feat: add Spinner.done() for checkmark transition

[allin2]

This pull request was authored by a coding agent.

Description

Adds Spinner.done(), which transitions a spinner from its loading animation to a checkmark. This resolves two TODOs by @akshayka:

1. Add a done() method that turns the spinner into a checkmark.
2. Transition a retained spinner to a completed state when its context exits successfully.

Changes

Python (marimo/_plugins/stateless/status/_progress.py)

• Add an _is_done flag to the _Progress base class.
• Add a thread-safe mark_done() method.
• Add Spinner.done() as the public convenience method.
• Serialize the optional done state for the frontend.
• Automatically mark retained spinners as done after successful context-manager exit.
• Clear retained spinners when the context exits with an exception, avoiding a false success state or an indefinitely loading spinner.

TypeScript (frontend/src/plugins/layout/ProgressPlugin.tsx)

• Add optional done state to the data interface and Zod validator.
• Render a green CheckCircle2Icon instead of the loading indicator when done=true.

Tests (tests/_plugins/stateless/status/test_progress.py)

• Verify done() updates completion state, title, and subtitle.
• Verify done() without arguments preserves the existing title and subtitle.
• Verify calling done() after close raises RuntimeError.
• Verify remove_on_exit=True clears the spinner.
• Verify successful exit with remove_on_exit=False transitions to done.
• Verify exceptional exit with remove_on_exit=False clears the spinner without marking it done.

Usage

# Manual completion
with mo.status.spinner("Loading ...") as spinner:
    data = expensive_function()
    spinner.done(title="Done!")

# Automatic completion after successful exit
with mo.status.spinner("Loading ...", remove_on_exit=False):
    data = expensive_function()

Validation

• tests/_plugins/stateless/status/test_progress.py: 21 passed.
• no-double-backticks-in-docstrings: passed.
• CLA Assistant: passed.
• pre-commit.ci: passed.

I have read the CLA Document and I hereby sign the CLA.

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Project	Deployment	Actions	Updated (UTC)
marimo-docs	Ready	Preview, Comment	Jun 22, 2026 9:04am

[github-actions]

All contributors have signed the CLA ✍️ ✅
_{Posted by the CLA Assistant Lite bot.}

[allin2]

I have read the CLA Document and I hereby sign the CLA

[matthieugraziani]

Thanks for the contribution! This is a clean and user-friendly enhancement that addresses both TODOs left in the codebase.

I particularly like:

The thread-safe implementation via mark_done()
The automatic transition when remove_on_exit=False
The frontend/backend consistency for the new done state
The comprehensive test coverage, including context manager behavior and error handling

A few points worth double-checking during review:

Ensure the serialized payload remains backward compatible for clients that may not yet recognize the done field.
Verify that repeated calls to done() are intentionally idempotent (or documented otherwise).
Consider whether future status states (success, warning, error) might benefit from a more generic state enum instead of a boolean flag.

Overall, the feature is well-scoped, resolves the referenced TODOs, and includes appropriate test coverage. Nice work!

[allin2]

@akshayka, could you please review this PR when you have a chance? It implements the two Spinner completion TODOs and handles exceptional context exits without showing a success state. Thank you.

[akshayka]

@allin2 do you have a use case for this? Feature requests need to be discussed with the team via a GitHub issue before submitting a PR for review

[Yasin197]

@allin2 - do you think if we had like 4 items in a workflow where each item ended in a check mark, we could see all 4 check marks in the UI?

[akshayka]

Closing due to lack of response