Describe the bug

When using the editorial workflow with GitLab (likely affects all backends), the "View Preview" button can show a stale production URL instead of the actual deploy preview URL — or instead of showing nothing at all.

Root cause

The DEPLOY_PREVIEW_FAILURE case in the deploys reducer only sets isFetching: false but does not clear the previous url and status:

case DEPLOY_PREVIEW_FAILURE: {
  const { collection, slug } = action.payload;
  state[`${collection}.${slug}`].isFetching = false;
  break;
}

This means the old state from a previous DEPLOY_PREVIEW_SUCCESS (or getDeploy for published entries) persists in the Redux store.

Reproduction flow

1. Open an existing published entry in the CMS editor
2. getDeploy runs → stores { url: "https://production-site.example.com/...", status: "SUCCESS" } in Redux
3. User saves → creates a cms/* branch → CI pipeline starts building a preview
4. componentDidUpdate triggers loadDeployPreview({ maxAttempts: 3 }) which polls for commit statuses
5. If no commit status exists yet (CI hasn't posted one), getDeployPreview returns null
6. DEPLOY_PREVIEW_FAILURE is dispatched → only sets isFetching: false
7. Old { status: "SUCCESS", url: "https://production-site.example.com/..." } remains in Redux
8. renderDeployPreviewControls sees status === 'SUCCESS' and renders the "View Preview" link pointing to the production URL, not the deploy preview

Expected behavior

When DEPLOY_PREVIEW_FAILURE fires, the stale url and status should be cleared so that no misleading "View Preview" link is shown:

case DEPLOY_PREVIEW_FAILURE: {
  const { collection, slug } = action.payload;
  const key = `${collection}.${slug}`;
  state[key].isFetching = false;
  state[key].url = undefined;
  state[key].status = undefined;
  break;
}

Workaround

We work around this by having our CI pipeline post a running commit status with target_url immediately when a cms/* branch is pushed. This ensures the first or second poll finds a status, causing DEPLOY_PREVIEW_SUCCESS with state: "OTHER" to overwrite the stale SUCCESS, which makes the toolbar show the "Check for Preview" refresh button instead of the misleading production link.

Applicable versions

• decap-cms 3.10.0
• GitLab backend
• publish_mode: editorial_workflow
• preview_context configured

Environment

• Browser: Chrome
• OS: macOS