Mitigate out of free space issues while running dartdoc postprocessing.

[isoos]

• Package analysis is not starting (pending) and says no log #7981
• By deleting the input dartdoc data, the post-processing in both isolates will stop.
• We are deleting the partial output as we won't use it, and we may need free space to complete writing the log.txt and the blob files.

[jonasfj]

I don't understand this.

Who owns the docDir, I think we should say that it's owned by the caller to postProcessDartdoc as is currently the case.

And that postProcessDartdoc only read from docDir.

It feels messy to be sometimes deleting it here and sometimes not.
If we want to delete it here, we should always do so, and we should document it for the caller.

However, I see no reason to do that.

---

Here we're trying to stop the isolates from running by deleting their input files.
I think that's a bit wild. Perhaps it'd be more reasonable to:

• (A) Not run the two thing concurrently, so we don't have to use isolates.
• (B) Create a runInIsolate<T>(FutureOr<T> Function() computation, {Completer<void> cancel}).

Obviously, (B) would require that we create a tiny helper library for running stuff in an isolate with cancellation. And that we have tests 🤣

I think the correct approach for what you're trying to do is (B), but that the simply solution is (A). Afterall, it's fairly likely that both these operations are going to be I/O bound (maybe not post-processing).

[isoos]

Fixed the docDir deletion. Agreed on (B) being the better one, but for a simple handling we may just do the cleanup.

[jonasfj]

At a minimum we should exit non-zero here, right?

[jonasfj]

or rethrow?