Circular dependencies in @substrate/smoldot-light

[jacogr]

When including the package in a rollup build, it has some complaints. (Generally, apart from madge the rollup bundler is actually quite good at sniffing out these things). The full output from rollup is as follows -

packages/api/build/bundle.js → packages/api/build/bundle-polkadot-api.js...
(!) `this` has been rewritten to `undefined`
https://rollupjs.org/guide/en/#error-this-is-undefined
node_modules/@substrate/smoldot-light/dist/mjs/client.js
2: // Copyright (C) 2019-2022  Parity Technologies (UK) Ltd.
3: // SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
4: var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
                    ^
5:     function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
6:     return new (P || (P = Promise))(function (resolve, reject) {
...and 1 other occurrence
node_modules/@substrate/smoldot-light/dist/mjs/instance/instance.js
2: // Copyright (C) 2019-2022  Parity Technologies (UK) Ltd.
3: // SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
4: var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
                    ^
5:     function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
6:     return new (P || (P = Promise))(function (resolve, reject) {
...and 1 other occurrence
node_modules/@substrate/smoldot-light/dist/mjs/instance/raw-instance.js
2: // Copyright (C) 2019-2022  Parity Technologies (UK) Ltd.
3: // SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
4: var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
                    ^
5:     function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
6:     return new (P || (P = Promise))(function (resolve, reject) {
...and 1 other occurrence
(!) Circular dependency
node_modules/@substrate/smoldot-light/dist/mjs/client.js -> node_modules/@substrate/smoldot-light/dist/mjs/instance/instance.js -> node_modules/@substrate/smoldot-light/dist/mjs/client.js

The this issue above seems to be caused by using await in the code and the build step, have not dug to see "why".

For the last issue in the log, the circular dep from client <-> instance, a solution could be -

• split all the classes extending Error into errors.ts
• import the specific error we need from errors.ts in instance.ts
• import/re-export the errors as required in client.ts

A suggestion, the team here would have their own ideas and know best. I just want to shine light on the above log.

[wirednkod]

Thank you @jacogr for this. I already started looking into it, so I hopefully will have a solution on these warnings soon

[tomaka]

For the __awaiter-related issue, I don't know much what we can do. This little var __awaiter block is automatically generated by TypeScript because we're targeting es6. None of the modules use await at the root level, only within function bodies.

[jacogr]

Looking at the Rollup error link, i.e. https://rollupjs.org/guide/en/#error-this-is-undefined - I would most-probably place that squarely on the rollup config where this is used to ensure it specifies a sane context. (At least in my bundle configs this is something I'm going to be doing - this is not the only library I found with something like)

[tomaka]

Closing, since the circular dependency has been addressed.