feat: optionally execute 'git push' during the publish phase

[jfairley]

This is optionally configurable through a new property called 'pushStep', which defaults to 'prepare', but accepts input as 'prepare' or 'publish'.

@pvdlg I intended to write a test to verify that push was called at the correct times, but I'm new to ava, and I didn't see an existing precedent on how to assert that "push" was called. I'll gladly add another test if you could nudge me in the right direction.

[jfairley]

@pvdlg You know, the more I think about this, the more I realize how useful it would be for my maven workflow to have the whole cycle run on "prepare" and "publish".

The actual JS changes would actually be more elegant, since:

1. prepare.js could remain completely unchanged, except it'd be appropriate to rename it.
2. In index.js I could add an async function publish looking much like async function prepare.
3. Both function prepare and function publish would check the value of context.commitAndPushSteps (see examples below), which would default to 'prepare' for backwards compatibility.

Here's what I'm thinking as far as configuration could look:

module.exports = {
	plugins: [
		// prepare: bump maven version to `nextRelease.version`
		// publish: 1. build and deploy artifacts
        // publish: 2. bump maven version to the next snapshot version
		'semantic-release-maven',
		['@semantic-release/git', {
			assets: ['pom.xml'],
			// this is optional and defaults to 'prepare' (preserving backwards compatibility)
			commitAndPushSteps: ['prepare', 'publish']
		}]
	]
};

The only thing I'm stuck on with ^^^ solution is reusing the same message...

So, here I have a semantic-release question: Is the context mutable and shared between plugins? What if in my custom plugin I set context.mavenVersion = '1.2.3'? That could allow something like:

module.exports = {
	plugins: [
		'semantic-release-maven',
		['@semantic-release/git', {
			assets: ['pom.xml'],
			message: 'chore(release): ${mavenVersion} [skip ci]',
			commitAndPushSteps: ['prepare', 'publish']
		}]
	]
};

Or something else I've been chewing on is declaring the git plugin twice, but again, is this possible? If so I could do something like:

module.exports = {
	plugins: [
		['@semantic-release/git', {
			assets: ['pom.xml'],
			commitAndPushSteps: ['prepare']
		}],
		'semantic-release-maven',
		['@semantic-release/git', {
			assets: ['pom.xml'],
			message: 'chore(release): incrementing to next development snapshot [skip ci]',
			commitAndPushSteps: ['publish']
		}]
	]
};

---

If any of this is confusing, I'll gladly push up a separate PR to illustrate the code changes... In fact, I might do it anyway, since the changes ought to be pretty easy...

[jfairley]

And yet another hair-brained configuration idea...

module.exports = {
	plugins: [
		'semantic-release-maven',
		['@semantic-release/git', {
			prepare: {
				assets: ['pom.xml']
			},
			publish: {
				assets: ['pom.xml'],
				message: 'chore(release): incrementing to next development snapshot [skip ci]'
			}
		}]
	]
};

Obviously, even in this scenario, doing the standard configuration, would apply the data to "prepare", and "publish" would not happen unless specified. ⬇️

module.exports = {
	plugins: [
		// ... a bunch of standard plugins,
		['@semantic-release/git', {
			assets: ['package.json', 'package-lock.json']
		}]
	]
};

[jfairley]

I closed this for clarity. I prefer and put more work into #122.