Gatsby not working after yarn install

[matchatype]

Description

Having a pretty weird issue. My Gatsby app used to run just fine. Today I updated to v2.20.26 using yarn as usual. From that point on, running any command, like gatsby develop returned me this error:

 ERROR 

There was a problem loading the local develop command. Gatsby may not be installed. Perhaps you need to run "npm install"? Cannot find module 'date-fns/getDayOfYear'

I tried gatsby clean , rm -rf node_modules, even rolling back to a previously working app... nothing... Always triggering that error. Then I tried npm install and that's working.

So, after a couple of tests, I noticed that if I clean node_modules and use npm install, everything works. With yarn install it doesn't. Tried also removing package-lock.json and yarn.lock. Nothing seems to help yarn.

If I install via npm and then run any command with yarn, it will work just fine. So apparently there's an issue with yarn install. I'm running yarn v1.22.4 and always worked fine till today.

I tried comparing the contents of the node_modules directory using both package managers (with no lock files) and they actually differ.

[herecydev]

What are the differences you see?

[matchatype]

Pretty much every dependency folder has different size, but the most notable issue is that gatsby-cli is completely missing in npm's node_modules directory.

[herecydev]

What version of yarn are you using?

[matchatype]

yarn v1.22.4
npm v6.13.4
node v12.16.1

[matchatype]

What worked in my case was cleaning my cache with yarn cache clean. I read about rather similar issues of people having similar mysterious problems, however with npm rather than yarn, and nobody tried this. Npm has similar feature npm cache clean.

[a-maccormack]

I checked documentation (https://classic.yarnpkg.com/en/docs/cli/global),
and this is what ended up working for me on Linux (pop-os 21.10):

Add the following line to ~/.bashrc or ~/.zshrc (depending on what you use)

export PATH="$HOME/.yarn/bin:$PATH"

And you're done.

If this doesn't work for you, you can search for your yarn bin directory with the following command:

yarn global bin

Then replace (yarn bin path) on ~/.bashrc or ~/.zshrc with the path you got by using the command above

export PATH="$(yarn bin path):$PATH"

Hope this helps anyone struggling to solve this