Why did package-lock.json change the integrity hash from sha1 to sha512?

Question

From what I can see, npm changed the integrity checksum from sha1 to sha512.

If your git changes are going from sha1 to sha512, you should do that update once and it will be good after that.

If someone else working with the codebase and sees a git change from sha512 down to sha1 (which is the issue I was having) you can fix it by running the following:

Discard the changes in git for package-lock.json

npm i -g npm
rm -rf node_modules/
npm i

This will update npm and reinstall all of your packages so that the new checksum (sha512) is present.

Building on what Dave answered. The fix i found was to do the following:

npm i -g npm

cd {working directory}
rm -rf node_modules/
rm package-lock.json
npm cache clear --force
npm i

We did this for all our developers at the same time and this stopped the sha-512 vs sha-1 issue which was causing frustrating merge conflicts.

See also https://github.com/npm/npm/issues/17749 which although claims the issue is 'fixed', it isn't. Removing node_modules is a workaround.

There may be a relationship with operating systems. We're hitting this right now with developers on Linux and Windows platforms.

As @Daniel Cumings I also had to remove the package-lock.json to get rid of the sha1 hashes. Here's the Windows CLI commands for reference, which does the same as Daniel's script:

npm i -g npm
rd /s /q "node_modules"
del package-lock.json
npm cache clear --force
npm i

I'm working in big team. Forcing every developer to force clean npm cache is difficult and not reliable. Also, this doesn't help every time. So, for anyone who still facing this npm issue (same as me) and nothing else helps – try this git based tool I've built recently: https://github.com/kopach/lockfix. It reverts sha512 -> sha1 integrity changes of npm's lock files. If you add this to your postshrinkwrap script of package.json - you should eventually get all integrity properties set to sha512 and have lock file consistent.

npm install --save-dev lockfix

"scripts": {
    "postshrinkwrap": "lockfix",
},