[NFR]: Show the debug page in ADR apps #48

Summary

The package gives two things: the debug bar and the debug page (Phalcon\Debug). The debug page does not show in an ADR app, because ADR catches all exceptions before the debug page handler can run. Show the debug page in ADR apps, in development only.

Current state

• Debug::listen() uses set_exception_handler() (src/Debug.php:178).
• Phalcon\ADR\Application::handle() catches each Throwable and sends it to ErrorResponder. AbstractHttpFront::run() also catches each Throwable. The handler does not run for these exceptions.
• Debug::halt() throws RequestHalted (src/Debug.php:147), and onUncaughtLowSeverity() throws RuntimeWarning (src/Debug.php:253). In an Action, these also go to ErrorResponder, so the client gets a generic error response.
• ErrorResponder has a debug mode that gives the exception to the client. It does not give the debug page (backtrace, code fragments and superglobals).

Proposed direction

• Use the logger adapter from [NFR]: ADR exceptions source #47 to get the exception.
• Add a listener on application:afterHandle. When the logger received an exception, the response status is 500 or higher and the response is not JSON, the listener replaces the response content with Debug::renderHtml($exception).
• Keep the status that ErrorResponder set. A 404 from RouteNotFound keeps the application error page.
• The application opts in through a config key of the ADR service provider from [NFR]: Framework-neutral integration seam: boot and response injection without Mvc\Application #14.
• The listener runs only when the bar boots, and only for a client that AccessGate allows. The debug page shows sensitive data.

Notes

This design is not tested yet. Test it first in this issue.

Acceptance

• In an ADR app in development, an exception in an Action shows the debug page.
• Debug::halt() in an Action shows the debug page.
• The debug page is absent in a blocked environment and for a denied client.
• The debug page does not replace a JSON response or a 404 response.
• The bar is not injected into the debug page.
• The public API of Phalcon\Debug does not change.
• Tests pass with full coverage. phpcs and phpstan pass.

Depends on

• [NFR]: Framework-neutral integration seam: boot and response injection without Mvc\Application #14
• [NFR]: ADR exceptions source #47

Part of

#13