Add debugging to barcode detection to identify the issue

app.py

@@ -935,13 +935,17 @@ def parse_gs1(text: str) -> Optional[dict]:
     return out or None
 
 def _decode_zxing(pil: Image.Image) -> List[Dict[str,Any]]:
-    if not HAS_ZXING: return []
+    if not HAS_ZXING: 
+        print("ZXing not available")
+        return []
     arr = np.asarray(pil.convert("L"))
     out=[]
     hints = _zxing_hints_all()
     try:
         res = zxingcpp.read_barcodes(arr, hints=hints) if hints is not None else zxingcpp.read_barcodes(arr)
-    except Exception:
+        print(f"ZXing found {len(res) if res else 0} barcodes")
+    except Exception as e:
+        print(f"ZXing error: {e}")
         res = []
 
     for r in res or []:
@@ -1025,6 +1029,8 @@ def _decode_variants(pil: Image.Image) -> List[Dict[str,Any]]:
                 r["width"]  = int(round(r.get("width", 0) / scale))
                 r["height"] = int(round(r.get("height",0) / scale))
         return res
+    
+    print(f"Starting _decode_variants on image {pil.size}")
 
     # 1) Whole-page variants
     W,H = pil.size
@@ -1042,6 +1048,7 @@ def _decode_variants(pil: Image.Image) -> List[Dict[str,Any]]:
     for vimg, sc in variants:
         res = _decode_and_rescale(vimg, sc)
         if res:
+            print(f"Found {len(res)} barcodes in whole-page variant at scale {sc}")
             return res
 
     # 2) Tiled fallback (helps tiny or stacked GS1)
@@ -1067,7 +1074,9 @@ def _decode_variants(pil: Image.Image) -> List[Dict[str,Any]]:
                     # width/height already scaled
                     hits.append(r)
             if hits:
+                print(f"Found {len(hits)} barcodes in tiled fallback")
                 return hits
+    print("No barcodes found in any variant")
     return []
 
 def _pix_to_pil(pix) -> Image.Image:
@@ -1205,8 +1214,20 @@ def compare_pdfs(file_a, file_b):
         print(f"Spell check results - A: {len(misspell_a)} boxes, B: {len(misspell_b)} boxes")
 
         # Always attempt barcode scan. The PDF path uses ZXing-CPP / pyzbar / dmtx / cv2 if available.
-        bar_a, info_a = find_barcode_boxes_and_info_from_pdf(file_a.name, image_size=image_size)
-        bar_b, info_b = find_barcode_boxes_and_info_from_pdf(file_b.name, image_size=image_size)
+        try:
+            print(f"Starting barcode detection for file A: {file_a.name}")
+            bar_a, info_a = find_barcode_boxes_and_info_from_pdf(file_a.name, image_size=image_size)
+            print(f"Barcode detection A complete: {len(bar_a)} boxes, {len(info_a)} infos")
+            
+            print(f"Starting barcode detection for file B: {file_b.name}")
+            bar_b, info_b = find_barcode_boxes_and_info_from_pdf(file_b.name, image_size=image_size)
+            print(f"Barcode detection B complete: {len(bar_b)} boxes, {len(info_b)} infos")
+        except Exception as e:
+            print(f"Barcode detection error: {e}")
+            import traceback
+            traceback.print_exc()
+            bar_a, info_a = [], []
+            bar_b, info_b = [], []
 
         # Always enable CMYK analysis
         cmyk_entries = compute_cmyk_diffs(a, b, red_boxes)