rfc6266: Improve error handling

qutebrowser/browser/webkit/http.py

@@ -47,12 +47,11 @@ def parse_content_disposition(reply):
         # os.path.basename later.
         try:
             value = bytes(reply.rawHeader(content_disposition_header))
-            log.rfc6266.debug("Parsing Content-Disposition: {!r}".format(
-                value))
+            log.rfc6266.debug("Parsing Content-Disposition: {value!r}")
             content_disposition = rfc6266.parse_headers(value)
             filename = content_disposition.filename()
-        except (UnicodeDecodeError, rfc6266.Error):
-            log.rfc6266.exception("Error while parsing filename")
+        except rfc6266.Error as e:
+            log.rfc6266.error(f"Error while parsing filename: {e}")
         else:
             is_inline = content_disposition.is_inline()
     # Then try to get filename from url

qutebrowser/browser/webkit/rfc6266.py

@@ -80,13 +80,16 @@ def parse_headers(content_disposition):
     # value won't get dismissed because of an unrelated ambiguity in the
     # filename parameter. But it does mean we occasionally give
     # less-than-certain values for some legacy senders.
-    content_disposition = content_disposition.decode('iso-8859-1')
+    try:
+        content_disposition = content_disposition.decode('iso-8859-1')
+    except UnicodeDecodeError as e:
+        raise Error(e)
 
     reg = email.headerregistry.HeaderRegistry()
     parsed = reg('Content-Disposition', content_disposition)
 
     if parsed.defects:
-        raise Error(parsed.defects)
+        raise Error(list(parsed.defects))
 
     return _ContentDisposition(disposition=parsed.content_disposition,
                                params=parsed.params)