Enforce 'None' check in `communicate`
The bug was: The else branch was triggered for the empty string.
@@ -1164,7 +1164,7 @@ class Linter(metaclass=LinterMeta):
cmd[cmd.index('${file}')] = self.filename
elif '@' in cmd: # legacy SL3 crypto-identifier
cmd[cmd.index('@')] = self.filename
- elif not code:
+ elif code is None:
cmd.append(self.filename)
settings = self.get_view_settings()
