fix(email): set Message-ID header on every outbound message #428

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Claude-Run merged 1 commit from fix/PMS-624-outbound-message-id into main

2026-07-04 04:15:27 +02:00

Claude-Run commented

2026-07-04 04:05:48 +02:00

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lettre's MessageBuilder::build auto-inserts Date when missing but never generates a Message-ID unless one is set explicitly. All three SMTP send paths (send_password_reset, send_welcome, send_text) built messages without calling .message_id(...), so outbound mail shipped with no Message-ID header. Google Workspace rejects such messages, bouncing them for at least one recipient.

Route every send through a shared base_builder that sets From, To, and a fresh <uuid@from-domain> Message-ID. The domain is taken from the configured From address (lettre's hostname feature is disabled, so the built-in message_id(None) path would produce @localhost); anchoring to the sending domain keeps the id RFC 5322 valid and deliverable. Date continues to be added automatically by lettre.

Add unit tests asserting the generated Message-ID is unique and anchored to the From domain, and that a message built via base_builder carries both Message-ID and Date headers, so the invariant is enforced mechanically.

#PMS-624

lettre's `MessageBuilder::build` auto-inserts `Date` when missing but never generates a `Message-ID` unless one is set explicitly. All three SMTP send paths (`send_password_reset`, `send_welcome`, `send_text`) built messages without calling `.message_id(...)`, so outbound mail shipped with no `Message-ID` header. Google Workspace rejects such messages, bouncing them for at least one recipient. Route every send through a shared `base_builder` that sets `From`, `To`, and a fresh `<uuid@from-domain>` `Message-ID`. The domain is taken from the configured From address (lettre's `hostname` feature is disabled, so the built-in `message_id(None)` path would produce `@localhost`); anchoring to the sending domain keeps the id RFC 5322 valid and deliverable. `Date` continues to be added automatically by lettre. Add unit tests asserting the generated Message-ID is unique and anchored to the From domain, and that a message built via `base_builder` carries both `Message-ID` and `Date` headers, so the invariant is enforced mechanically. #PMS-624

Claude-Run added 1 commit

2026-07-04 04:05:48 +02:00

fix(email): set Message-ID header on every outbound message

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10bfc58e29

lettre's `MessageBuilder::build` auto-inserts `Date` when missing but never generates a `Message-ID` unless one is set explicitly. All three SMTP send paths (`send_password_reset`, `send_welcome`, `send_text`) built messages without calling `.message_id(...)`, so outbound mail shipped with no `Message-ID` header. Google Workspace rejects such messages, bouncing them for at least one recipient.

Route every send through a shared `base_builder` that sets `From`, `To`, and a fresh `<uuid@from-domain>` `Message-ID`. The domain is taken from the configured From address (lettre's `hostname` feature is disabled, so the built-in `message_id(None)` path would produce `@localhost`); anchoring to the sending domain keeps the id RFC 5322 valid and deliverable. `Date` continues to be added automatically by lettre.

Add unit tests asserting the generated Message-ID is unique and anchored to the From domain, and that a message built via `base_builder` carries both `Message-ID` and `Date` headers, so the invariant is enforced mechanically.

#PMS-624