Fail visual comparison when a captured document is an application error

wordpress.visual-compare accepts a navigation as successful when the server responds with HTTP 200 but renders an application/runtime fatal page. The command then screenshots the error document and emits pixel-comparison evidence as though it represented the requested site.

Reproduction

1. Serve an HTML response with status 200 whose body is a PHP fatal/error document.
2. Run wordpress.visual-compare against that URL.
3. Observe that navigation and screenshot capture complete without a page error.

Expected

Before DOM snapshot or screenshot creation, visual capture should fail closed when the main-document response is unsuccessful or the rendered document is a bounded, recognized runtime-error page. Failure evidence should include the role/URL, HTTP status, and bounded reason without persisting a screenshot as valid comparison evidence. Normal page copy containing words such as “error” must remain valid.

AI assistance

GPT-5.6 Sol via OpenCode reproduced the blind spot, traced it to the visual-compare capture boundary, and drafted this issue. Chris Huber remains responsible for the report and resulting changes.

Commencez à la frontière de capture de wordpress.visual-compare et reproduisez la réponse HTTP 200 PHP fatal/error documentée. Suivez la navigation à travers la création du DOM snapshot et de la capture d’écran ; le travail est terminé lorsque les documents runtime-error reconnus échouent en mode fail closed avec role, URL, status et une raison bornée, tandis que le texte normal de la page contenant « error » reste valide et qu’aucune capture d’écran invalide n’est persistée.