Handoff value the next step rejects

What goes wrong

A step emits a value in a form the following step will not accept, so the work stops partway with no route onward. Each side is self-consistent and was exercised on its own, and the author relies on whatever one step produces being usable by whatever reads it next.

Example

The export step writes an entry of a kind the import step refuses to read, so every transfer that includes one stops at the same point.

Not to be confused with

Not Two ends disagree on valid forms, where the two sides overlap and only unusual inputs diverge; here the handed-over value is refused on every ordinary run.

Discovered by

@sks24git GitHub

Field notes · 7

@sks24git2026-11-07beat 1 review round

The server stopped one action for a kind of record, but the page still showed its buttons and the handler checked a credential first. Users kept clicking a dead button and were told to renew a key that could never help.

Remove a rule's buttons when you add the rule. A refusal the page still offers is a dead end.
Answer the real refusal before any other check. An earlier check hides why it failed.

@sks24git2026-11-07

A fix let a script step carry on past a failed lookup, but a later search over that now-empty result also fails. Under stop-on-error that search ends the step, so the new alert is still never written.

Follow an empty value to every line that reads it. Letting one failure through moves the crash to the next reader.

@sks24git2026-11-04beat 2 review rounds

A page mode that only our own pages understand was copied into links to a separate app at click time. The app does not know the value, so a visitor in that mode lands in the wrong flow after sign-in.

Map local values at the boundary. An outbound link carries only values its target accepts; test it by clicking it.

@sks24git2026-11-02beat 3 review rounds

A question template quietly adds a default dont-know button to every question, and a new summary message reuses that template. The client sees a button the server then rejects, and nothing happens when they press it.

List the buttons a message really sends in its test. Defaults added by a shared loader hide from the author.

@sks24git2026-10-26

A log reader takes an id, and the new caller handed it the whole job record. The fetch fails quietly, the fallback finds no path, and the step meant to file fixes always concludes there is nothing to fix.

Fake the exact argument, not the call. A double that ignores its input hides a wrong one.
Copy the existing caller's argument at a new call site. Same name, different shape, is the trap.

@sks24git2026-10-15beat 1 review round

A generated task names a fallback file for a required check, and the fallback picks a test file. The tool that runs the check refuses test files, so every generated task demands a step nobody can perform.

Feed a fallback to its real consumer in a test. A default the tool rejects dead-ends every task.
Write 'unknown' over a plausible guess. A wrong hint misleads more than a blank.

@sks24git2026-10-11beat 4 review rounds

A tool rebuilt a commit range by reverse-applying a diff, but the diff held a binary file with no patch data. Any change that touches an image fails before the work starts and logs a missing-output error instead.

Check every input shape a rebuild step can't handle, before it runs. A binary or submodule entry needs its own named refusal, not a generic downstream error.