git-file-utils: add ways to invalidate cache entries

[dgellow]

Is your feature request related to a problem? Please describe.

Hey there 👋. git-file-utils is a nice simple package that does its job fairly well, but I find myself wishing it would offer a way to invalidate its cached data.

On a project I'm currently working on (heavily based on release-please, which is using git-file-utils as part of its github client) I faced multiple times the situation where I recreate a branch or heavily change its content/history but have no way to invalidate cached data without recreating the whole cache from scratch.

Describe the solution you'd like

Something like this would be perfect for my use case:

const fileCache: RepositoryFileCache;
const oldContent = fileCache.getFileContents("my-file.json", "branch-a");

await recreateBranch({branch: "branch-a", onTopOf: "branch-b"})

// whole branch can be invalidated (I know that RepositoryFileCache is currently only for a single branch, but I see this as an implementation detail)
fileCache.invalidateBranch("branch-a")

// or maybe just the file I want
fileCache.invalidateFile("my-file.json", "branch-a")

const newContent = fileCache.getFileContents("my-file.json", "branch-a");

Describe alternatives you've considered

• An alternative would be to pass a flag/option to the existing methods to bypass reading from the cache

Additional context

I think the context is fairly clear as it is, but I add provide more details if needed.

[chingor13]

This seems like a reasonable feature request, but is not something we immediately have a need to implement. Is this something you'd be interested in contributing? We would be happy to accept a PR for this.

Perhaps an new invalidateBranch(branch: string): BranchFileCache | undefined which would return the exisiting BranchFileCache that we are invalidating (if it exists).

[dgellow]

Nice, sounds good. I think I should have a bit of time this week to create a PR. But no guarantees :)