[COUCHDB-2978] Stale ETags are re-used for _local docs

• Type: Bug
• Status: Resolved
• Priority: Blocker
• Resolution: Fixed
• Fix Version/s: 2.0.0, 1.7.0
• Component/s: HTTP Interface
• Assignee: Garren Smith
• Reporter: Nolan Lawson
• Created: 31/Mar/16 13:57
• Updated: 12/Apr/16 08:59
• Resolved: 12/Apr/16 08:59

Description

CouchDB re-uses the same ETags for _local documents even when the content of the _local document has changed, meaning that clients who cache based on the ETag may end up with permanently stale content. To reproduce the bug, it's simply:

1. Create a _local doc
2. Fetch the doc, ETag is "0-1"
3. Delete the database (or the _local doc)
4. Recreate the database (or the _local doc), insert a changed _local doc
5. Fetch the doc, ETag is still "0-1" and therefore the client may end up with a stale version.

Here are related issues in PouchDB and WebKit for further details:

• PouchDB bug
• WebKit bug