feat!: adopt unthrown v5 (beta)

[btravers]

Adopts unthrown 5.0.0-beta.3 across the fixed version group. On merge this publishes 8.0.0-beta.0 (major; the two pre-existing patch changesets fold in).

Note

Green and ready — no known follow-ups. unthrown 5.0.0-beta.3 fixes both v5 inference regressions this branch had hit: the async-flatMap collapse (fixed in beta.2) and the covariance-widening regression (fixed in beta.3). All 9 explicit-type-arg workarounds in client.ts are removed; every gate step passes (see below).

What changed

• Beta pre-mode: changeset pre enter beta (adds .changeset/pre.json).
• Version bump (catalog): unthrown and @unthrown/vitest 4.1.0 → 5.0.0-beta.3; peer unthrown ^4.1.0 → ^5.0.0-beta.3 in client / worker / contract. (unthrown + @unthrown/vitest were already in minimumReleaseAgeExclude, so the strict supply-chain install passed with no change there.)
• API migration to v5's ts-pattern matcher callbacks:
  • Error combinators — flatMapErr (1: client interceptor retry test) and tapErr (1: activity middleware test) → (matcher) => matcher.with(P._, ...).
  • match's err handler (real code) — worker.createWorkerOrThrow, activity fold, plus 2 client specs → (matcher) => matcher.with(P._, ...).
  • matchTags (removed in v5) → result.match({ err: (m) => m.with(tag(...), ...) }) in the order-processing-client example (2 folds, 6 tags each, kept exhaustive).
  • TSDoc @example blocks + prose across client.ts / worker (workflow, activity, cancellation, errors) updated to the matcher form.
• qualify (part C): audited all fromPromise sites — all qualifiers already synchronous, no change. No async tapErr branches. No unwrap* / orElse / recover / UnwrapError usage.
• Covariance workarounds removed (beta.3): the 9 explicit-type-arg returns (Err<Err>(...) / Err<ProxyError>(...)) added on beta.2 are reverted to plain Err(...) — a concrete Err now widens into the generic error union.

Gate status (on 5.0.0-beta.3)

step	result
pnpm format --check	✅
pnpm lint	✅
pnpm typecheck	✅ (12/12 tasks, no explicit-type-arg workarounds)
pnpm knip	✅
pnpm test	✅ (354 tests across 27 files)
pnpm build	✅ (incl. docs)

Regressions hit and resolved upstream

• Async flatMap inference collapse — an AsyncResult-returning callback collapsed the success type to unknown. Fixed in 5.0.0-beta.2; the sample-order-processing-client example typechecks with no workaround.
• Covariance widening — a concrete Err(...) return failed to widen into a generic error union (a generic-conditional E union defeated the declared out E fast path, forcing structural comparison into the invariant ts-pattern Match). Fixed in 5.0.0-beta.3; the 9 explicit type args are removed and typecheck stays green.

No known follow-ups remain.

Merge

Ready for review. On merge it publishes 8.0.0-beta.0.

[Copilot]

Pull request overview

This PR migrates the repo’s fixed version group to unthrown v5.0.0-beta.2, updating code and documentation to the new v5 matcher-callback APIs (ts-pattern-based) and entering Changesets beta pre-mode to publish the next prerelease line.

Changes:

• Bump unthrown and @unthrown/vitest to 5.0.0-beta.2 via the workspace catalog (and lockfile regeneration).
• Migrate match/tapErr/flatMapErr usage to v5’s (matcher) => matcher.with(...) callback style across worker/client code, tests, and docs.
• Add prerelease configuration (.changeset/pre.json) and a major changeset for the v5 migration.

Reviewed changes

Copilot reviewed 19 out of 20 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
pnpm-workspace.yaml	Updates catalog versions for unthrown + @unthrown/vitest to v5 beta.2.
pnpm-lock.yaml	Lockfile updates reflecting unthrown v5 beta.2 and new transitive deps (e.g., ts-pattern).
packages/worker/src/workflow.ts	Updates TSDoc examples to v5 matcher-callback err handler form.
packages/worker/src/worker.ts	Updates createWorkerOrThrow match err branch to v5 matcher callback and imports P.
packages/worker/src/errors.ts	Updates documentation prose to refer to result.match/ts-pattern matching instead of removed matchTags.
packages/worker/src/cancellation.ts	Updates TSDoc example err handler to v5 matcher callback form.
packages/worker/src/activity.ts	Updates middleware example (tapErr) and activity result folding err handling to matcher callback form; imports P.
packages/worker/src/activity-contract-errors.spec.ts	Updates tests to v5 tapErr matcher-callback style and imports P.
packages/worker/package.json	Bumps unthrown dependency range to ^5.0.0-beta.2.
packages/contract/src/errors.ts	Updates docs describing discrimination approach to use result.match(... tag(...)) instead of matchTags.
packages/contract/src/errors.spec.ts	Updates test description wording to reflect match/tag-style discrimination.
packages/contract/package.json	Bumps unthrown peer dependency range to ^5.0.0-beta.2.
packages/client/src/interceptors.ts	Updates interceptor example (flatMapErr) to matcher callback form.
packages/client/src/client.ts	Updates TSDoc examples to matcher-callback form; applies explicit Err<...> typing workaround in a few returns.
packages/client/src/client.spec.ts	Updates unit tests to matcher-callback err handler form and imports P.
packages/client/src/tests/client.spec.ts	Updates integration test match err handler to matcher-callback form and imports P.
packages/client/package.json	Bumps unthrown peer dependency range to ^5.0.0-beta.2.
examples/order-processing-client/src/client.ts	Migrates from matchTags to result.match({ err: (m) => m.with(tag(...), ...) }).
.changeset/pre.json	Enters Changesets prerelease mode with beta tag.
.changeset/adopt-unthrown-v5-beta.md	Adds a major changeset describing the breaking migration to unthrown v5 beta.

Files not reviewed (1)

• pnpm-lock.yaml: Generated file