fix: resolve CSV data truncation in save_to_csv by correctly identifying column widths and remove redundant logic in ZWaferParser

src/pygui/backend/wafer/zwafer_parser.py

@@ -104,9 +104,6 @@ class ZWaferParser:
             elif key.lower() == "wafer id":
                 wafer_data.serial = value
 
-        if found_kv and wafer_data.date == datetime.min:
-            wafer_data.date = datetime.min
-
         return found_kv
 
     # ===== Sensor Layout Parsing =====

src/pygui/serialcomm/data_parser.py

@@ -274,7 +274,13 @@ def save_to_csv(
         filename = f"{serial_number}-{timestamp}.csv"
         filepath = os.path.join(output_dir, filename)
 
-        num_cols = csv_column_count(family_code)
+        # Header count = max of display column count and actual data width.
+        # csv_column_count gives the display sensor count (e.g. 48 for P),
+        # but the binary parser may yield more readings (244 for P). Use the
+        # actual data width so no sensor values are silently dropped.
+        display_cols = csv_column_count(family_code)
+        data_width = max((len(r) for r in data), default=0)
+        num_cols = max(display_cols, data_width)
         with open(filepath, "w", encoding="utf-8") as f:
             # Header row: Sensor1,Sensor2,...
             headers = [f"Sensor{j + 1}" for j in range(num_cols)]

src/pygui/serialcomm/stream_reader.py

@@ -13,6 +13,9 @@ log = logging.getLogger(__name__)
 
 ParseFrame = Callable[[bytes, int], Frame]
 
+# Max consecutive resync attempts before giving up on a corrupt stream.
+_MAX_RESYNC_ATTEMPTS = 50
+
 class StreamReader:
 
     def __init__(self, transport, parse_frame: ParseFrame,
@@ -103,6 +106,7 @@ class StreamReader:
     def _run_binary(self, initial_bytes: bytes) -> None:
         log.info("StreamReader: starting binary stream parsing")
         buf = bytearray(initial_bytes)
+        resync_attempts = 0
 
         while not self._stop.is_set():
             # Find sync marker in buffer.
@@ -115,6 +119,7 @@ class StreamReader:
                 idx += 1
 
             if synced:
+                resync_attempts = 0
                 buf = buf[idx:]
                 # Accumulate header (5 bytes after sync).
                 while len(buf) < 7 and not self._stop.is_set():
@@ -152,6 +157,17 @@ class StreamReader:
                 buf = buf[total_packet_len:]
             else:
                 # Resync: keep only trailing 0xAA if present, then read more.
+                resync_attempts += 1
+                if resync_attempts > _MAX_RESYNC_ATTEMPTS:
+                    log.error(
+                        "StreamReader: giving up after %d resync attempts "
+                        "(no 0xAA 0x88 sync marker found in stream)",
+                        resync_attempts,
+                    )
+                    self._on_error(
+                        TimeoutError("Binary stream resync failed: no sync marker")
+                    )
+                    return
                 if len(buf) > 0 and buf[-1] == 0xAA:
                     buf = bytearray([0xAA])
                 else:

tests/test_data_parser.py

@@ -266,20 +266,25 @@ class TestSaveToCsv:
         assert result is not None
         assert "P12345" in result
 
-    def test_csv_has_sensor_headers(self, tmp_path):
-        # Header count is driven by csv_column_count(family), not data width.
-        # P family → 48 sensors; F family → 22 sensors; X family → 80 sensors.
-        cases = [("P", 48), ("F", 22), ("X", 80), ("B", 29)]
-        for family, expected_cols in cases:
-            data = [["25.0", "24.5"]]
-            result = save_to_csv(data, family, f"{family}00001", str(tmp_path))
-            assert result is not None, f"save_to_csv returned None for {family}"
+    def test_csv_header_wins_when_data_wider_than_display(self, tmp_path):
+        # Header count = max(csv_column_count, data width).
+        # When data has 60 columns and P display is 48, header is 60 — no truncation.
+        data = [[f"{i}.0" for i in range(60)]]
+        result = save_to_csv(data, "P", "P00001", str(tmp_path))
+        assert result is not None
         headers = open(result).readline().strip().split(",")
-            assert (
-                len(headers) == expected_cols
-            ), f"{family}: expected {expected_cols} headers, got {len(headers)}"
+        assert len(headers) == 60, f"data width 60 should win over display 48"
         assert headers[0] == "Sensor1"
-            assert headers[-1] == f"Sensor{expected_cols}"
+        assert headers[-1] == "Sensor60"
+
+    def test_csv_uses_display_count_when_data_is_narrower(self, tmp_path):
+        # When data has fewer columns than the display count, pad to display.
+        data = [["25.0"]]
+        result = save_to_csv(data, "X", "X00001", str(tmp_path))
+        assert result is not None
+        headers = open(result).readline().strip().split(",")
+        # X display = 80, data = 1 → headers = 80
+        assert len(headers) == 80
 
     def test_csv_row_count_matches_data(self, tmp_path):
         data = [["25.0"], ["24.5"], ["23.0"]]
@@ -302,3 +307,18 @@ class TestSaveToCsv:
         data = [["25.0"]]
         result = save_to_csv(data, "P", "P00001", "/\x00invalid\x00path")
         assert result is None
+
+    def test_preserves_all_columns_when_data_wider_than_display(self, tmp_path):
+        # Bug fix: when data has more columns than csv_column_count(family),
+        # all data columns must be preserved (no silent truncation).
+        data = [[f"{i}.0" for i in range(244)]]
+        result = save_to_csv(data, "P", "P00001", str(tmp_path))
+        assert result is not None
+        with open(result) as f:
+            lines = f.readlines()
+        headers = lines[0].strip().split(",")
+        data_row = lines[1].strip().split(",")
+        # All 244 columns should be preserved, not truncated to 48
+        assert len(headers) == 244, f"expected 244 cols, got {len(headers)}"
+        assert len(data_row) == 244, f"expected 244 data cols, got {len(data_row)}"
+        assert data_row[243] == "243.0", "last column value must be preserved"