So, if I understand this, broccoli sometimes changes the inputPath for us, and we need to be able to propagate that change to the TreeDiffer, and we do that here by passing it in here, right?

But, (some) plugins still think they need to use the old inputPath, they don't have any idea that it changed

looks like it to me. my patch is failing in some cases so I need to investigate it further. initial explorations showed that the output path for certain plugins like replace and mergeTrees was not immutable.

Have you thought about something like this?

class DiffingPluginWrapper {
  get inputPath() { return this._inputPath; }
  set inputPath(path) {
    this._inputPath = path;
    // propagate the change to wrapped plugin
    if (this.initialized) this.wrappedPlugin.inputPath = path;
  }
  // etc
}

https://github.com/IgorMinar/angular/pull/1/files working example (tested with test.unit.tools and test.unit.cjs)

I did think about that, but it is simply wrong that the input path changes. The plugin should be the owner of the inputPath state and nobody else should change it, otherwise the whole system is unstable and it's easy to make assumptions that the input path doesn't change and cache absolute paths somewhere.

I have a different PR in works that stabilizes the input path.

The contracts for these properties are pseudo-documented in the broccolijs codebase, but it's not clear how strong those contracts are.

There's a problem here: fingerprints still contain old absolute paths, so fingerprints basically need a reset (or alternatively, the fingerprints object keys need to be the relative path rather than absolute)

it should be a relative path

For posteriority: I must have had a subtle error when trying the relativePath stuff before, it seems to work correctly now (so virtualPath is not needed) --- updating the pr