Early self-reference allows deletion with conflicts

[smailliwcs]

Describe the bug

A resource that is referenced both from itself and from other resources can be deleted despite conflicts. This issue is sensitive to the order in which the references are made: the self-reference must be created before any "external" references. I.e., the first relevant record in HFJ_RES_LINK must be the self-reference, which causes DeleteConflictService to ignore it.

To Reproduce

#!/bin/bash

unlinked='{
  "resourceType": "Patient",
  "id": "$id",
  "name": [
    {
      "family": "Doe"
    }
  ]
}'
linked='{
  "resourceType": "Patient",
  "id": "$id",
  "name": [
    {
      "family": "Doe"
    }
  ],
  "link": [
    {
      "other": {
        "reference": "Patient/$other_id"
      },
      "type": "seealso"
    }
  ]
}'

put() {
    local template="$1"; shift
    local id="$1"; shift
    local other_id="$1"; shift
    export id
    export other_id
    echo "PUT $id"
    echo "$template" \
    | envsubst \
    | curl -sSX PUT "http://localhost:8080/fhir/Patient/$id" \
        -H 'Content-Type: application/fhir+json' \
        --data-binary @- \
        -o /dev/null
}

delete() {
    local id="$1"; shift
    echo "DELETE $id"
    curl -sSX DELETE "http://localhost:8080/fhir/Patient/$id" \
    | jq -r '.issue[].diagnostics'
}

docker run --name hapi -p 8080:8080 -d hapiproject/hapi:latest
while ! curl -sX GET 'http://localhost:8080/' -o /dev/null; do
    echo -n '.'
    sleep 1
done
echo

echo

echo 'No self-reference'
put "$unlinked" 'target-1'
put "$linked" 'source-1' 'target-1'
delete 'target-1'

echo

echo 'Self-reference after source'
put "$unlinked" 'target-2'
put "$linked" 'source-2' 'target-2'
put "$linked" 'target-2' 'target-2'
delete 'target-2'

echo

echo 'Self-reference before source'
put "$unlinked" 'target-3'
put "$linked" 'target-3' 'target-3'
put "$linked" 'source-3' 'target-3'
delete 'target-3'

echo

docker rm -f hapi

Typical output:

0c4b78adb59a84e6ff30b65cf893f1057f0644da6f33fe4a80fdb5a6c68de78c
.....................

No self-reference
PUT target-1
PUT source-1
DELETE target-1
Unable to delete Patient/target-1 because at least one resource has a reference to this resource. First reference found was resource Patient/source-1 in path Patient.link.other

Self-reference after source
PUT target-2
PUT source-2
PUT target-2
DELETE target-2
Unable to delete Patient/target-2 because at least one resource has a reference to this resource. First reference found was resource Patient/source-2 in path Patient.link.other

Self-reference before source
PUT target-3
PUT target-3
PUT source-3
DELETE target-3
Successfully deleted 1 resource(s). Took 12ms.

hapi

Expected behavior

Admittedly, this might be a "bad data" situation. But given that HAPI allows you to create self-references, it should handle them appropriately during deletion. I.e., DeleteConflictService should detect "external" references even in the presence of early self-references. Perhaps by filtering out self-references in DeleteConflictFinderService?

Environment

• hapiproject/hapi:v8.0.0-1