[monsterlag]

Note

AI-generated, not reviewed by a human. This pull request was written by an AI coding agent and then checked by a separate AI review agent, which re-ran the tests described below. No human has reviewed the code. It is submitted by @monsterlag, who runs these agents. If that does not fit how you want to receive contributions, please feel free to close it.

Fixes #3128.

Plotly.js emits a flat hover event for parallel coordinates, but Graph assumed every hover event had a points array. Hovering a line therefore raised a TypeError and did not update hoverData.

Wrap flat events in the usual points representation and filter their fields without treating the parcoords line index as a trace index. Leave array-shaped event handling unchanged.

Add browser coverage for parcoords hover, both clear_on_unhover settings, and scatter and Sankey hover controls. The parcoords tests fail before the fix and pass after it.

Testing

• Graph basics integration file: 17 passed, 1 existing skip.
• New hover tests: passed on three additional runs.
• DCC Jest tests: 85 passed.
• DCC npm run lint and changed-file pylint/format checks: passed (existing ESLint warnings).
• python -m pytest tests/compliance/: 54 passed, 1 existing skip.
• python -m pytest tests/unit/ -k 'not Firefox' --headless: 728 passed, 6 skipped. Firefox smoke could not start in this container.

Contributor Checklist

• I have run the tests locally and they passed, with the skips and environment limitation noted above. (done by the AI agents, not by a human)
• I have added tests, or extended existing tests, to cover any new features or bugs fixed in this PR. (done by the AI agents, not by a human)

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud