How to write relationships with no_attributes?

rapidfsub · October 27, 2024, 5:55am

This is Product.relationships code.

rapidfsub/sonet/blob/develop/test/support/lib/sonet_lib/seven_eleven/product.ex#L44


      
          end
          
          attributes do
            uuid_v7_primary_key :id
            attribute :is_adult_only, :boolean, allow_nil?: false, public?: true
          end
          
          relationships do
            has_many :inventories, SevenEleven.Inventory, destination_attribute: :product_id
          
            has_many :stores, SevenEleven.Store do
              no_attributes? true
              filter expr(inventories.product_id == parent(id))
            end
          
            has_many :stores_alt1, SevenEleven.Store do
              no_attributes? true
              filter expr(inventories.store_id == parent(inventories.store_id))
            end
          
            has_many :stores_alt2, SevenEleven.Store do

This is load test code for above relationships.

github.com

rapidfsub/sonet/blob/develop/test/sonet_lib/seven_eleven/product_test.exs#L24


      
              store
            end
          
            for _ <- 1..3 do
              SevenEleven.store_fixture()
            end
          
            %{product: product}
          end
          
          test "stores", ~M{product} do
            assert %{stores: [_, _, _]} = Ashex.load!(product, [:stores])
          
            assert_raise Ecto.Query.CompileError, fn ->
              Ashex.load!(product, [:stores_alt1])
            end
          
            assert_raise Ecto.Query.CompileError, fn ->
              Ashex.load!(product, [:stores_alt2])
            end
          end

I think three stores, stores_alt1, stores_alt2 relationships should be equivalent.
But, only the stores relationship works,
and other two relationships raise Ecto.Query.CompileError.

I’m confused how to write relationship with no_attributes? true.
Is there any proper way to write this kind of relationships correctly? @zachdaniel

zachdaniel · October 27, 2024, 8:42pm

What are the details of the error? Just knowing Ecto.Query.CompileError is not really useful without more information.

With that said, could you also describe specifically what the stores relationship is meant to provide?

I can’t really give advice as I don’t know what you’re specifically looking to do.

rapidfsub · October 27, 2024, 11:35pm

Here are the stacktraces.

stacktrace for stores_alt1

  1) test relationships stores (SonetLib.SevenEleven.ProductTest)
     test/sonet_lib/seven_eleven/product_test.exs:24
     ** (Ecto.Query.CompileError) only one distinct expression is allowed in query
     code: Ashex.load!(product, [:stores_alt1])
     stacktrace:
       (ash_postgres 2.4.11) lib/data_layer.ex:1102: AshPostgres.DataLayer.lateral_join_query/3
       (ash_postgres 2.4.11) lib/data_layer.ex:961: AshPostgres.DataLayer.run_query_with_lateral_join/4
       (ash 3.4.35) lib/ash/actions/read/read.ex:2650: Ash.Actions.Read.run_query/4
       (ash 3.4.35) lib/ash/actions/read/read.ex:542: anonymous fn/8 in Ash.Actions.Read.do_read/5
       (ash 3.4.35) lib/ash/actions/read/read.ex:886: Ash.Actions.Read.maybe_in_transaction/3
       (ash 3.4.35) lib/ash/actions/read/read.ex:269: Ash.Actions.Read.do_run/3
       (ash 3.4.35) lib/ash/actions/read/read.ex:81: anonymous fn/3 in Ash.Actions.Read.run/3
       (ash 3.4.35) lib/ash/actions/read/read.ex:80: Ash.Actions.Read.run/3
       (ash 3.4.35) lib/ash/actions/read/relationships.ex:413: anonymous fn/2 in Ash.Actions.Read.Relationships.do_fetch_related_records/4
       (ash 3.4.35) lib/ash/actions/read/relationships.ex:65: Ash.Actions.Read.Relationships.fetch_related_records/4
       (ash 3.4.35) lib/ash/actions/read/relationships.ex:24: Ash.Actions.Read.Relationships.load/4
       (ash 3.4.35) lib/ash/actions/read/read.ex:298: Ash.Actions.Read.do_run/3
       (ash 3.4.35) lib/ash/actions/read/read.ex:81: anonymous fn/3 in Ash.Actions.Read.run/3
       (ash 3.4.35) lib/ash.ex:1859: Ash.load/3
       (ash 3.4.35) lib/ash.ex:1813: Ash.load/3
       (ash 3.4.35) lib/ash.ex:1754: Ash.load!/3
       test/sonet_lib/seven_eleven/product_test.exs:28: (test)

stacktrace for stores_alt2

  1) test relationships stores (SonetLib.SevenEleven.ProductTest)
     test/sonet_lib/seven_eleven/product_test.exs:24
     ** (Ecto.Query.CompileError) only one distinct expression is allowed in query
     code: Ashex.load!(product, [:stores_alt2])
     stacktrace:
       (ash_postgres 2.4.11) lib/data_layer.ex:1102: AshPostgres.DataLayer.lateral_join_query/3
       (ash_postgres 2.4.11) lib/data_layer.ex:961: AshPostgres.DataLayer.run_query_with_lateral_join/4
       (ash 3.4.35) lib/ash/actions/read/read.ex:2650: Ash.Actions.Read.run_query/4
       (ash 3.4.35) lib/ash/actions/read/read.ex:542: anonymous fn/8 in Ash.Actions.Read.do_read/5
       (ash 3.4.35) lib/ash/actions/read/read.ex:886: Ash.Actions.Read.maybe_in_transaction/3
       (ash 3.4.35) lib/ash/actions/read/read.ex:269: Ash.Actions.Read.do_run/3
       (ash 3.4.35) lib/ash/actions/read/read.ex:81: anonymous fn/3 in Ash.Actions.Read.run/3
       (ash 3.4.35) lib/ash/actions/read/read.ex:80: Ash.Actions.Read.run/3
       (ash 3.4.35) lib/ash/actions/read/relationships.ex:413: anonymous fn/2 in Ash.Actions.Read.Relationships.do_fetch_related_records/4
       (ash 3.4.35) lib/ash/actions/read/relationships.ex:65: Ash.Actions.Read.Relationships.fetch_related_records/4
       (ash 3.4.35) lib/ash/actions/read/relationships.ex:24: Ash.Actions.Read.Relationships.load/4
       (ash 3.4.35) lib/ash/actions/read/read.ex:298: Ash.Actions.Read.do_run/3
       (ash 3.4.35) lib/ash/actions/read/read.ex:81: anonymous fn/3 in Ash.Actions.Read.run/3
       (ash 3.4.35) lib/ash.ex:1859: Ash.load/3
       (ash 3.4.35) lib/ash.ex:1813: Ash.load/3
       (ash 3.4.35) lib/ash.ex:1754: Ash.load!/3
       test/sonet_lib/seven_eleven/product_test.exs:32: (test)

rapidfsub · October 27, 2024, 11:43pm

I will explain more about my question.

There are three resources: Store, Inventory, Product.
Store and Product is simple resource, and Inventory is join table resource.

Store
has_many :inventories
Product
has_many :inventories
Inventory
belongs_to :store
belongs_to :product

I know there is many_to_many feature,
but I wanted to show you there are some hard things when using no_attributes? true.

A private project in our company uses no_attributes? true a lot
(There are some scenarios our company have, only no_attributes? true can be a solution.),
and I meet this kind of error a lot.
How can I avoid these errors and write correct relationship?
Or is this an bug?

zachdaniel · October 27, 2024, 11:52pm

** (Ecto.Query.CompileError) only one distinct expression is allowed in query
is a bug.

Please open a bug report.

zachdaniel · October 27, 2024, 11:53pm

If you can, please provide a reproduction and as much detail as you can. Ideally a test I can run that reproduces the specific error

rapidfsub · October 28, 2024, 12:33am

I opened a bug report about this.

github.com/ash-project/ash_postgres

Ecto.Query.CompileError when using no_attributes? true in relationships

opened 12:27AM - 28 Oct 24 UTC

rapidfsub

bug needs review

**Describe the bug** When using `no_attributes? true` in relationships, I encou…nter `Ecto.Query.CompileError` frequently. There are three resources. - Store has_many :inventories - Product has_many :inventories - Inventory (join table resource) belongs_to :store belongs_to :product - relationship code in Product ``` defmodule SonetLib.SevenEleven.Product do relationships do has_many :stores, SevenEleven.Store do no_attributes? true filter expr(inventories.product_id == parent(id)) end has_many :stores_alt1, SevenEleven.Store do no_attributes? true filter expr(inventories.store_id == parent(inventories.store_id)) end has_many :stores_alt2, SevenEleven.Store do no_attributes? true filter expr(id == parent(inventories.store_id)) end end end ``` I think these three relationships are equivalent, but only the first one works. And the other two relationships raise error when loading them. - stacktrace ``` 1) test relationships stores (SonetLib.SevenEleven.ProductTest) test/sonet_lib/seven_eleven/product_test.exs:24 ** (Ecto.Query.CompileError) only one distinct expression is allowed in query code: Ashex.load!(product, [:stores_alt1]) stacktrace: (ash_postgres 2.4.11) lib/data_layer.ex:1102: AshPostgres.DataLayer.lateral_join_query/3 (ash_postgres 2.4.11) lib/data_layer.ex:961: AshPostgres.DataLayer.run_query_with_lateral_join/4 (ash 3.4.35) lib/ash/actions/read/read.ex:2650: Ash.Actions.Read.run_query/4 (ash 3.4.35) lib/ash/actions/read/read.ex:542: anonymous fn/8 in Ash.Actions.Read.do_read/5 (ash 3.4.35) lib/ash/actions/read/read.ex:886: Ash.Actions.Read.maybe_in_transaction/3 (ash 3.4.35) lib/ash/actions/read/read.ex:269: Ash.Actions.Read.do_run/3 (ash 3.4.35) lib/ash/actions/read/read.ex:81: anonymous fn/3 in Ash.Actions.Read.run/3 (ash 3.4.35) lib/ash/actions/read/read.ex:80: Ash.Actions.Read.run/3 (ash 3.4.35) lib/ash/actions/read/relationships.ex:413: anonymous fn/2 in Ash.Actions.Read.Relationships.do_fetch_related_records/4 (ash 3.4.35) lib/ash/actions/read/relationships.ex:65: Ash.Actions.Read.Relationships.fetch_related_records/4 (ash 3.4.35) lib/ash/actions/read/relationships.ex:24: Ash.Actions.Read.Relationships.load/4 (ash 3.4.35) lib/ash/actions/read/read.ex:298: Ash.Actions.Read.do_run/3 (ash 3.4.35) lib/ash/actions/read/read.ex:81: anonymous fn/3 in Ash.Actions.Read.run/3 (ash 3.4.35) lib/ash.ex:1859: Ash.load/3 (ash 3.4.35) lib/ash.ex:1813: Ash.load/3 (ash 3.4.35) lib/ash.ex:1754: Ash.load!/3 test/sonet_lib/seven_eleven/product_test.exs:28: (test) ``` **To Reproduce** I will attach some links to my public repo. You can reproduce it easily with test code. 1. resource `Store` https://github.com/rapidfsub/sonet/blob/develop/test/support/lib/sonet_lib/seven_eleven/store.ex 2. resource `Product` https://github.com/rapidfsub/sonet/blob/develop/test/support/lib/sonet_lib/seven_eleven/product.ex 3. resource `Inventory` (join table resource for `Store` and `Product`) https://github.com/rapidfsub/sonet/blob/develop/test/support/lib/sonet_lib/seven_eleven/inventory.ex 4. test code for reproduction https://github.com/rapidfsub/sonet/blob/develop/test/sonet_lib/seven_eleven/product_test.exs#L24 I know I can use `many_to_many` feature in this example, but I need a simple example to show the bug in `no_attributes? true` feature. **Expected behavior** - relationships works without any error **Runtime** - Elixir version 1.17.0-otp-27 - Erlang version 27.0 - OS mac os sequoia - Ash version 3.4.35 - any related extension versions ash_postgres 2.4.11 **Additional context** I wrote a question about this in elixir forum below. https://elixirforum.com/t/how-to-write-relationships-with-no-attributes/67042

zachdaniel · October 28, 2024, 2:33am

Thank you, I’ll take a look in the next day or two.

zachdaniel · October 28, 2024, 4:04pm

This is fixed in main of ash_postgres. I will release new versions of ash and ash_postgres this week.

rapidfsub · October 28, 2024, 10:46pm

Thanks.

rapidfsub · October 28, 2024, 11:39pm

The bug I reported is fixed, but I found another one related to original one.
I opened a new issue in ash_postgres.

github.com/ash-project/ash_postgres

RuntimeError when using no_attributes? true relationships in filter expr

opened 11:38PM - 28 Oct 24 UTC

rapidfsub

bug needs review

**Describe the bug** This issue is fixed. https://github.com/ash-project/ash_p…ostgres/issues/412 But still a bug is remaining. When I use the relationship in filter expr, a RuntimeError occurs. The three read actions below should be equivalent, I think. But, only `list_by_store_id` works, and `list_by_store_id_alt1`, `list_by_store_id_alt2` don't work and raise error. - actions in resource ``` defmodule SonetLib.SevenEleven.Product do actions do defaults [:read, create: :*] read :list_by_store_id do argument :store_id, :string, allow_nil?: false filter expr(stores.id == ^arg(:store_id)) end read :list_by_store_id_alt1 do argument :store_id, :string, allow_nil?: false filter expr(stores_alt1.id == ^arg(:store_id)) end read :list_by_store_id_alt2 do argument :store_id, :string, allow_nil?: false filter expr(stores_alt2.id == ^arg(:store_id)) end update :purchase end end ``` - stacktrace ``` 1) test relationships stores (SonetLib.SevenEleven.ProductTest) test/sonet_lib/seven_eleven/product_test.exs:25 ** (RuntimeError) Error while building reference: inventories.store_id stacktrace: (ash_sql 0.2.37) lib/expr.ex:1796: AshSql.Expr.default_dynamic_expr/6 (ash_sql 0.2.37) lib/expr.ex:909: AshSql.Expr.default_dynamic_expr/6 (ash_sql 0.2.37) lib/filter.ex:37: anonymous fn/2 in AshSql.Filter.add_filter_expression/2 (elixir 1.17.0) lib/enum.ex:2531: Enum."-reduce/3-lists^foldl/2-0-"/3 (ash_postgres 2.4.11) lib/data_layer.ex:2998: AshPostgres.DataLayer.filter/4 (ash 3.4.36) lib/ash/query/query.ex:3106: Ash.Query.maybe_filter/3 (ash 3.4.36) lib/ash/query/query.ex:2977: Ash.Query.data_layer_query/2 (ash_sql 0.2.37) lib/join.ex:439: AshSql.Join.related_query/3 (ash_sql 0.2.37) lib/join.ex:345: AshSql.Join.related_subquery/3 (ash_sql 0.2.37) lib/join.ex:873: AshSql.Join.join_relationship/8 (ash_sql 0.2.37) lib/join.ex:136: anonymous fn/10 in AshSql.Join.join_all_relationships/10 (elixir 1.17.0) lib/enum.ex:4858: Enumerable.List.reduce/3 (elixir 1.17.0) lib/enum.ex:2585: Enum.reduce_while/3 (ash_postgres 2.4.11) lib/data_layer.ex:2991: AshPostgres.DataLayer.filter/4 (ash 3.4.36) lib/ash/query/query.ex:3106: Ash.Query.maybe_filter/3 (ash 3.4.36) lib/ash/query/query.ex:2977: Ash.Query.data_layer_query/2 (ash 3.4.36) lib/ash/actions/read/read.ex:544: anonymous fn/8 in Ash.Actions.Read.do_read/5 (ash 3.4.36) lib/ash/actions/read/read.ex:890: Ash.Actions.Read.maybe_in_transaction/3 (ash 3.4.36) lib/ash/actions/read/read.ex:273: Ash.Actions.Read.do_run/3 (ash 3.4.36) lib/ash/actions/read/read.ex:81: anonymous fn/3 in Ash.Actions.Read.run/3 ``` **To Reproduce** This is the test code to reproduce in my public repo. https://github.com/rapidfsub/sonet/blob/develop/test/sonet_lib/seven_eleven/product_test.exs#L25 **Expected behavior** No error raises, when using relationship in expr. ** Runtime - Elixir version 1.17.0-otp-27 - Erlang version 27.0 - OS mac os sequoia - Ash version git ref ee9415e7bff74210c1e4c3395dc619318a8eee47 - any related extension versions ash_postgres git ref 0e336d56e1091beec15d6f9173f5067e0a0f9271 **Additional context** Add any other context about the problem here.