Summary:
See https://github.com/facebook/react-native/issues/14423
This adds checks after download that each file is present, and has the
correct sha1 hash. If not, it will retry several times, and fail if
it can't successfully download the file. If a file is downloaded, the
unpack and command will run, even if the third-party dir already
exists. The diagnostics printed in the event of failure are improved.
This should be self-healing for anybody who has a bad ~/.rncache
directory. The checksum will fail, and the files will be
redownloaded.
Reviewed By: hramos
Differential Revision: D5930707
fbshipit-source-id: cb15af949294243448ccc3995ec3f0396b1922b6