step.store_required: An action makes several changing calls but writes no database, and the app names no database to keep the record of its calls in

An action makes several changing calls but writes no database, and the app names no database to keep the record of its calls in.

Area 12, Background work; not declinable; the next step is usually the human's.

Why Jadpo refuses it

A changing call, such as a provider operation with changes: true or a store's put, takes effect as soon as it is made. When an action makes several, Jadpo records each one before it goes out and its answer when it comes, so a retry replays the answered calls instead of sending them again. That record is kept in a database, beside the outbox of the one the action writes. An action that writes none has nowhere to keep it, and Jadpo won't choose a database for it: events: { store: } names the one.

What it looks like

domains/bakery/actions/file_prices.jadpo, in a bakery app whose only connection is sheets, a folder of files:

example

use app { sheets }use bakery/failures { SheetNotKept }use bakery/events { PricesChanged }/// Keeps a supplier's new prices as a sheet, then a copy for the/// accountant.action file_prices(event: PricesChanged) fails SheetNotKept -> Unit {    var sheet: File = attempt sheets.put(encoding.to_utf8(event.price_list), FileType.csv) {        storage_full: SheetNotKept    }    var invoice_copy: File = attempt sheets.put(encoding.to_utf8(event.price_list), FileType.csv) {        storage_full: SheetNotKept    }    assert sheet != invoice_copy}

jadpo checkcheck failed: 1 error, 7 files

error file_prices makes 2 changing calls but writes no store to keep their record in

--> domains/bakery/actions/file_prices.jadpo:8:31

  |8 |     var sheet: File = attempt sheets.put(encoding.to_utf8(event.price_list), FileType.csv) {  |                               ^^^^^^^^^^ no store for the record

reason: Each changing call is recorded before it goes out, beside the outbox of the store its action writes, so a retry can replay it; file_prices writes no store, itself or through what it calls, and app.jadpo names none with events: { store: }.
next: Add events: { store: main } to application { } in app.jadpo (human)
rule: step.store_required
help: https://jadpo.dev/docs/errors/step.store_required

(human) at the end of the next: line tells your coding agent to stop and ask you which fix you want, because the choice is yours to make: it decides which database keeps the record of these calls, and the events of every action that writes none.

How to fix it

If a database should keep the record, connect it and name it in events: { store: } in app.jadpo, with its address as a setting in config.jadpo. Here the database is a new one, main:

example

        main: {            driver: Driver.postgres            url: config.main_url        }    events: {        store: main    }

Each of file_prices's two sheets.put calls is now recorded in main before it goes out, and its answer after it. When the delivery is tried again, the answered calls are replayed rather than sent again, and the record is deleted when the action commits.

An action that writes a database keeps its record in that one instead, so it never needs events: { store: }.

Why Jadpo refuses it

What it looks like

How to fix it

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