UI: Show an empty object for object params with no value

[arose26]

FieldObject renders the JSON editor for params whose declared type is object — FieldSelector routes arrays to FieldStringArray, FieldAdvancedArray and FieldMultiSelect, so an array never reaches it. It nonetheless falls back to an empty array when the param has no value:

value={JSON.stringify(param.value ?? [], undefined, 2)}

So a param declared as an object but left unset opens the trigger form's editor showing [], and anyone editing it starts from the wrong JSON literal for the field's declared type.

The submitted conf is built from param.value rather than the editor text, so an untouched field still submits null — this is about what the user is shown and edits from, not about the value sent when the field is left alone.

related: #55213

Tests

Adds FieldObject.test.tsx covering both branches of the fallback — a param with no value, and one with an existing value. The first fails before this change (Expected {} / Received []) and passes after.

pnpm lint (eslint + tsc) is clean and the full ui suite passes — 935 tests across 121 files.

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Was generative AI tooling used to co-author this PR?

• Yes — Claude Code (Opus 5)

Generated-by: Claude Code (Opus 5) following the guidelines

[boring-cyborg]

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[choo121600]

Thanks for the contribution!
Could you also attach screenshots showing the UI before and after the changes?
this would be helpful for reviewers to better understand the changes :)

[arose26]

Thanks for the review — screenshots below.

Both show the trigger form's Run Parameters section for a DAG param declared as type: ["object", "null"] that has not been given a value. Only the one line in FieldObject.tsx differs between them.

Before — the editor opens on [], an array literal, for a param whose declared type is object:

After — it opens on {}, matching the declared type:

The rest of the field is unchanged: same label, same description, same editor.

For transparency about how these were produced: rather than stand up a full Airflow instance, I rendered the real FlexibleForm in a local Vite page, mounted the same way ConfigForm mounts it in the trigger dialog (same Accordion.Root props, no noAccordion), seeded with a single object param. So the accordion section, the Row layout and the Monaco editor are the actual components with the actual styling — nothing mocked or redrawn. What is not pictured is the surrounding dialog chrome, since that comes from the modal rather than from this field.

[boring-cyborg]

Awesome work, congrats on your first merged pull request! You are invited to check our Issue Tracker for additional contributions.

[github-actions]

Backport successfully created: v3-3-test

Note: As of Merging PRs targeted for Airflow 3.X
the committer who merges the PR is responsible for backporting the PRs that are bug fixes (generally speaking) to the maintenance branches.

In matter of doubt please ask in #release-management Slack channel.

Status	Branch	Result
✅	v3-3-test