Passing "stub": false without passing the attachment causes an unknown_error

[SCdF]

If you're uploading a document with attachments and you say it's not a stub without then also passing the attachment, you get an unfriendly error and an exception thrown in the log.

Expected Behavior

There should be a clean and readable error similar to when "stub": true and the attachment missing.

Current Behavior

You get {"error":"unknown_error","reason":"function_clause","ref":93628465} returned and the log shows:

[error] 2017-08-31T14:17:53.315121Z couchdb@localhost <0.23961.0> 6cdd28e8a6 req_err(93628465) unknown_error : function_clause
    [<<"base64:decode/1 L114">>,<<"couch_att:inline_from_json/2 L411">>,<<"couch_doc:-transfer_fields/2-lc$^0/1-2-/1 L235">>,<<"couch_doc:transfer_fields/2 L235">>,<<"couch_doc:from_json_obj_validate/1 L129">>,<<"chttpd_db:db_req/2 L328">>,<<"chttpd:process_request/1 L295">>,<<"chttpd:handle_request_int/1 L231">>]
[notice] 2017-08-31T14:17:53.315363Z couchdb@localhost <0.23961.0> 6cdd28e8a6 localhost:5984 127.0.0.1 undefined POST /attachment-test 500 ok 1

Steps to Reproduce (for bugs)

To follow along:

scdf at SCdF in ~
$ curl -X PUT http:https://admin:pass@localhost:5984/attachment-test
{"ok":true}
scdf at SCdF in ~
$ curl -X POST -H 'Content-Type: application/json' http:https://admin:pass@localhost:5984/attachment-test -d '{    "_id": "attachment-test",    "_attachments": {        "static/manifest.json": {            "content
_type": "application/json",            "digest": "md5-aFoQ0Neouur23mVxaLYoNA==",            "length": 30
3,            "revpos": 88,            "stub": true        }    }}'
{"error":"missing_stub","reason":"Invalid attachment stub in attachment-test for static/manifest.json"}
scdf at SCdF in ~
$ curl -X POST -H 'Content-Type: application/json' http:https://admin:pass@localhost:5984/attachment-test -d '{    "_id": "attachment-test",    "_attachments": {        "static/manifest.json": {            "content_type": "application/json",            "digest": "md5-aFoQ0Neouur23mVxaLYoNA==",            "length": 303,            "revpos": 88,            "stub": false        }    }}'
{"error":"unknown_error","reason":"function_clause","ref":93628465}

Note:

• In the first POST I pass "stub": true and I get a nice error about not passing the attachment
• In the second POST I changed stub from true to false, and we get the unfriendly "unknown_error" error message.

Your Environment

• Version used: CouchDB 2.1.0
• Operating System and version (desktop or mobile): MacOS 10.12.6