Custom lookup example raises TypeError

[Jacob Walls]

On the forum I ​shared the TypeError I was getting when registering a custom lookup for a JSONField:

File models/lookups.py:13, in NotEqual.as_sql(self, compiler, connection)
     11 lhs, lhs_params = self.process_lhs(compiler, connection)
     12 rhs, rhs_params = self.process_rhs(compiler, connection)
---> 13 params = lhs_params + rhs_params
     14 return "%s <> %s" % (lhs, rhs), params

TypeError: can only concatenate list (not "tuple") to list

Since this problematic pattern is ​documented, we should either fix the documentation or fix the underlying reason it doesn't work. I haven't looked into whether there are backwards-compatible ways to do the latter.

Reproduction is just to follow the documented pattern and register it with a JSONField e.g. @JSONField.register_lookup, and then try to use it in an ORM query.