seen in the commit that deleted it.

For the reviewer's convenience, here is a diff of the two: https://www.diffchecker.com/7tEnPG7v . Sadly, there is a lot of change in the diff.

test-publish is failing with

ERROR in package @0x/contracts-exchange:
Command failed: npm install --save @0x/[email protected] --registry=http://localhost:4873/
npm WARN deprecated [email protected]: This module is no longer maintained, try this instead:
npm WARN deprecated   npm i nyc
npm WARN deprecated Visit https://istanbul.js.org/integrations for other alternatives.

🤷‍♂️ a re-run didn't fix it...

[feuGeneA]

@fabioberger @xianny @PirosB3 this PR is pretty big, but not as big as it looks.

It says I added 2,300 new lines of code, but a lot of that is generated: expected outputs for those new abi-gen CLI tests, pre-compiled contract artifacts for abi-gen test fixtures, etc.

And there are 30 commits, but many of them are very small. There are maybe 2 or 3 commits that are pretty big and hairy, and maybe 3 or 4 medium sized ones, and the rest are small to tiny.

[fabioberger]

Looking great @feuGeneA! 🎉