Fixes for _local doc update and _bulk_docs operations with new_edits false

[eiri]

Overview

This PR is mostly a refactoring and addresses the following issues:

• Attempt to create a local document with an invalid revision throwing badarg exception.
• The documents with _local prefix written into a wrong btree on a bulk operation with new_edits set to false.
• It is possible to create a document with an empty id on a bulk operation with new_edits set to false

Testing recommendations

New tests are expected to pass.

For manual testing here is an expected change of behaviour:

Readable error on an invalid rev for a local doc creation

curl -X PUT http://127.0.0.1:15984/koi/_local/alice?rev=0-abcdf -d '{"name":"Alice"}'
{"error":"error","reason":"Invalid rev format"}

Correct creation of a local doc on a bulk update

$ curl -X POST http://127.0.0.1:15984/koi/_bulk_docs -d '{"new_edits":false, "docs": [{"_id":"_local/alice", "_rev":"0-1", "name":"Alice"}]}'
[]
$ curl http://127.0.0.1:15984/koi/_local/alice
{"_id":"_local/alice","_rev":"0-2","name":"Alice"}

Generation of a missing id on a bulk update

$ curl -X POST http://127.0.0.1:15984/koi/_bulk_docs -d '{"new_edits":false, "docs": [{"_rev":"1-abcdefgh", "name":"Alice"}]}'
[]
$ curl http://127.0.0.1:15984/koi/_all_docs -G -d include_docs=true
{"total_rows":1,"offset":0,"rows":[
{"id":"ce4c2d25c9d580c1c5e06a05bb000443","key":"ce4c2d25c9d580c1c5e06a05bb000443","value":{"rev":"1-abcdefgh"},"doc":{"_id":"ce4c2d25c9d580c1c5e06a05bb000443","_rev":"1-abcdefgh","name":"Alice"}}
]}

Related Issues or Pull Requests

This closes #1628

Checklist

• Code is written and works correctly;
• Changes are covered by tests;
• Documentation reflects the changes;

[iilyak]

WARNING: Most likely very subjective proposal. How about creating a function increment_revision(#doc{}) -> #doc{} | undefined and put try/catch there. Then we can rewrite foldl as follows:

lists:foldl(fun({Client, NewDoc}, Acc) ->
   case increment_revision(NewDoc) of
      #doc{revs = {0, [NewRev | _]}} = Doc ->
          send_result(Client, Doc, {ok, {0, integer_to_binary(NewRev)}}),
          [Doc | Acc];
      _ -> 
          send_result(Client, NewDoc, {error, <<"Invalid rev format">>}),
          Acc
   end
end, [], Docs).

[iilyak]

💯

[iilyak]

interesting approach

[iilyak]

+1. Nice work

New tests pass.

Had to update commands for manual tests to include ContentType and auth. Everything works as advertised.

[eiri]

@iilyak I've extracted increment_local_doc_revs into a separate function as you suggested. Can you take a look, please, if this is what you had in mind?

[iilyak]

Perfect. Thank you @eiri.