feat(yarn): support yarn offline mirror

[rarkins]

Look for .yarnrc in same directory as yarn.lock. If found, look for yarn-offine-mirror line and check that folder for changes.

Closes #1452

[renovate-bot]

🎉 This PR is included in version 19.2.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀

[mrtnzlml]

@rarkins Hi, this still doesn't work for us. But I have a hard time to figure out what is wrong. This is the log from our CI:

$ yarn install --offline --frozen-lockfile
yarn install v1.17.3
[1/5] Validating package.json...
[2/5] Resolving packages...
[3/5] Fetching packages...
error Can't make a request in offline mode ("https://registry.yarnpkg.com/flow-bin/-/flow-bin-0.103.0.tgz")
info Visit https://yarnpkg.com/en/docs/cli/install for documentation about this command.

BUT this MR contains the .tgz archive, updated yarn.lock and all relevant package.json files. I tried to checkout this MR and install it locally which indeed does something and at the end the archive is modified but git diff is not helping me very much:

diff --git a/.yarn/cache/flow-bin-0.103.0.tgz b/.yarn/cache/flow-bin-0.103.0.tgz
index 1a637c55..34828197 100644
Binary files a/.yarn/cache/flow-bin-0.103.0.tgz and b/.yarn/cache/flow-bin-0.103.0.tgz differ
(END)

Do you have any idea what is wrong? Every MR from renovatebot fails like this. 🤔

[mrtnzlml]

Mm, one more clue maybe: I returned back to master and deleted the branch to continue working on something else. Then I returned back, checked out the MR again and there was no problem suddenly (yarn install was happy). So I deleted local Yarn cache (yarn cache clean) and tried again. This time I got this error:

yarn install v1.17.3
[1/5] 🔍  Validating package.json...
[2/5] 🔍  Resolving packages...
[3/5] 🚚  Fetching packages...
error https://registry.yarnpkg.com/flow-bin/-/flow-bin-0.103.0.tgz: Integrity check failed for "flow-bin" (computed integrity doesn't match our records, got "sha512-kTWKyK819ZuRxHBrkfup49QcMHvmIay8zgjph9e30/Xb49mcNUyQm+VLKipSeh6lWZsJ1S/F4jwJx8CwP9ZY6w==")

Something is definitely not OK with these MRs. Thanks for having a look.

[rarkins]

Created new issue #4126 to track in