1137102 - Duplicate items in specific RSS feed (Thunderbird)

Status: RESOLVED INVALID

(Thunderbird :: Untriaged, defect)

Description

[Andys]

Attachment: rss_duplicate_items.zip

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:25.1) Gecko/20141110 Firefox/31.9 PaleMoon/25.1.0
Build ID: 20141110140305

Steps to reproduce:

1. subscribe to feed https://vivaldi.net/blogs/teamblog?format=feed&type=rss
2. feed items are downloaded, nothing wrong
3. leave thunderbird running for 1-2 days (update interval is 100 minutes)



Actual results:

Occasionally, after a long interval (1-3 days) there will be new unread duplicates for all old items in feed (currently on 02/26 have 2 duplicate items dated 02/25, and got 3 duplicates for all older items). Dates for duplicate items are the same as original, I exported and attached source files of duplicates (doubt it will help since it's in html format and raw rss entries aren't stored).
Please note:
- Manually updating this feed does _not_ produce duplicates, they appear sporadically every other day.
- I have 5 other RSS feeds, they don't have this problem.

In few hours, I will set up a VM to check if the problem would reproduce on clean system with clean TB profile, maybe it's leftovers from upgrade process

Comment 1

[Andys]

Well, it happened somewhere during today's night. There are two of each items in my test thunderbird environment

Comment 2

[alta88]

The reason is publisher reuse of unique ids, as described in the FAQ here:
https://support.mozilla.org/en-US/kb/how-subscribe-news-feeds-and-blogs