fix sse error handling if shop api error part 3

src/Controller/AskSseController.php

@@ -55,9 +55,9 @@ final readonly class AskSseController
                 'includeFullContext' => $includeFullContext,
                 'createdAt' => time(),
             ]);
-        } catch (\Throwable) {
+        } catch (\Throwable $e) {
             return new JsonResponse(
-                ['error' => 'Stream job could not be created.'],
+                ['error' => 'Stream job could not be created: ' . $this->formatThrowableForClient($e)],
                 Response::HTTP_INTERNAL_SERVER_ERROR
             );
         }
@@ -139,6 +139,7 @@ final readonly class AskSseController
         ?Response $cookieResponse
     ): void {
         $this->prepareStreamRuntime();
+        $this->registerStreamShutdownErrorHandler();
 
         if ($cookieResponse !== null) {
             foreach ($cookieResponse->headers->getCookies() as $cookie) {
@@ -167,13 +168,51 @@ final readonly class AskSseController
         } catch (\Throwable $e) {
             $this->sendEvent(
                 'error',
-                '❌ Stream abgebrochen: ' . $e->getMessage()
+                '❌ Stream abgebrochen: ' . $this->formatThrowableForClient($e)
             );
         }
 
         $this->sendEvent('done', '[DONE]');
     }
 
+    private function registerStreamShutdownErrorHandler(): void
+    {
+        register_shutdown_function(function (): void {
+            $error = error_get_last();
+
+            if ($error === null) {
+                return;
+            }
+
+            $fatalTypes = [E_ERROR, E_PARSE, E_CORE_ERROR, E_COMPILE_ERROR, E_USER_ERROR];
+
+            if (!in_array((int) ($error['type'] ?? 0), $fatalTypes, true)) {
+                return;
+            }
+
+            $message = sprintf(
+                '❌ Fataler Serverfehler: %s in %s:%s',
+                (string) ($error['message'] ?? 'unknown error'),
+                (string) ($error['file'] ?? 'unknown file'),
+                (string) ($error['line'] ?? '?')
+            );
+
+            $this->sendEvent('error', $message);
+            $this->sendEvent('done', '[DONE]');
+        });
+    }
+
+    private function formatThrowableForClient(\Throwable $e): string
+    {
+        $message = trim($e->getMessage());
+
+        if ($message === '') {
+            $message = $e::class;
+        }
+
+        return preg_replace('/\s+/u', ' ', $message) ?? $message;
+    }
+
     private function prepareStreamRuntime(): void
     {
         @set_time_limit(0);