[COUCHDB-3239] incorrect ordering of results when using open_revs and latest=true

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Won't Fix
• Affects Version/s: 2.0.0
• Component/s: Database Core
• Assignee: Unassigned
• Reporter: Will Holley
• Created: 18/Nov/16 13:06
• Updated: 02/Sep/18 07:06
• Resolved: 02/Sep/18 07:06

Description

When fetching open_revs with latest=true for a conflicted document, the order of results is incorrect. For example, if I create a document with the rev tree:

			4-d1
			/
		3-c1
		/
	2-b1
	/
1-a 
	\
	2-b2
		\
		3-c2

and ask for open_revs=["2-b1","2-b2"]&latest=true, the response will return 3-c2 followed by 4-d1 - the reverse of what I'd expect.

Below is a test/reproduction executed against Couch 1.6.1 and 2.0.

1.6.1:

$ export COUCH_HOST="http://127.0.0.1:5984"

$ curl -XPUT "$COUCH_HOST/open_revs_test"
{"ok":true}

$ curl "$COUCH_HOST/open_revs_test/_bulk_docs" -H "Content-Type:application/json" -XPOST -d @docs.json
[]

# GET open_revs=["2-b1","2-b2"]
$ curl -H "Accept:application/json" "$COUCH_HOST/open_revs_test/mydoc?open_revs=%5B%222-b1%22%2C%222-b2%22%5D"
[{"ok":{"_id":"mydoc","_rev":"2-b1","value":"x-winning"}},{"ok":{"_id":"mydoc","_rev":"2-b2","value":"x-losing"}}]

# GET open_revs=["2-b1","2-b2"]&latest=true
$ curl -H "Accept:application/json" "$COUCH_HOST/open_revs_test/mydoc?open_revs=%5B%222-b1%22%2C%222-b2%22%5D&latest=true"
[{"ok":{"_id":"mydoc","_rev":"4-d1","value":"z-winning"}},{"ok":{"_id":"mydoc","_rev":"3-c2","value":"y-losing"}}]

2.0:

$ export COUCH_HOST="http://127.0.0.1:15984"

$ curl -XPUT "$COUCH_HOST/open_revs_test"
{"ok":true}

$ curl "$COUCH_HOST/open_revs_test/_bulk_docs" -H "Content-Type:application/json" -XPOST -d @docs.json
[]

# GET open_revs=["2-b1","2-b2"]
$ curl -H "Accept:application/json" "$COUCH_HOST/open_revs_test/mydoc?open_revs=%5B%222-b1%22%2C%222-b2%22%5D"
[{"ok":{"_id":"mydoc","_rev":"2-b1","value":"x-winning"}},{"ok":{"_id":"mydoc","_rev":"2-b2","value":"x-losing"}}]

# GET open_revs=["2-b1","2-b2"]&latest=true
$ curl -H "Accept:application/json" "$COUCH_HOST/open_revs_test/mydoc?open_revs=%5B%222-b1%22%2C%222-b2%22%5D&latest=true"
[{"ok":{"_id":"mydoc","_rev":"3-c2","value":"y-losing"}},{"ok":{"_id":"mydoc","_rev":"4-d1","value":"z-winning"}}]

Note the reversed order of the results in 2.0 when latest=true is specified.