[magicalhippo]

Reminded me of the Restate idea[1], discussed here[2] recently, except they do it as a library. An excerpt:

To persist intermediate steps (line 8), handlers use the SDK (ctx.run), which sends the event to the log and awaits the ack of the conditional append to the event’s execution journal. On retries, the SDK checks the journal whether the step’s event already exists and restores the result from there directly.

Though I think I agree with your point that it would be better to have this even more integrated than "just" a library. Perhaps something like how you can override the global memory allocator in C and similar languages, to avoid a tight coupling to the persistence layer.

[1]: https://restate.dev/blog/every-system-is-a-log-avoiding-coor...

[2]: https://news.ycombinator.com/item?id=42813049