[COUCHDB-3131] Valid JSON rejected in _changed query with filter

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Won't Fix
• Affects Version/s: 2.0.0
• Component/s: HTTP Interface
• Assignee: Unassigned
• Reporter: Samuel Tardieu
• Created: 06/Sep/16 12:18
• Updated: 02/Sep/18 07:07
• Resolved: 02/Sep/18 07:07

Description

While testing 2.0.0-RC4, I noticed some oddities when giving a valid JSON payload to a POST _changes request involving a filter: only one document seem to go through the filter (and may or may not match) then nothing more is sent.

In short, everything works if you send a request with "Content-Type: application/json", "Content-Length: 0", and an empty payload. However, this is not valid JSON, as explained in issue COUCH-2583 for another command.

As an example, I have a "test" database with a "d/f" filter which contains a function testing that doc.name is equal to "foo".

Here is a query with an invalid JSON payload:

%  curl -H "Content-Type: application/json" --data "" -v "http://localhost:5984/test/_changes?filter=d/f&feed=continuous&heartbeat=30000"
                                        
*   Trying ::1...
* Connected to localhost (::1) port 5984 (#0)
> POST /test/_changes?filter=d/f&feed=continuous&heartbeat=30000 HTTP/1.1
> Host: localhost:5984
> User-Agent: curl/7.50.1
> Accept: */*
> Content-Type: application/json
> Content-Length: 0
> 
< HTTP/1.1 200 OK
< Cache-Control: must-revalidate
< Content-Type: application/json
< Date: Tue, 06 Sep 2016 12:16:32 GMT
< Server: CouchDB/1df597f (Erlang OTP/17)
< Transfer-Encoding: chunked
< X-Couch-Request-ID: 422e7cd090
< X-CouchDB-Body-Time: 0
< 
{"seq":"2-g1AAAAFReJzLYWBg4MhgTmHgzcvPy09JdcjLz8gvLskBCjMlMiTJ____PyuRAYeCJAUgmWSPX40DSE08SE0GcyJTLpDHbpSamGpsaIyuHpcJCSAT6vHakscCJBkagBRQ2XxC6hZA1O0npO4ARN19QuoeQNSB3JcFALv_a5o","id":"t1","changes":[{"rev":"2-0d4850a48036a083e9f18f94f6cb9abe"}]}
{"seq":"4-g1AAAAGneJzLYWBg4MhgTmHgzcvPy09JdcjLz8gvLskBCjMlMiTJ____PyuDOZExFyjAnmKZlmhibIauGIf2JAUgmWQPNYEBbIJ5okGimbFhCgNnaV5KalpmXmoKLt0OIN3xUN1MYN1GqYmpxobGxNqfADKhHmRCIgMONXksQJKhAUgBlc0npG4BRN1-RIgkJqaYWSSnEukiiCkHIKbcJ2TbA4g6kOuzAM6WhBY","id":"t3","changes":[{"rev":"1-bc98e8ae0f9c89fbc8c237dfc9bfe478"}]}
{"seq":"11-g1AAAAIbeJyV0UsOgjAQBuAKGnXhGfQIhZq2rOQmOqVtkGC7UNd6E72J3kRvguWRQExIYDOTTPp_k3RyhNAi9SVaGWusVLGxqT1fcjf2AIl1URRZ6sPk5AZzGWnYEvr_uCcuNq6KXSOgSmCAgZJAouXVSKWPRsm-dFym903aq9KhAkUCMnT_oRRujTCrBK1JBFgPFMzUVXR3zSGP9h8wJzTkbJTyrJVXqwBIyhM1SnnXyqdVSCICqvgo5VsrnbtgHLCEie5dsh9GyaSG","id":"9a1c0e93e4aa88c45c3e38031d5cc7f3","changes":[{"rev":"1-bc98e8ae0f9c89fbc8c237dfc9bfe478"}]}
{"seq":"12-g1AAAAIbeJyV0UsOgjAQBuAKGnXhGfQIhZq2rOQmOqVtkGC7UNd6E72J3kRvguWRQExIYDNNJvN_TWZyhNAi9SVaGWusVLGxqT1fctf2AIl1URRZ6sPk5BpzGWnYEvo_3BMXG1fFrhFQJTDAQEkg0fJqpNJHo2RfOi7T-ybtVelQgSIBGfr_oRRujTCrBK1JBFgPFMzUVXR3j0Me7R4wJzTkbJTyrJVXqwBIyhM1SnnXyqfdCUlEQBUfpXxrpXMXjAOWMNG9S_YDRymkhw","id":"9a1c0e93e4aa88c45c3e38031d5e6c11","changes":[{"rev":"1-bc98e8ae0f9c89fbc8c237dfc9bfe478"}]}
{"seq":"13-g1AAAAIbeJyV0UsOgjAQBuAKGnXhGfQILTWlrOQmOqVtkGC7UNd6E72J3kRvguWRQExIYDOTTPp_k3RyhNAi9SVaGWusVLGxqT1fcjf2AIl1URRZ6sPk5AZzGWnYUvb_uCcuNq6KXSOgSggBA6NEouXVSKWPRsm-dFym903aq9KBAkUJHbr_UAq3RphVgtY0AqwHCmbqKrq75pBH-w-YUxbwcJTyrJVXqwBIxhM1SnnXyqdU_EqhiSBM8VHKt1Y6d8GYhEkounfJfkeJpIg","id":"t2","changes":[{"rev":"1-bc98e8ae0f9c89fbc8c237dfc9bfe478"}]}

(everything has been returned, it works, but I had to send an invalid empty payload which is not valid JSON)

However, if I try to send "{}" which is a valid JSON payload:

 % curl -H "Content-Type: application/json" --data "{}" -v "http://localhost:5984/test/_changes?filter=d/f&feed=continuous&heartbeat=30000"
            
*   Trying ::1...
* Connected to localhost (::1) port 5984 (#0)
> POST /test/_changes?filter=d/f&feed=continuous&heartbeat=30000 HTTP/1.1
> Host: localhost:5984
> User-Agent: curl/7.50.1
> Accept: */*
> Content-Type: application/json
> Content-Length: 2
> 
* upload completely sent off: 2 out of 2 bytes

Nothing at all is sent back.

This is a regression as this request works against CouchDB 1.x.