SUPPORT SUPERDAY: Lolu

[jesuloluwao]

Problem

The Customer.io PostHog plugin currently only sends events when the current event payload contains an email. If a user provides their email in one event but omits it in subsequent events, those later events are dropped or attributed to a separate profile by distinct_id, causing fragmented customer data in Customer.io.

Changes

• Persist each user’s last known valid email in plugin storage under customer-email/<distinct_id>.
• In syncCustomerMetadata, capture and validate emails from $set.email and store them; if an event lacks an email, retrieve the stored email.
• In exportSingleEvent, only skip sending if no email is ever known. Otherwise, use the stored (or current) email as the Customer.io identifier.
• Updated shouldCustomerBeTracked to rely on the actual presence of an email rather than just a status flag.
• Added basic email format validation to prevent storing malformed addresses.

Did you write or update any docs for this change?

• I've added or updated the docs
• I've reached out for help from the docs team
• No docs needed for this change

How did you test this code?

• Automated tests simulate three scenarios for distinct_id = "user123":
  1. Initial event with email ($set.email = "user@acme.com"): plugin stores email and sends identify/track calls using "user@acme.com".
  2. Subsequent event without email: plugin retrieves stored "user@acme.com" and successfully tracks the event under the same profile.
  3. Email update event ($set.email = "new@acme.com"): plugin validates, updates storage, and all following events use "new@acme.com".
• Manual testing in a PostHog instance confirmed that once an email is captured, all future events (even those without $set.email) appear under one Customer.io profile.
• Verified no regression in scenarios where users never provide an email (events continue to be skipped).

[jesuloluwao]

@abigailbramble Please review