Bad JSON export when predicate is deleted

[miko]

What version of Dgraph are you using?

1.2.1

Have you tried reproducing the issue with the latest release?

No

What is the hardware spec (RAM, OS)?

Not relevant

Steps to reproduce the issue (command/config used to run Dgraph).

Create 1.schema:

type Floor {
	name
  open
	<~building.floors>
}
type Building {
	name
	building.floors
}
<name>:string @index(exact) . 
<building.floors>:[uid] @reverse . 
<open>:bool .

Create data.rdf:

<0x1> <name> "Building1"^^<xs:string> .
<0x1> <dgraph.type> "Building"^^<xs:string> .
<0x1> <building.floors> <0x2> .
<0x1> <building.floors> <0x3> .
<0x2> <name> "1"^^<xs:string> .
<0x2> <open> "false"^^<xs:boolean> .
<0x2> <dgraph.type> "Floor"^^<xs:string> .
<0x2> <building.floors> <0x1> .
<0x3> <name> "2"^^<xs:string> .
<0x3> <open> "true"^^<xs:boolean> .
<0x3> <dgraph.type> "Floor"^^<xs:string> .
<0x3> <building.floors> <0x1> .

Remove one predicate:
curl -H "Content-Type: application/json" -X POST localhost:8080/mutate?commitNow=true -d $'{"delete":[{"uid":"0x3","open":null}]}'

Export as JSON:
curl http://localhost:8080/admin/export

Expected behaviour and actual result.

Actual result:

zcat export/dgraph.r*/g01.json.gz
[
  {"uid":"0x1","name":"Building1"},
  {"uid":"0x2","name":"1"},
  {"uid":"0x3","name":"2"},
  {"uid":"0x2","open":"false"},
,
  {"uid":"0x1","dgraph.type":"Building"},
  {"uid":"0x2","dgraph.type":"Floor"},
  {"uid":"0x3","dgraph.type":"Floor"},
  {"uid":"0x1","building.floors":[{"uid":"0x2"}]},
  {"uid":"0x1","building.floors":[{"uid":"0x3"}]},
  {"uid":"0x2","building.floors":[{"uid":"0x1"}]},
  {"uid":"0x3","building.floors":[{"uid":"0x1"}]}
]

Expected:

[
  {"uid":"0x1","name":"Building1"},
  {"uid":"0x2","name":"1"},
  {"uid":"0x3","name":"2"},
  {"uid":"0x2","open":"false"},
  {"uid":"0x1","dgraph.type":"Building"},
  {"uid":"0x2","dgraph.type":"Floor"},
  {"uid":"0x3","dgraph.type":"Floor"},
  {"uid":"0x1","building.floors":[{"uid":"0x2"}]},
  {"uid":"0x1","building.floors":[{"uid":"0x3"}]},
  {"uid":"0x2","building.floors":[{"uid":"0x1"}]},
  {"uid":"0x3","building.floors":[{"uid":"0x1"}]}
]

(with no empty line containing only a comma)

Currently exporting in JSON format generates invalid JSON files (when a predicate was deleted)

[MichelDiz]

Hi Miko,

Thanks for your ticket, this is a known issue and it is already fixed by #4773

duplicated of #3610

Cheers.

[miko]

Shouldn't it backported to 1.2.x version? In case someone wants to upgrade to 2.0.0?