Switched development environment to Yarn

[pomek]

Suggested merge commit message (convention)

Other: Switched development environment to Yarn. Closes #1214.

---

Additional information

• CI for all packages will fail because it requires changes from Use Yarn on Travis ckeditor5-dev#453.
• Build that confirms that changes work: https://travis-ci.org/ckeditor/ckeditor5-table/builds/451805447
• All packages (except the builds) contain a branch ckeditor5/t/1214 that contains changes for ckeditor5-* packages (https://github.com/ckeditor/ckeditor5-font/compare/ckeditor5/t/1214)

Side note: Indentations in .travis.yml have changed once again because I used mgit and a script (specified below) for modifying the configuration file.

#!/usr/bin/env node

const path = require( 'path' );
const fs = require( 'fs' );
const cwd = process.cwd();
const configPath = path.join( cwd, '.travis.yml' );

if ( !fs.existsSync( configPath ) ) {
	return;
}

// https://www.npmjs.com/package/js-yaml
const YAML = require( 'js-yaml' );
const config = YAML.load( fs.readFileSync( configPath, 'utf-8' ) );

config.sudo = 'required';

config.dist = 'trusty';

config.addons = {
	firefox: 'latest',
	apt: {
		sources: [ 'google-chrome' ],
		packages: [ 'google-chrome-stable' ]
	}
};

config.language = 'node_js';

config.node_js = [ '8' ];

config.cache = { yarn: true };

config.branches = {
	except: [ 'stable' ]
};

config.before_install = [
	'export DISPLAY=:99.0',
	'sh -e /etc/init.d/xvfb start',
	'npm i -g yarn'
];

config.install = [
	'yarn add @ckeditor/ckeditor5-dev-tests',
	'ckeditor5-dev-tests-install-dependencies'
];

config.script = [ 'ckeditor5-dev-tests-travis' ];
config.after_success = [ 'ckeditor5-dev-tests-save-revision' ];

fs.writeFileSync( configPath, YAML.safeDump( config, { flowLevel: -1, lineWidth: 10000} ), 'utf8' );

[Reinmar]

Why did it change yarn.lock?

I don't understand yet how and when yarn.lock should be updated. But I assume that calling yarn install shouldn't cause that. Am I right?

cc @ma2ciek

[Reinmar]

Is there a chance that changes in package.json (merged from master) caused this? I can see that the committed version of deps are old:

[Reinmar]

Can it be like this?

Suggested change

	- yarn run test --reporter=dots
	- yarn test --reporter=dots

[ma2ciek]

yarn allows to do it. But IMO it might be risky to do it in .travis file.

[ma2ciek]

Changing the package.json or calling yarn upgrade may change the yarn.lock. Calling yarn install shouldn't change.

[Reinmar]

Also no need to run.

[Reinmar]

Actually, I made a couple of suggestions here in this PR, but it'll be easier to change this automatically in all places. s/yarn run/yarn seems to work for me.

[Reinmar]

Suggested change

	yarn run test --files=core
	yarn test --files=core

[Reinmar]

Suggested change

	yarn run test --watch --coverage --source-map --files=engine
	yarn test --watch --coverage --source-map --files=engine

[ma2ciek]

IMO using yarn <our command> is risky as we don't know if yarn won't introduce its own command under the same name in the future.

[pomek]

This is a reason why I propose using yarn run ...

[pomek]

Task ends with the error code but there was no error. But maybe it should be reported to Yarn.

[Reinmar]

OK, good points.

[Reinmar]

I miss the old good lerna clean task. Can you add yarn run clean which would do the same thing?

I think that it will boil down to executing:

rm -rf node_modules && mgit exec 'rm -rf node_modules'

[pomek]

Sounds good.

[Reinmar]

Also, we need to update this in package.json:

    "reset": "rm -rf ./packages ./node_modules && mgit bootstrap && lerna bootstrap",
    "reinstall": "lerna clean --yes && lerna bootstrap",

[Reinmar]

I left 2 minor comments in https://github.com/ckeditor/ckeditor5-dev/pull/453/files

Other than that, I'd love if we could return to the previous .travis.yml formatting. Otherwise, if we'd use travis encrypt in new packages (or existing ones) the formatting will differ.

[pomek]

Other than that, I'd love if we could return to the previous .travis.yml formatting.

Done.