Astro Info

Astro                    v6.0.8
Vite                     v7.3.1
Node                     v24.14.0
System                   macOS (arm64)
Package Manager          npm
Output                   static
Adapter                  none
Integrations             none

If this issue only occurs in one browser, which browser is a problem?

Safari

Describe the Bug

When using <ClientRouter />, Safari's swipe back/forward gesture causes a visible flicker.

The browser already performs its own visual transition during the swipe, but ClientRouter starts another view transition via document.startViewTransition(), which briefly re-displays the pre-navigation
page.

This affects both macOS and iOS Safari.

What's the expected result?

Safari's swipe gesture should navigate without flicker. When the browser has already performed a visual transition (PopStateEvent.hasUAVisualTransition === true), ClientRouter should skip document.startViewTransition() and update the DOM directly.

Link to Minimal Reproducible Example

https://github.com/koji-1009/astro-swipe-back-repro

Participation

• I am willing to submit a pull request for this issue.