Expired document regression with expiresAt check

[johnnyoshika]

Problem

In version 2.0, we introduced a client-side expiresAt check in IDatabase's Get to ensure that expired documents don't get returned:

ltijs-firestore/src/Firestore.ts

Line 90 in d84b5d6

.filter(doc => !this.hasExpired(doc));

This client-side check is required because Firestore's TTL's deletion time in non-deterministic. Excerpt: https://firebase.google.com/docs/firestore/ttl#ttl_deletion

Deletion through TTL is not an instantaneous process. Expired documents continue to appear in queries and lookup requests until the TTL process actually deletes them. TTL trades deletion timeliness for the benefit of reduced total cost of ownership for deletions. Data is typically deleted within 72 hours after its expiration date.

A regression was introduced because we don't reset expiresAt when document is replaced:

ltijs-firestore/src/Firestore.ts

Line 217 in d84b5d6

else transaction.update(snap.docs[0].ref, newDocData);

This means that a fresh document can be updated for an existing but expired document. Such document will not be returned by Get. So in other words:

• If a document expired but is still in Firestore
• That document is replaced by LTIJS by calling IDatabase.Replace()
• Inside IDatabase.Replace(), that document is updated but expiresAt doesn't get extended
• That document can never be retrieved by IDatabase.Get() because it will still be tagged with the old expiresAt date

Requirement

Reset timestamps (including expiresAt) in Replace:

ltijs-firestore/src/Firestore.ts

Line 217 in d84b5d6

else transaction.update(snap.docs[0].ref, newDocData);