Add repositoryResolver option to mgit.json

[Reinmar]

In some configurations you may want to use a different resolver by default. It shouldn't be necessary to always pass it through CLI args.

[Reinmar]

Actually, let's make it a bit differently. This will be the default values:

  "resolver": {
    "path": "@mgit2/lib/default-repository-resolver.js",
    "urlTemplate": "git@github.com:${ path }.git",
    "include": "*",
    "useLongPaths": false,
    "defaultBranch": "master"
  }

And each of these options will have a CLI alternative:

--resolver-path
--resolver-urlTemplate
--resolver-include
--resolver-useLongPaths
--resolver-defaultBranch

[Reinmar]

I proposed two more options – include which will be needed for recursive cloning (currently, we handle this by a custom resolver (https://github.com/ckeditor/ckeditor5-dev/blob/c7fc65cd9f795255dee0bccc83a0b8cf3915af86/packages/ckeditor5-dev-tests/lib/git-https-resolver.js#L25) and defaultBranch which may be needed in the future.

[Reinmar]

The proposed options:

    Options:
        --fetch                     Whether to fetch changes from remote repositories.
                                    Default: true.

        --recursive                 Whether to install dependencies recursively.
                                    Needs to be used together with --repository-include. Only packages
                                    matching these patterns will be cloned recursively.
                                    Default: false.

        --resolver-path             Path to a custom repository resolver function.
                                    Default: '@mgit2/lib/default-repository-resolver.js'.

        --resolver-urlTemplate      Template used to generate repository URL out of a
                                    simplified 'organization/repository' format of the dependencies option.
                                    Default: 'git@github.com:${ path }.git'.

        --resolver-include          Comma separate minimatch patterns of packages which can be cloned recursively.
                                    Needs to be used together with '--recursive'.
                                    mgit gets dependencies and devDependencies of cloned package from its
                                    'package.json' and clones those which match the specified patterns.

        --resolver-useLongPaths     Applies to scoped npm packages.
                                    If true, the package will be cloned to: 'packages/@scope/pkgname'.
                                    If false, to 'packages/pkgname'.
                                    Default: false

        --resolver-defaultBranch    The branch name to use if not specified in mgit.json dependencies.
                                    Default: 'master'

[pomek]

To be consistent with CLI standard:

--resolver-urlTemplate => --resolver-url-template

Etc.

[pomek]

And remember about update the README file.

[Reinmar]

Turns out that --resolver-include can't be implemented this way. It's not about which packages to include, but how to generate their URL. A simple pattern matching won't do that.

[Reinmar]

OK, so if I haven't missed anything, the default resolver will look like this:

'use strict';

const parseRepositoryUrl = require( './utils/parserepositoryurl' );

/**
 * Resolves repository URL for a given package name.
 *
 * @param {String} name Package name.
 * @param {Object} options TODO
 * @returns {Repository|null}
 */
module.exports = function repositoryResolver( name, options ) {
	let repositoryUrl = options.dependencies[ name ];

	if ( !repositoryUrl ) {
		return null;
	}

	return parseRepositoryUrl( repositoryUrl, options );
};

The options object is, for simplicty, exactly the same as the options passed to CLI. This way the function is maximally short and hence, can be easilly extended by anyone.