fix(firestore-send-email): kit/extension parity – kit cannot deploy for databases in northamerica-south1 or europe-north2 #3296

firestore-send-email kit/extension parity. Priority: medium. The kit can't be deployed for databases in northamerica-south1 or europe-north2.

Difference

• Extension: the function runs in the extension's location (us-central1 by default). Only the Eventarc trigger uses DATABASE_REGION, so both regions in its option list work.
• Kit: the function itself is placed in DATABASE_REGION. Only the multi-regions are remapped; regional values are used as-is. Cloud Functions (2nd gen) isn't available in northamerica-south1 or europe-north2, so the deploy fails. Both regions are still offered in the kit's DATABASE_REGION list, and there is no workaround: a blank value puts the function in us-central1, but no longer next to the database.

Reproduced

• The Cloud Functions v2 locations list for the test project (40 entries) includes neither region.
• A kit instance deployed with DATABASE_REGION=europe-north2 fails: generateUploadUrl had HTTP Error: 403, Location europe-north2 is not found or access is unauthorized.

Code

• Extension: extension.yaml#L63 (trigger region only), options at #L121-L122 and #L153-L154
• Kit: region.ts#L19-L40, config.ts#L383-L395, README #L171-L180

Resolution

Map these two locations to the nearest region that offers Cloud Functions, as is already done for nam5/eur3. The Firestore trigger still fires in the database's own region. Also correct the README's "used as-is" wording.