ArrayField can't use __contained_by or __overlap queries for CharField

[Joel Burton]

ArrayField's lookup.py uses the @> operator for __contains, the <@ operator for __contained_by, and the && operator for __overlap.

When the field uses CharField (Postgres' varchar()), __contains works, but __contained_by and __overlap do not, as Postgres does not define <@ and && operators for an array of varchar[] (it does for text[]).

__contains works because, in array.py, there is a custom lookup, "ArrayOverlap", the outputs a cast to cast the array query value to, say, "::varchar(10)[]"

If there are similar custom lookups for __contained_by and __overlap, these then work.

[Joel Burton]

Patch, along with tests

[Tim Graham]

Any chance you could send a pull request on GitHub? That makes it quite a bit easier to review the patch, run the tests, and merge it.

[Marc Tamlyn <marc.tamlyn@…>]

In 0ae94d0d3127adabcb0afaf32fd5dbe47d74cd57:

Fixes #24169 -- More arrayfield specific lookups.

varchar()[] cannot compare itself to text[]

Thanks to joelburton for the patch.

[Marc Tamlyn <marc.tamlyn@…>]

In c80b2144d22d29725cf4d584bfa9079dd35af064:

[1.8.x] Fixes #24169 -- More arrayfield specific lookups.

varchar()[] cannot compare itself to text[]

Thanks to joelburton for the patch.

Backport of 0ae94d0d31 from master