Admin search_fields crashes for inherited model and __iexact lookup.

[Pavel Pančocha]

Hello everyone!

Let's have model Payer and we will create ExtendedPayer from it

class ExtendedPayer(Payer):
    ...

We create admin for ExtendedPayer and define search fields. We want to be able to filter by pk of Payer. So I would expect these to work the same:

class ExtendedPayerAdmin(ModelAdmin):
    ...
    search_fields = (
        "pk__iexact", ...
    )
    ...

class ExtendedPayerAdmin(ModelAdmin):
    ...
    search_fields = (
        "id__iexact", ...
    )
    ...

Guess what? The "id" variant works ok and the "pk" fails with Related Field got invalid lookup: iexact

Why? Because in construct_search (​See Git) it's transformed to pk__iexact__icontains as it found out that the pk is payer_ptr which is FK.

If we want to be correct, it should be "payer_ptr__pk__iexact".

Please let me know if this behaviour is a bug or if is there any reason behind it.

[Mariusz Felisiak]

All cases pk, payer__ptr, and id works with the __exact lookup. Do you need __iexact?

The main difference is that id is AutoField, pk and payer_ptr are recognized as OneToOneField.

[Mariusz Felisiak]

Agreed, this restriction should be documented or fixed.

[Pavel Pančocha]

Replying to Mariusz Felisiak:

All cases pk, payer__ptr, and id works with the __exact lookup. Do you need __iexact?

The main difference is that id is AutoField, pk and payer_ptr are recognized as OneToOneField.

Yes, because the exact fails in the search in the admin. When I try to search something else with chars (eg. test) and I have the lookup for pk__exact if it fails with the exception it cannot convert the test to int. It works for iexact - maybe it is a problem already fixed in newer Django version.

What is the proposed solution here? Should the resulting query be transformed to payer_ptr__pk__iexact?