gw update: Do not rely on unique com.location field when reopening COM port.

In some cases Windows (with BitDefender) seems to obfuscate the location
and multiple COM ports alias to the same location string.

scripts/greaseweazle/tools/util.py

@@ -92,33 +92,38 @@ def with_drive_selected(fn, usb, args, *_args, **_kwargs):
 def valid_ser_id(ser_id):
     return ser_id and ser_id.upper().startswith("GW")
 
-def find_port(old_port=None):
-    # If we are reopening, and we know the location of the old port, require
-    # to match on location.
+def score_port(x, old_port=None):
+    score = 0
+    if x.manufacturer == "Keir Fraser" and x.product == "Greaseweazle":
+        score = 20
+    elif x.vid == 0x1209 and x.pid == 0x4d69:
+        # Our very own properly-assigned PID. Guaranteed to be us.
+        score = 20
+    elif x.vid == 0x1209 and x.pid == 0x0001:
+        # Our old shared Test PID. It's not guaranteed to be us.
+        score = 10
+    if score > 0 and valid_ser_id(x.serial_number):
+        # A valid serial id is a good sign unless this is a reopen, and
+        # the serials don't match!
+        if not old_port or not valid_ser_id(old_port.serial_number):
+            score = 20
+        elif x.serial_number == old_port.serial_number:
+            score = 30
+        else:
+            score = 0
     if old_port and old_port.location:
-        for x in serial.tools.list_ports.comports():
-            if x.location and x.location == old_port.location:
-                return x.device
-        raise serial.SerialException('Could not reopen Greaseweazle device')
-    # Score each serial port
+        # If this is a reopen, location field must match. A match is not
+        # sufficient in itself however, as Windows may supply the same
+        # location for multiple USB ports (this may be an interaction with
+        # BitDefender). Hence we do not increase the port's score here.
+        if not x.location or x.location != old_port.location:
+            score = 0
+    return score
+
+def find_port(old_port=None):
     best_score, best_port = 0, None
     for x in serial.tools.list_ports.comports():
-        score = 0
-        if x.manufacturer == "Keir Fraser" and x.product == "Greaseweazle":
-            score = 20
-        elif x.vid == 0x1209 and x.pid == 0x4d69:
-            # Our very own properly-assigned PID. Guaranteed to be us.
-            score = 20
-        elif x.vid == 0x1209 and x.pid == 0x0001:
-            # Our old shared Test PID. It's not guaranteed to be us.
-            score = 10
-        if score > 0 and valid_ser_id(x.serial_number):
-            if not old_port or not valid_ser_id(old_port.serial_number):
-                score = 20
-            elif x.serial_number == old_port.serial_number:
-                score = 30
-            else:
-                score = 0
+        score = score_port(x, old_port)
         if score > best_score:
             best_score, best_port = score, x
     if best_port: