Cannot load dependent modules via REST API

[tsandall]

The REST API doesn't allow callers to load dependent modules one-by-one:

test1.rego:

package ex

import request.req1

x :- req1 > 1

test2.rego:

package ex

y :- x with request.req1 as 1000

Example:

torin:~$ curl -X PUT localhost:8181/v1/policies/test1 --data-binary @test1.rego
{
  "ID": "test1",
  "Module": {
    "Package": {
      "Path": [
        {
          "Type": "var",
          "Value": "data"
        },
        {
          "Type": "string",
          "Value": "ex"
        }
      ]
    },
    "Imports": null,
    "Rules": [
      {
        "Name": "x",
        "Value": {
          "Type": "boolean",
          "Value": true
        },
        "Body": [
          {
            "Index": 0,
            "Terms": [
              {
                "Type": "var",
                "Value": "gt"
              },
              {
                "Type": "ref",
                "Value": [
                  {
                    "Type": "var",
                    "Value": "request"
                  },
                  {
                    "Type": "string",
                    "Value": "req1"
                  }
                ]
              },
              {
                "Type": "number",
                "Value": 1
              }
            ]
          }
        ]
      }
    ]
  }
}torin:~$ curl -X PUT localhost:8181/v1/policies/test1 --data-binary @test2.rego
{
  "Code": 400,
  "Message": "error(s) occurred while compiling module(s), see Errors",
  "Errors": [
    {
      "Code": 2,
      "Location": {
        "File": "test1",
        "Row": 3,
        "Col": 1
      },
      "Message": "y: x is unsafe (variable x must appear in the output position of at least one non-negated expression)"
    }
  ]
}

However, if we run OPA and pass the modules via the command line, everything works fine:

Run OPA:

./opa_darwin_amd64 run -s --v=3 --logtostderr=1 ~/test1.rego ~/test2.rego

List policies:

torin:~$ curl localhost:8181/v1/policies --silent | jq '.[].ID'
"/Users/torin/test1.rego"
"/Users/torin/test2.rego"

Query for data:

torin:~$ curl localhost:8181/v1/data
{"ex":{"y":true}}

[tsandall]

Oops. The second PUT was overwriting the first--as a result this behaviour was expected.