Core: Ensure telemetry is never triggered on initial load of checklist data

[ghengeveld]

What I did

Added a check to prevent triggering telemetry on initial load of checklist data from persistence.

Unfortunately, I was not able to reproduce the problem locally. However, the data suggests that telemetry is triggered when loading from persistence, because controls and viewports appear over-reported. These two items have very high completion rates despite normally requiring a manual user action (changing controls or switching viewports). As such, I want to eliminate the possibility by adding this extra guard.

Checklist for Contributors

Testing

The changes in this PR are covered in the following automated tests:

• stories
• unit tests
• integration tests
• end-to-end tests

Manual testing

Unfortunately it's unknown how to reproduce the original issue.

Documentation

• Add or update documentation reflecting your changes
• If you are deprecating/removing a feature, make sure to update
  MIGRATION.MD

Checklist for Maintainers

• When this PR is ready for testing, make sure to add ci:normal, ci:merged or ci:daily GH label to it to run a specific set of sandboxes. The particular set of sandboxes can be found in code/lib/cli-storybook/src/sandbox-templates.ts

• Make sure this PR contains one of the labels below:

  Available labels

  • bug: Internal changes that fixes incorrect behavior.
  • maintenance: User-facing maintenance tasks.
  • dependencies: Upgrading (sometimes downgrading) dependencies.
  • build: Internal-facing build tooling & test updates. Will not show up in release changelog.
  • cleanup: Minor cleanup style change. Will not show up in release changelog.
  • documentation: Documentation only changes. Will not show up in release changelog.
  • feature request: Introducing a new feature.
  • BREAKING CHANGE: Changes that break compatibility in some way with current major version.
  • other: Changes that don't fit in the above categories.

🦋 Canary release

This PR does not have a canary release associated. You can request a canary release of this pull request by mentioning the @storybookjs/core team here.

core team members can create a canary release here or locally with gh workflow run --repo storybookjs/storybook publish.yml --field pr=<PR_NUMBER>

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☁️ Nx Cloud last updated this comment at 2026-02-25 16:38:57 UTC

[coderabbitai]

📝 Walkthrough

Walkthrough

The PR modifies telemetry handling in the checklist utility by removing the dequal import and adding an early return guard that skips telemetry processing when loading from persistence during the initial load transition, preventing telemetry events from firing in this scenario.

Changes

Cohort / File(s)	Summary
Telemetry Guard Logic code/core/src/core-server/utils/checklist.ts	Removed dequal import and added early return condition that skips telemetry and state-diff processing when previousState.loaded is false, preventing onboarding telemetry from firing during initial persistence-based loading.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Possibly related PRs

• Checklist: Fix how state changes are reported and drop some completion restrictions #33217 — Both PRs modify telemetry handling in the same checklist utility file, with this PR adding an early return to skip telemetry on initial persistence load while the related PR alters telemetry event structure and emission logic.

✨ Finishing Touches

• 📝 Generate docstrings (stacked PR)
• 📝 Generate docstrings (commit on current branch)

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[coderabbitai]

🧹 Nitpick comments (1)

code/core/src/core-server/utils/checklist.ts (1)

87-90: Consider narrowing the guard to the explicit false → true transition.

The current condition !previousState.loaded skips telemetry for any state change where the previous state had loaded: false. In this codebase that only ever happens once (the initial setState call sets loaded: true), so the fix is correct today. However, if a future refactor ever drops the loaded: true assignment, this guard would silently swallow all telemetry without any obvious signal.

Tightening the condition to also assert state.loaded makes the intent precise:

💡 Proposed refinement

-      // Skip telemetry when loading from persistence (first transition to loaded: true)
-      if (!previousState.loaded) {
+      // Skip telemetry when loading from persistence (first transition to loaded: true)
+      if (!previousState.loaded && state.loaded) {
         return;
       }

🤖 Prompt for AI Agents

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

In `@code/core/src/core-server/utils/checklist.ts` around lines 87 - 90, The guard
currently returns whenever previousState.loaded is falsy, which is too broad;
change the check in checklist.ts to only skip telemetry on the explicit
false→true transition by testing both sides: return early only when
previousState.loaded === false && state.loaded === true (so reference the
previousState and state.loaded symbols and update that conditional accordingly).

🤖 Prompt for all review comments with AI agents

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

Nitpick comments:
In `@code/core/src/core-server/utils/checklist.ts`:
- Around line 87-90: The guard currently returns whenever previousState.loaded
is falsy, which is too broad; change the check in checklist.ts to only skip
telemetry on the explicit false→true transition by testing both sides: return
early only when previousState.loaded === false && state.loaded === true (so
reference the previousState and state.loaded symbols and update that conditional
accordingly).

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ℹ️ Review info

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📥 Commits

Reviewing files that changed from the base of the PR and between 10d1e88 and 3b7f67d.

📒 Files selected for processing (1)

• code/core/src/core-server/utils/checklist.ts