Build [v1.7.0] - GitGuard - Infrastructure Hardening

frontend/components/Scanner.tsx

@@ -25,6 +25,7 @@ export default function Scanner({ onScanSuccess, onOCRMatch, paused }: ScannerPr
   const [isSelecting, setIsSelecting] = useState(false);
   const [capturedImage, setCapturedImage] = useState<string | null>(null);
   const isBusy = useRef(false);
+  const isTransitioning = useRef(false); // Flag to track start/stop transitions
   const scannerId = "reader-container-unique";
 
   useEffect(() => {
@@ -33,11 +34,20 @@ export default function Scanner({ onScanSuccess, onOCRMatch, paused }: ScannerPr
     }
 
     const startScanner = async () => {
-      if (isBusy.current) return;
+      if (isBusy.current || isTransitioning.current) return;
       isBusy.current = true;
+      isTransitioning.current = true;
+
       try {
+        // If already scanning, we MUST stop it first
         if (html5QrCodeRef.current?.isScanning) {
-            await html5QrCodeRef.current.stop();
+            try {
+              await html5QrCodeRef.current.stop();
+            } catch (e) {
+              console.warn("Graceful stop failed, might be in transition:", e);
+              // If it's already in transition, we just return and wait for the next effect trigger
+              return;
+            }
         }
 
         const config = { 
@@ -85,6 +95,7 @@ export default function Scanner({ onScanSuccess, onOCRMatch, paused }: ScannerPr
         }
       } finally {
         isBusy.current = false;
+        isTransitioning.current = false;
       }
     };
 
@@ -94,11 +105,15 @@ export default function Scanner({ onScanSuccess, onOCRMatch, paused }: ScannerPr
 
     return () => {
       if (html5QrCodeRef.current?.isScanning) {
+        isTransitioning.current = true;
         html5QrCodeRef.current.stop()
             .then(() => {
                 setIsStarted(false);
             })
-            .catch(e => console.error("Stop failed", e));
+            .catch(e => console.error("Unmount stop failed", e))
+            .finally(() => {
+                isTransitioning.current = false;
+            });
       }
     };
   }, [paused, onScanSuccess]);