Cannot update pnpm after downgrade

[pitgrap]

I updated to pnpm 8.6.1 and used it in a workspace. Everything worked.
After that, I had to downgrade to 8.5.1 for an older project (pnpm i -g pnpm@8.5.1). Everything worked.

Now I want to go back to 8.6.1 but I get the following error:

❯ pnpm i -g pnpm@8.5.1
 WARN  Your pnpm-lock.yaml was generated by a newer version of pnpm. It is a compatible version but it might get downgraded to version 6.0
.pnpm                                    |  WARN  Your pnpm-lock.yaml was generated by a newer version of pnpm. It is a compatible version but it might get downgraded to version 6.0
 ERROR  /@aws-amplify/cli@9.1.0 is an invalid relative dependency path

How can I update my pnpm version without deleting the store?
Instead of deleting the store just remove the lock.yaml in ~/.local/share/pnpm/global/5/.pnpm and the pnpm-lock.yaml in ~/.local/share/pnpm/global/5

Please, please change the major version everytime something changes in the lock file in the future to avoid this breaking changes.

pnpm version:

8.6.1

Code to reproduce the issue:

pnpm i -g pnpm@8.6.1 
#install something globally like pnpm i -g @aws-amplify/cli or install deps in any workspace
pnpm i -g pnpm@8.5.1
pnpm i -g pnpm@8.6.1

Expected behavior:

It works.

Actual behavior:

It doesn't work and can't update pnpm.

Additional information:

• node -v prints: v18.16.0
• Windows, macOS, or Linux?: Linux (WSL)

[zkochan]

It is caused by this issue: #6648

I will fix it. To fix the update issue you may either manually change the lockfile version to 6.0 in the global directory's lockfile. Or install pnpm using the standalone script: https://pnpm.io/installation#using-a-standalone-script

[zkochan]

This won't be a problem anymore. I have deprecated the non-backward compatible versions of pnpm. But if it did happen to you, you can try what I suggested above. Or you can uninstall pnpm: https://pnpm.io/uninstall
and then install it again.