[rush] Rush init should use newer versions?

[halfnibble]

Please prefix the issue title with the project name i.e. [rush], [api-extractor] etc.

Is this a feature or a bug?

• Feature

Please describe the actual behavior.
Running rush init will create a rush.json file with presently installed version of rush and pnpm version 2.15.1.

If the issue is a bug, how can we reproduce it? Please provide detailed steps and include a GitHub branch if applicable. Your issue will get resolved faster if you can make it easy to investigate.

rush init

What is the expected behavior?
Should this create a new rush project with the latest available version of rush? Or does it make sense to use the currently installed version?

Also, should we update this template to use a newer version on pnpm?

After further discussion, we should do the following:

• Print a warning in the console if the version of rush being used to generate a new project with rush init is not the latest version.
• Update the pnpm version to the latest tested version in the rush init template.
• Add .DS_Store to .gitignore in the rush init template.
• Anything else...?

[octogonz]

Here's one more issue:

If you run rush init --overwrite-existing in an existing Rush folder, it will use the version from rush.json even if a newer version is installed globally. The main point of that feature is for upgrading a repo, so the behavior is super annoying and certainly a bug.

So I'd propose the following

• rush init prints an error (not warning) if it's not the latest Rush.
• The error should instruct the person to run npm install -g @microsoft/rush if they want the latest version.
• If the person really wants an older Rush, or if they don't have an internet connection, we should provide an option (e.g. --skip-version-check) that suppresses the rush init error
• Upgrade PNPM to a hardcoded known good recent version. (I don't think we should autodetect this version, since some releases are more stable than others.)
• We should also update the Yarn version, but not NPM. (4.5.0 is actually the latest known good version for NPM.)
• Add .DS_Store to .gitignore in the rush init template. 👍
• To address my issue above, rush init should bypass the version selector and use the globally installed Rush. This is slightly tricky because you have to safely parse the init token in rush/src/start.ts. But it is the right thing to do. (Ping me on Gitter for help with this.)

[octogonz]

In this Gitter conversation we discussed introducing a new binary myrush that invokes your globally installed Rush version (bypassing the version selector that would normally invoke the version specified in rush.json).

With this feature, you could use myrush init --overwrite-existing to upgrade a repo to your locally installed version of Rush.

[octogonz]

Issue #1073 pointed out that the error message The "rush init" command must be run in a new folder without an existing Rush configuration. could be more helpful -- in its current form it's not obvious to users how they are supposed to upgrade their repo. We should tackle these problems together.

I apologize for the lack of progress on PR #1771. I'll see if I can make some time to push it along. This is a core user scenario we're trying to improve, and (hopefully) a relatively easy fix.