fix(schema): accept null dateReceived and nullish generic occurrence

[tossp]

Summary

Accept nullable date fields in EventSchema responses that are valid according to the Sentry API contract.

Problem

On a self-hosted Sentry instance, the event API returned this payload:

{"id":"2d9a3f30ee5a4a95b712e78b87631f9a","eventID":"2d9a3f30ee5a4a95b712e78b87631f9a","type":"default","dateReceived":null,"occurrence":null}

EventSchema.parse then raised an invalid_union Zod error. In particular, the dateReceived branch expected a string but received null. This prevents get_sentry_resource from returning issue and breadcrumbs resources for affected events.

API contract evidence

This is a valid server response, not a server bug. The Sentry event serializer declares dateReceived as datetime | None; when received is absent or invalid, the serializer can return null:

• getsentry/sentry event serializer, lines 155-176
• getsentry/sentry event serializer, lines 328-368

Related precedent

• fix(api-client): allow null firstSeen/lastSeen on IssueSchema #910 made nullable firstSeen and lastSeen API dates accept null with z.string().datetime().nullable().
• fix(api-client): update event schema to match Sentry API responses #520 fixed occurrence: null for transaction events after an EventSchema Zod error.
• fix(events): include user geo in formatted output #894 aligned event user and geo fields that can be null.
• fix(mcp-core): Allow null for externalSlug/externalId in RepositorySchema #1236 proposes nullish() for API fields where optional() rejects explicit null.

Change

• Change dateReceived to z.string().datetime().nullish(). This follows the nullable-date intent of fix(api-client): allow null firstSeen/lastSeen on IssueSchema #910 while also retaining support for omitted fields.
• Change generic occurrence to OccurrenceSchema.nullish(), consistent with the nullish() approach proposed in fix(mcp-core): Allow null for externalSlug/externalId in RepositorySchema #1236 and the transaction-event handling in fix(api-client): update event schema to match Sentry API responses #520.
• Add a focused EventSchema regression test for dateReceived: null and generic occurrence: null.

Testing and regression coverage

The focused Vitest regression test was added but could not be run locally: Corepack was unable to download the repository-pinned pnpm@11.8.0 after 120-second and 300-second attempts, so dependencies could not be installed. git diff --check passes.

CI should run the new test with:

pnpm --filter @sentry/mcp-core exec vitest run src/api-client/schema.test.ts

[sentry-junior]

The schema changes match upstream Sentry: BaseEventSerializerResponse declares both dateReceived and occurrence nullable, and EventSerializer.serialize() emits None for each when absent. The focused Vitest test passes, but the new assertion result.occurrence makes the repository's required pnpm run tsc fail with TS2339 because EventSchema.parse() returns a union that includes variants without that property. Please rewrite the assertion so it narrows/checks the property first (or otherwise remains valid against the union), then confirm the root typecheck passes.

[dcramer]

will have junior clean up the remainder, thanks!

Addressed in commit 73a76be; root typecheck now passes.

[sentry-junior]

Addressed the review feedback in 73a76be: the null occurrence assertion now preserves EventSchema union typing. Verified locally with pnpm run tsc, pnpm run lint, pnpm run test, and the focused 44-test schema suite. The full lint gate passes with one unrelated pre-existing unused-import warning in packages/mcp-cloudflare/src/server/oauth/helpers.test.ts.