fix(desktop): remove duplicate HTML5 backend from v2 Workspace

[Kitenite]

Summary

• Removes the nested DndProvider from packages/panes Workspace component that conflicted with the one in the authenticated layout, causing "Cannot have two HTML5 backends at the same time" when v2 feature flag is disabled
• Removes unused react-dnd-html5-backend dependency from @superset/panes — child components (TabItem, TabBar, Pane, PaneHeader) use useDrag/useDrop hooks which consume the existing DndProvider context from the layout

Test plan

• Disable v2 feature flag and verify no "Cannot have two HTML5 backends" error
• Verify tab drag-and-drop reordering still works in v2 workspace
• Verify pane drag-and-drop still works in v2 workspace

---

Summary by cubic

Removed the duplicate HTML5 DnD backend from Workspace to reuse the app-level provider and stop the “Cannot have two HTML5 backends” error when the v2 flag is off; bulk tab close actions now await async closeTab and DnD still works. Updated @superset/panes README to document that Workspace must be wrapped in a single app-level DndProvider.

• Bug Fixes

  • Removed nested DndProvider/HTML5Backend from packages/panes/src/react/components/Workspace/Workspace.tsx to use the authenticated layout provider.
  • onCloseAllTabs and onCloseOtherTabs now await async closeTab to avoid race conditions and inconsistent state.

• Dependencies

  • Removed react-dnd-html5-backend from @superset/panes.

^{Written for commit a8af7cb. Summary will update on new commits.}

Summary by CodeRabbit

• Refactor

  • Workspace no longer provides an internal drag-and-drop context; child components must be wrapped by an external DnD provider.
  • Tab closing now processes each tab sequentially (awaits each close), changing the timing and ordering of multi-tab close actions.

• Chores

  • Removed the package's declared drag-and-drop backend dependency.

• Documentation

  • Added usage notes explaining the external DnD provider requirement.

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: a0a55565-46f4-4f58-85bb-5856b2523055

📥 Commits

Reviewing files that changed from the base of the PR and between 256353c and a8af7cb.

📒 Files selected for processing (2)

• packages/panes/README.md
• packages/panes/src/react/components/Workspace/Workspace.tsx

---

📝 Walkthrough

Walkthrough

Removed the bundled react-dnd HTML5 backend and the internal DnDProvider wrapper from Workspace; documentation updated to require consumers to provide a DndProvider when using . (50 words)

Changes

Cohort / File(s)	Summary
Dependency Removal packages/panes/package.json	Removed the react-dnd-html5-backend dependency entry.
Workspace component packages/panes/src/react/components/Workspace/Workspace.tsx	Removed DndProvider/HTML5Backend wrapper and import; TabBar and tab contents render outside an internal DnDProvider; onCloseOtherTabs/onCloseAllTabs converted to async/await per-tab close.
Documentation packages/panes/README.md	Added "Drag-and-Drop" section documenting that consumers must wrap <Workspace> with a DndProvider (e.g., HTML5Backend).

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Possibly related PRs

• fix(desktop): remove duplicate HTML5 backend from v2 Workspace #3174 — Removes nested DndProvider/HTML5 backend from Workspace and drops the react-dnd-html5-backend dependency (same code paths).

Poem

🐰 I hopped in code to lend a paw,
I nudged the provider from the draw,
Tell the caller, "Bring your net,"
Tabs now dance without a let,
A tiny hop — my whiskers thaw.

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the main change: removing a duplicate HTML5 backend from the v2 Workspace component.
Description check	✅ Passed	The PR description is comprehensive and well-structured, covering the problem, solution, dependencies changed, and test plan with clear verification steps.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch remove-duplicate-html5-backend

---

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[greptile-apps]

Greptile Summary

This PR fixes a runtime crash — "Cannot have two HTML5 backends at the same time" — by removing the redundant DndProvider/HTML5Backend wrapper that Workspace was adding on top of the singleton DndProvider already supplied by AuthenticatedLayout.

Key changes:

• Workspace.tsx: removes the DndProvider + HTML5Backend wrapper; child components (TabItem, TabBar, Pane, PaneHeader) already consume useDrag/useDrop from the existing React DnD context provided by the layout, so drag-and-drop behaviour is unchanged.
• packages/panes/package.json + bun.lock: removes the now-unused react-dnd-html5-backend dependency; react-dnd itself is correctly retained for the hooks.

Architecture note: @superset/panes is a private package consumed exclusively within the _authenticated route tree, where the singleton dragDropManager (created in renderer/lib/dnd.ts) is always present. The implicit requirement for a parent DndProvider is therefore safe in the current codebase, though worth capturing in package documentation if the package is ever made reusable outside this layout.

Confidence Score: 5/5

• Safe to merge — the change is a targeted, well-scoped removal of a duplicate DnD provider with no logic side-effects.
• The fix is minimal and correct: the Workspace component's child hooks (useDrag/useDrop) continue to work because the singleton DndProvider from AuthenticatedLayout is always present in the component tree. The removed react-dnd-html5-backend dependency was the only new import, and it is gone cleanly from both package.json and bun.lock. No test changes are required since the store tests are unaffected. The @superset/panes package is private and its sole consumer lives inside the authenticated layout, so the implicit DnD context dependency is bounded and safe.
• No files require special attention.

Important Files Changed

Filename	Overview
packages/panes/src/react/components/Workspace/Workspace.tsx	Removes the duplicate DndProvider/HTML5Backend wrapper; drag-and-drop hooks in child components continue to consume the singleton DndProvider supplied by AuthenticatedLayout.
packages/panes/package.json	Removes the now-unused react-dnd-html5-backend dependency; react-dnd is correctly retained for useDrag/useDrop hooks.
bun.lock	Lock-file updated to reflect the removed react-dnd-html5-backend entry for @superset/panes.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A["AuthenticatedLayout\n(layout.tsx)"] -->|"DndProvider\nmanager=dragDropManager\n(HTML5Backend singleton)"| B["Outlet / Child Routes"]
    B --> C["V2WorkspacePage\n(page.tsx)"]
    C --> D["Workspace\n(@superset/panes)"]
    D --> E["TabBar"]
    D --> F["Tab"]
    E --> G["TabItem\n(useDrag/useDrop)"]
    F --> H["Pane / PaneHeader\n(useDrag/useDrop)"]

    style A fill:#4ade80,color:#000
    style D fill:#60a5fa,color:#000

    subgraph "BEFORE (conflicting)"
        OLD_D["Workspace\n(DndProvider + HTML5Backend)"]
        OLD_D -->|"❌ Second HTML5Backend\ncauses runtime error"| OLD_PARENT["Parent DndProvider\nalready active"]
    end

    subgraph "AFTER (this PR)"
        NEW_D["Workspace\n(no DndProvider)"]
        NEW_D -->|"✅ Consumes parent\nDndProvider context"| NEW_PARENT["AuthenticatedLayout\nDndProvider"]
    end

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[cubic-dev-ai]

No issues found across 3 files

[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@packages/panes/src/react/components/Workspace/Workspace.tsx`:
- Around line 43-51: The bulk tab-close handlers (onCloseOtherTabs and
onCloseAllTabs) call the async closeTab for each tab without awaiting, causing
concurrent onBeforeCloseTab flows; change these callbacks to async and iterate
with a for...of loop awaiting closeTab(tab.id) for each tab (use the existing
tabs array and closeTab function), ensuring each close completes before
proceeding to the next to avoid race conditions in validation/store updates.
- Around line 38-77: The bulk-close callbacks currently call the async function
closeTab without awaiting it in onCloseOtherTabs and onCloseAllTabs, which can
produce overlapping operations and unhandled rejections from onBeforeCloseTab;
make those callbacks async and either await each closeTab sequentially (for
predictable ordering) or collect promises and await Promise.allSettled to handle
errors; update the onCloseOtherTabs and onCloseAllTabs handlers to await
closeTab for each tab and add basic error handling (try/catch or allSettled) so
rejections from onBeforeCloseTab are handled gracefully.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 839bf85f-67d8-4985-b8a0-e30281f8b8a7

📥 Commits

Reviewing files that changed from the base of the PR and between 7599ace and d7d6ad7.

⛔ Files ignored due to path filters (1)

• bun.lock is excluded by !**/*.lock

📒 Files selected for processing (2)

• packages/panes/package.json
• packages/panes/src/react/components/Workspace/Workspace.tsx

💤 Files with no reviewable changes (1)

• packages/panes/package.json