Flaky tests caused by parallel jobs log parsing

[TWiStErRob]

Describe the bug
If one job starts a group, and another logs while that group is open, then the parser crashes with:

Cannot read properties of undefined (reading 'output')
TypeError: Cannot read properties of undefined (reading 'output')
    at OutputParser.parseStepOutput (node_modules/@kie/act-js/build/src/output-parser/output-parser.js:119:61)
    at OutputParser.parseOutput (node_modules/@kie/act-js/build/src/output-parser/output-parser.js:26:18)

this.groupMatrix[stepOutputMatcherResult[1]][length - 1].output += ...
                                                        ^ LHS undefined

this.groupMatrix[stepOutputMatcherResult[1]] === [], therefore length is 0, and ...[-1] === undefined.

To Reproduce

test("original", async () => {
    const contents = await fs.readFile("act.log");
    console.log(new OutputParser(contents.toString()).parseOutput());
});

act.log:

[Build/Tests            ] ⭐ Run Main Testing
[Build/Tests            ]   ❓  ::group::Unit Tests
[Build/Static Analysis  ] ⭐ Run Main Lint
[Build/Static Analysis  ]   | No problems found.
[Build/Tests            ]   | 1231 tests executed.
[Build/Tests            ]   ❓  ::endgroup::
[Build/Tests            ]   ❓  ::group::Integration Tests
[Build/Tests            ]   | 32 tests executed.
[Build/Tests            ]   ❓  ::endgroup::
[Build/Static Analysis  ]   ✅  Success - Main Linting
[Build/Tests            ]   ✅  Success - Main Testing

Expected behavior
"Just works".

Logs

Distilled real log focused on the issue

[Android Build/Unit Tests       ] 🚀  Start image=ghcr.io/catthehacker/ubuntu:act-latest
[Android Build/Android Lint     ] 🚀  Start image=ghcr.io/catthehacker/ubuntu:act-latest
[Android Build/Unit Tests       ] ⭐ Run Main Set up Android SDK.
[Android Build/Unit Tests       ]   🐳  docker cp src=/home/runner/.cache/act/android-actions-setup-android@v3/ dst=/var/run/act/actions/android-actions-setup-android@v3/
[Android Build/Android Lint     ] ⭐ Run Main Set up Android SDK.
[Android Build/Android Lint     ]   🐳  docker cp src=/home/runner/.cache/act/android-actions-setup-android@v3/ dst=/var/run/act/actions/android-actions-setup-android@v3/
[Android Build/Android Lint     ]   | [command]/root/.android/sdk/cmdline-tools/11.0/bin/sdkmanager tools
[Android Build/Unit Tests       ]   | [command]/root/.android/sdk/cmdline-tools/11.0/bin/sdkmanager tools
[Android Build/Android Lint     ]   | [command]/root/.android/sdk/cmdline-tools/11.0/bin/sdkmanager platform-tools
[Android Build/Android Lint     ]   ❓ add-matcher /run/act/actions/android-actions-setup-android@v3/matchers.json
[Android Build/Android Lint     ]   ✅  Success - Main Set up Android SDK.
[Android Build/Android Lint     ] ⭐ Run Main Set up Java for Project.
[Android Build/Android Lint     ]   🐳  docker cp src=/home/runner/.cache/act/actions-setup-java@v3/ dst=/var/run/act/actions/actions-setup-java@v3/
[Android Build/Android Lint     ]   ❓  ::group::Installed distributions
[Android Build/Android Lint     ]   | Resolved Java 17.0.9+9 from tool-cache
[Android Build/Unit Tests       ]   | [command]/root/.android/sdk/cmdline-tools/11.0/bin/sdkmanager platform-tools
[Android Build/Android Lint     ]   |   Path: /opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.9-9/x64
[Android Build/Android Lint     ]   ❓  ::endgroup::
[Android Build/Android Lint     ]   ✅  Success - Main Set up Java for Project.
[Android Build/Unit Tests       ]   ❓ add-matcher /run/act/actions/android-actions-setup-android@v3/matchers.json
[Android Build/Unit Tests       ]   ✅  Success - Main Set up Android SDK.

Additional context
Looking at output-parser.js, as far as I see .isPartOfGroup is handled on the parser level, but it should per-job.

[TWiStErRob]

Can you please release this?

[shubhbapna]

Done!