Cache feature does not work

Describe the bug Running betterer with --cache flag multiple times does not actually make anything calculate faster. Despite code not being changed, all comands run and for example recompile Typescript.

To Reproduce If possible please share a repo with the issue, or another repository which demonstrates the issue. If possible please include the .betterer.ts file, and the .betterer.results file if applicable. At a minimum please share the command you are using to run Betterer.

Expected behavior Running command twice with --cache flag makes second run instant.

Screenshots

Versions (please complete the following information):

System:

• OS: macOS 11.6
• Memory: 35.78 MB / 16.00 GB

Binaries:

• Node: 16.13.0 - ~/.nvm/versions/node/v16.13.0/bin/node
• Yarn: 1.22.17 - /usr/local/bin/yarn
• npm: 8.1.0 - ~/.nvm/versions/node/v16.13.0/bin/npm

Languages:

• Bash: 3.2.57 - /bin/bash

Betterer:

• 5.0.0-alpha.0

Debug log:

[Giesch]

If it was a problem with betterer’s file caching, I think it would be either:

1. A change to an export in file A causes the cached file B to no longer compile, but B’s cache wasn’t busted, or
2. Changing between branches didn’t clear the cache, so incorrect data was in the cache

But the more likely explanation in our case is that code that didn’t pass the betterer ci check made it into master.

As far as caching goes, it was definitely faster; tsc might be able to more reliably address 1 & 2 above, or betterer might be addressing them well enough, I don’t know. My only guess would be that 1 is trickier than it looks because it can involve type inference as well as exports/imports. Like, a change to a type can break files that import related functions but don’t import the type itself. But the fact that we had a problem does not mean that 1 or 2 was the problem.

[jimmy-guzman]

Not sure if this is related but were facing something similar with betterer cache when changing branches. If we change to a new branch sometimes betterer cache fails with errors that seem like some types are missing from external libs.

Deleting the cache or bypassing the cache results in no errors.

We ended up not using the cache for typescript for now.