CB-14133 Avoid reinstalling already installed packages

[raphinesse]

This is to alleviate the performance penalty incurred by fetching-by-default.

This speeds up cordova prepare in below setup by about 200% (i.e. it takes half the time)

git clone https://github.com/dpogue/cb-13797
npm i
cordova prepare

• Only reuses packages if their version matches the requirements
• Still transparently supports all spec formats that npm install supports
• Obviously only works for specs that we can infer the package name (and maybe version) from. So git dependencies will still be fetched every time
• Includes a lot of refactoring too, which is kind of necessary for this change
• Modifies the tests so that they take less than half the time they used to

I'm sure there are other issues related to this, but I linked to the one that made me think of a robust and easy way to increase performance.

In the long run we should try to reduce all fetching to a minimum, but that has to be tackled in cordova-lib.

Future Work

• Add some way to prevent reusing installed packages?

[raphinesse]

You're too generous :bowing_man: Should we merge or let it sit for a while to wait for more reviews?

[dpogue]

It's probably easier for people to test if we merge and it gets into the nightly builds

[raphinesse]

Good point. I'd make this a real merge to keep diff readability. Are you fine with that?

[dpogue]

yep

[kirillgroshkov]

I'm just wondering - what are these binary files in the end of PR, e.g spec/support/repo-name-neq-plugin-id.git/refs/heads/master? Are they here by mistake or it's part of the plan?

[raphinesse]

@kirillgroshkov they are local test fixtures. To speed up a previously network-dependent test. See https://github.com/apache/cordova-fetch/commit/36ecb8c105dd6b2bc0c18f9abd30cc444150e8db

[kirillgroshkov]

@raphinesse Thanks for clarification:)