fix: don't grey out streaming output in grid and slides layouts by mscolnick · Pull Request #10094 · marimo-team/marimo

mscolnick · 2026-07-07T19:40:58Z

The grid and slides renderers marked a cell's output as stale for the entire
time the cell was running by deriving stale from outputIsLoading(status).
That greys out output even when it is actively streaming (e.g. a spinner via
mo.status.spinner / mo.output.replace), which is exactly the run/app-view
symptom reported. The vertical layout avoids this by using outputIsStale,
whose outputReceivedWhileRunning exemption keeps freshly-streamed output
un-greyed — the grid and slide renderers never adopted it.

Use outputIsStale (matching vertical-layout, edited=false) in GridCell and the
Slide output component, threading interrupted/staleInputs/runStartTimestamp
through all call sites (three GridCell sites; five Slide sites across minimap,
slide-cell-view, and reveal-component). Add a render test asserting streaming
output is not greyed while a queued cell's output still is.

Fixes #1587

The grid and slides renderers marked a cell's output as stale for the entire time the cell was running by deriving `stale` from outputIsLoading(status). That greys out output even when it is actively streaming (e.g. a spinner via mo.status.spinner / mo.output.replace), which is exactly the run/app-view symptom reported. The vertical layout avoids this by using outputIsStale, whose `outputReceivedWhileRunning` exemption keeps freshly-streamed output un-greyed — the grid and slide renderers never adopted it. Use outputIsStale (matching vertical-layout, edited=false) in GridCell and the Slide output component, threading interrupted/staleInputs/runStartTimestamp through all call sites (three GridCell sites; five Slide sites across minimap, slide-cell-view, and reveal-component). Add a render test asserting streaming output is not greyed while a queued cell's output still is. Fixes #1587

vercel · 2026-07-07T19:41:01Z

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Project	Deployment	Actions	Updated (UTC)
marimo-docs	Ready	Preview, Comment	Jul 8, 2026 3:09pm

Copilot

Pull request overview

This PR fixes a UI regression in non-vertical layouts (grid + slides) where cell output was being marked stale (greyed out) for the entire time a cell was running, even when the output was actively streaming updates. It aligns grid/slides behavior with the vertical layout by using outputIsStale() (which exempts “output received while running”) instead of deriving stale directly from outputIsLoading().

Changes:

Switch stale computation in slides and grid layouts from outputIsLoading(status) to outputIsStale({ ...runtimeFields }, edited=false).
Thread interrupted, staleInputs, and runStartTimestamp through all Slide and GridCell call sites that need accurate staleness.
Add a slides render test asserting streaming output is not greyed while running, while queued output remains greyed.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
frontend/src/components/slides/slide.tsx	Compute `stale` via `outputIsStale()` so streaming output isn’t greyed during runs.
frontend/src/components/slides/slide-cell-view.tsx	Pass `interrupted`, `staleInputs`, `runStartTimestamp` into `Slide`.
frontend/src/components/slides/reveal-component.tsx	Thread the additional runtime fields through `Slide` usage in reveal views.
frontend/src/components/slides/minimap.tsx	Thread the additional runtime fields through thumbnail `Slide` rendering.
frontend/src/components/slides/tests/slide.test.tsx	Add regression tests for issue #1587 stale/streaming behavior.
frontend/src/components/editor/renderers/grid-layout/grid-layout.tsx	Update `GridCell` to use `outputIsStale()` and plumb required fields through call sites.

cubic-dev-ai

No issues found across 6 files

Architecture diagram

sequenceDiagram
    participant User as User
    participant Renderer as Grid/Slide Renderer
    participant CellState as Cell Runtime State
    participant StaleFunc as outputIsStale()
    participant OutputArea as OutputArea Component
    participant DOM as DOM (CSS class)

    Note over Renderer, StaleFunc: CHANGED: In GridCell & Slide, replace outputIsLoading with outputIsStale

    Renderer->>CellState: read status, output, interrupted, staleInputs, runStartTimestamp
    Renderer->>StaleFunc: call(state, edited=false)
    Note over StaleFunc: logic: check if status is "running" or "queued", then apply<br/>outputReceivedWhileRunning exemption

    alt Cell running with streaming output (output.timestamp > runStartTimestamp)
        StaleFunc-->>Renderer: stale = false
        Renderer->>OutputArea: stale={false}
        OutputArea->>DOM: no "marimo-output-stale" class
        Note over DOM: Output remains bright, not greyed out
    else Cell queued (no exemption)
        StaleFunc-->>Renderer: stale = true
        Renderer->>OutputArea: stale={true}
        OutputArea->>DOM: adds "marimo-output-stale" class
        Note over DOM: Output greyed out (old queued behavior preserved)
    end

    Note over Renderer, OutputArea: Previously: outputIsLoading(status) always returned true for "running",<br/>so streaming output was incorrectly greyed out. Now matches vertical layout.

_{Re-trigger cubic}

Per review, compute outputIsStale(cell, false) at the call sites and pass a single stale boolean into GridCell and Slide instead of threading interrupted, staleInputs, and runStartTimestamp into each. Pure refactor — same computed value, no behavior change.

cubic-dev-ai

1 issue found across 6 files (changes from recent commits).

Prompt for AI agents (unresolved issues)


Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="frontend/src/components/slides/__tests__/slide.test.tsx">

<violation number="1" location="frontend/src/components/slides/__tests__/slide.test.tsx:22">
P3: The streaming-output regression can reappear in the slides renderers without this test failing, because the test now bypasses the stale calculation by passing `stale={false}`/`stale={true}` directly into the leaf `Slide`. Consider adding or restoring a render-level case through a slides caller (or otherwise computing `stale` from a runtime cell with `output.timestamp > runStartTimestamp`) so the test fails if a call site goes back to `outputIsLoading(status)`.

(Based on your team's feedback about preserving targeted regression coverage for bug fixes.) [FEEDBACK_USED]</violation>
</file>

_{Tip: Review your code locally with the cubic CLI to iterate faster.

Re-trigger cubic}

cubic-dev-ai · 2026-07-08T15:12:46Z

+describe("Slide", () => {
+  it("does not grey out the output when stale is false", () => {
+    const { container } = render(
+      <Slide cellId={cellId} status="running" output={output} stale={false} />,


P3: The streaming-output regression can reappear in the slides renderers without this test failing, because the test now bypasses the stale calculation by passing stale={false}/stale={true} directly into the leaf Slide. Consider adding or restoring a render-level case through a slides caller (or otherwise computing stale from a runtime cell with output.timestamp > runStartTimestamp) so the test fails if a call site goes back to outputIsLoading(status).

(Based on your team's feedback about preserving targeted regression coverage for bug fixes.)

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At frontend/src/components/slides/__tests__/slide.test.tsx, line 22: <comment>The streaming-output regression can reappear in the slides renderers without this test failing, because the test now bypasses the stale calculation by passing `stale={false}`/`stale={true}` directly into the leaf `Slide`. Consider adding or restoring a render-level case through a slides caller (or otherwise computing `stale` from a runtime cell with `output.timestamp > runStartTimestamp`) so the test fails if a call site goes back to `outputIsLoading(status)`. (Based on your team's feedback about preserving targeted regression coverage for bug fixes.) </comment> <file context> @@ -3,52 +3,31 @@ - + it("does not grey out the output when stale is false", () => { + const { container } = render( + <Slide cellId={cellId} status="running" output={output} stale={false} />, + ); expect(container.querySelector(".marimo-output-stale")).toBeNull(); </file context>

Copilot AI review requested due to automatic review settings July 7, 2026 19:40

Copilot started reviewing on behalf of mscolnick July 7, 2026 19:41 View session

mscolnick requested a review from Light2Dark July 7, 2026 19:41

vercel Bot deployed to Preview July 7, 2026 19:43 View deployment

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cubic-dev-ai Bot reviewed Jul 7, 2026

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clean up

8305a00

vercel Bot deployed to Preview July 7, 2026 20:08 View deployment

Light2Dark added the bug Something isn't working label Jul 8, 2026

Light2Dark reviewed Jul 8, 2026

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Comment thread frontend/src/components/editor/renderers/grid-layout/grid-layout.tsx Outdated

vercel Bot deployed to Preview July 8, 2026 15:09 View deployment

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mscolnick merged commit 83c8db8 into main Jul 8, 2026
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mscolnick deleted the fix/1587-grid-slides-output-stale branch July 8, 2026 16:00

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fix: don't grey out streaming output in grid and slides layouts#10094

fix: don't grey out streaming output in grid and slides layouts#10094
mscolnick merged 3 commits into
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fix/1587-grid-slides-output-stale

mscolnick commented Jul 7, 2026

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vercel Bot commented Jul 7, 2026 •

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