Support decision table inputs and outputs without names/labels

[korthout]

Description

A decision tables' inputs and outputs must have an id and can have a name. What we define as a name differs between inputs and outputs. For inputs, we used only the label from the XML which is not mandatory. For outputs, we used only the name, but it is only mandatory when multiple outputs exist.

Even though the internal decision engine was already able to deal with this, the workflow engine wasn't. It would try to write the EvaluationEvent record with an EvaluatedInputRecord (or EvaluatedOutputRecord) and then fail writing it because of a NullPointerException.

After discussing with the Operate team (who uses this name value), we came to the conclusion that we want the same behavior as the Modeler:

• Inputs can have a label in the XML, when defined we use it as the name. Otherwise, we use the input's expression as name.
• Outputs can have a label in the XML, when defined we use it as the name. Otherwise, we use the output's name.

This PR adjusts which values are used as the names for inputs and outputs of evaluated decision tables. It also makes sure these records can be written when the name of the input or output is undefined.

Related issues

closes #8909

Definition of Done

Not all items need to be done depending on the issue and the pull request.

Code changes:

• The changes are backwards compatibility with previous versions
• If it fixes a bug then PRs are created to backport the fix to the last two minor versions. You can trigger a backport by assigning labels (e.g. backport stable/1.3) to the PR, in case that fails you need to create backports manually.

Testing:

• There are unit/integration tests that verify all acceptance criterias of the issue
• New tests are written to ensure backwards compatibility with further versions
• The behavior is tested manually
• The change has been verified by a QA run
• The impact of the changes is verified by a benchmark

Documentation:

• The documentation is updated (e.g. BPMN reference, configuration, examples, get-started guides, etc.)
• New content is added to the release announcement
• If the PR changes how BPMN processes are validated (e.g. support new BPMN element) then the Camunda modeling team should be informed to adjust the BPMN linting.

[korthout]

Manually tested to see if it could be successfully exported to ES:

{
  "_index": "zeebe-record_decision-evaluation_1.4.0-snapshot_2022-03-16",
  "_type": "_doc",
  "_id": "1-50",
  "_version": 1,
  "_score": 1,
  "_routing": "1",
  "_source": {
    "partitionId": 1,
    "value": {
      "decisionVersion": 5,
      "decisionOutput": "\"Obi-Wan Kenobi\"",
      "evaluatedDecisions": [
        {
          "decisionType": "DECISION_TABLE",
          "evaluatedInputs": [
            {
              "inputId": "Input_1",
              "inputName": "",
              "inputValue": "\"blue\""
            }
          ],
          "decisionVersion": 4,
          "decisionOutput": "\"Jedi\"",
          "matchedRules": [
            {
              "ruleId": "DecisionRule_0zumznl",
              "ruleIndex": 1,
              "evaluatedOutputs": [
                {
                  "outputId": "Output_1",
                  "outputName": "",
                  "outputValue": "\"Jedi\""
                }
              ]
            }
          ],
          "decisionId": "jedi_or_sith",
          "decisionName": "Jedi or Sith",
          "decisionKey": 2251799813685265
        },
        {
          "decisionType": "DECISION_TABLE",
          "evaluatedInputs": [
            {
              "inputId": "InputClause_0qnqj25",
              "inputName": "",
              "inputValue": "\"Jedi\""
            },
            {
              "inputId": "InputClause_0k64hys",
              "inputName": "",
              "inputValue": "185"
            }
          ],
          "decisionVersion": 5,
          "decisionOutput": "\"Obi-Wan Kenobi\"",
          "matchedRules": [
            {
              "ruleId": "DecisionRule_0uin2hk",
              "ruleIndex": 2,
              "evaluatedOutputs": [
                {
                  "outputId": "OutputClause_0hhe1yo",
                  "outputName": "",
                  "outputValue": "\"Obi-Wan Kenobi\""
                }
              ]
            }
          ],
          "decisionId": "force_user",
          "decisionName": "Which force user?",
          "decisionKey": 2251799813685266
        }
      ],
      "evaluationFailureMessage": "",
      "failedDecisionId": "",
      "decisionRequirementsId": "force_users",
      "decisionRequirementsKey": 2251799813685264,
      "decisionId": "force_user",
      "decisionName": "Which force user?",
      "decisionKey": 2251799813685266,
      "bpmnProcessId": "force-user",
      "processDefinitionKey": 2251799813685268,
      "processInstanceKey": 2251799813685270,
      "elementInstanceKey": 2251799813685274,
      "elementId": "Activity_1sl5qf7"
    },
    "key": 2251799813685277,
    "timestamp": 1647429371592,
    "sourceRecordPosition": 46,
    "intent": "EVALUATED",
    "rejectionType": "NULL_VAL",
    "rejectionReason": "",
    "brokerVersion": "1.4.0",
    "valueType": "DECISION_EVALUATION",
    "recordType": "EVENT",
    "position": 50
  },
  "fields": {
    "value.decisionKey": [
      2251799813685266
    ],
    "value.evaluatedDecisions.decisionOutput": [
      "\"Jedi\"",
      "\"Obi-Wan Kenobi\""
    ],
    "value.evaluatedDecisions.decisionVersion": [
      4,
      5
    ],
    "sourceRecordPosition": [
      46
    ],
    "value.decisionRequirementsId": [
      "force_users"
    ],
    "value.evaluatedDecisions.decisionKey": [
      2251799813685265,
      2251799813685266
    ],
    "value.evaluatedDecisions.evaluatedInputs.inputName": [
      "",
      "",
      ""
    ],
    "rejectionType": [
      "NULL_VAL"
    ],
    "value.evaluatedDecisions.matchedRules.evaluatedOutputs.outputValue": [
      "\"Jedi\"",
      "\"Obi-Wan Kenobi\""
    ],
    "value.decisionVersion": [
      5
    ],
    "value.evaluatedDecisions.evaluatedInputs.inputId": [
      "Input_1",
      "InputClause_0qnqj25",
      "InputClause_0k64hys"
    ],
    "valueType": [
      "DECISION_EVALUATION"
    ],
    "value.decisionId": [
      "force_user"
    ],
    "value.elementId": [
      "Activity_1sl5qf7"
    ],
    "key": [
      2251799813685277
    ],
    "timestamp": [
      "2022-03-16T11:16:11.592Z"
    ],
    "value.processInstanceKey": [
      2251799813685270
    ],
    "value.evaluatedDecisions.evaluatedInputs.inputValue": [
      "\"blue\"",
      "\"Jedi\"",
      "185"
    ],
    "value.elementInstanceKey": [
      2251799813685274
    ],
    "value.decisionRequirementsKey": [
      2251799813685264
    ],
    "value.evaluatedDecisions.matchedRules.ruleId": [
      "DecisionRule_0zumznl",
      "DecisionRule_0uin2hk"
    ],
    "value.decisionOutput": [
      "\"Obi-Wan Kenobi\""
    ],
    "value.processDefinitionKey": [
      2251799813685268
    ],
    "partitionId": [
      1
    ],
    "value.evaluatedDecisions.matchedRules.evaluatedOutputs.outputName": [
      "",
      ""
    ],
    "recordType": [
      "EVENT"
    ],
    "value.decisionName": [
      "Which force user?"
    ],
    "value.failedDecisionId": [
      ""
    ],
    "brokerVersion": [
      "1.4.0"
    ],
    "intent": [
      "EVALUATED"
    ],
    "value.evaluatedDecisions.matchedRules.evaluatedOutputs.outputId": [
      "Output_1",
      "OutputClause_0hhe1yo"
    ],
    "value.bpmnProcessId": [
      "force-user"
    ],
    "value.evaluatedDecisions.decisionName": [
      "Jedi or Sith",
      "Which force user?"
    ],
    "value.evaluatedDecisions.matchedRules.ruleIndex": [
      1,
      2
    ],
    "value.evaluatedDecisions.decisionId": [
      "jedi_or_sith",
      "force_user"
    ],
    "value.evaluatedDecisions.decisionType": [
      "DECISION_TABLE",
      "DECISION_TABLE"
    ],
    "value.evaluationFailureMessage": [
      ""
    ],
    "position": [
      50
    ],
    "rejectionReason": [
      ""
    ]
  }
}

[korthout]

Hiya @pihme, would you be willing to review this PR? If you want I can provide you with an intro to DMN in Zeebe. It's also fine if you'd rather someone else review. There's no need to rush this.

[pihme]

Saving comments; will continue after we had a chance to talk about it

[pihme]

LGTM 🏷️

[korthout]

I'm postponing merging this until it is clear whether Operate needs Zeebe to provide input/output names in the same way Modeler shows them.

[korthout]

@pihme To accommodate Operate, Zeebe now applies some logic to determine the name of evaluated inputs/outputs. Please have another look.

[pihme]

🎉 Looks good to me!

(One optional suggestion)

[korthout]

bors merge

[ghost]

Canceled.

[korthout]

bors merge

[ghost]

Timed out.

[korthout]

bors merge

[ghost]

Build failed (retrying...):

• continuous-integration/jenkins/branch

[ghost]

Build failed:

• continuous-integration/jenkins/branch

[korthout]

Bors merge

[ghost]

Build failed:

• continuous-integration/jenkins/branch

[korthout]

@pihme It seems there were some tests failing. I've adjusted the tests and updated the PR description to make it clear what this PR changes. Please have again another look 🙇

[pihme]

lgtm

[korthout]

bors merge

[ghost]

Build succeeded:

• Run smoke tests on windows-2022
• continuous-integration/jenkins/branch
• Run smoke tests on ubuntu-latest