Many to Many Error

Given these relationships:

# Capability
relationships do
  many_to_many :steps, Hsm.Ash.MCP.Step do
    through Hsm.Ash.MCP.StepCapability
    source_attribute_on_join_resource :capability_id
    destination_attribute_on_join_resource :step_id
  end
end

# Step
relationships do
  many_to_many :capabilities, Hsm.Ash.Workcenters.Capability do
    through Hsm.Ash.MCP.StepCapability
    source_attribute_on_join_resource :step_id
    destination_attribute_on_join_resource :capability_id
  end
end

# StepCapability
relationships do
  belongs_to :capability, Hsm.Ash.Workcenters.Capability,
    allow_nil?: false,
    api: Hsm.Ash.Workcenters
  belongs_to :step, Hsm.Ash.MCP.Step, allow_nil?: false, api: Hsm.Ash.MCP
end

# Capability
relationships do
  many_to_many :steps, Hsm.Ash.MCP.Step do
    through Hsm.Ash.MCP.StepCapability
    source_attribute_on_join_resource :capability_id
    destination_attribute_on_join_resource :step_id
  end
end

# Step
relationships do
  many_to_many :capabilities, Hsm.Ash.Workcenters.Capability do
    through Hsm.Ash.MCP.StepCapability
    source_attribute_on_join_resource :step_id
    destination_attribute_on_join_resource :capability_id
  end
end

# StepCapability
relationships do
  belongs_to :capability, Hsm.Ash.Workcenters.Capability,
    allow_nil?: false,
    api: Hsm.Ash.Workcenters
  belongs_to :step, Hsm.Ash.MCP.Step, allow_nil?: false, api: Hsm.Ash.MCP
end

All of them are in the same API and Registry. I'm getting an error that I don't quite understand (join_relationship_name???):

** (EXIT from #PID<0.96.0>) an exception was raised:
    ** (RuntimeError) Resource `Hsm.Ash.MCP.StepCapability` is not in registry `Hsm.Ash.Workcenters.Registry` for autogenerated join relationship: `:steps_join_assoc`

Relationship was generated by the `many_to_many` relationship `:steps`

If the `through` resource `Hsm.Ash.MCP.StepCapability` is not accepted by the same
api as the destination resource `Hsm.Ash.MCP.Step`,
then you must define that relationship manually. To define it manually, add the following to your
relationships:

    has_many :steps_join_assoc, Hsm.Ash.MCP.StepCapability do
      # configure the relationship attributes
      ...
    end

You can use a name other than `:steps_join_assoc`, but if you do, make sure to
add that to `:steps`, i.e

    many_to_many :steps_join_assoc, Hsm.Ash.MCP.StepCapability do
      ...
      join_relationship_name :your_new_name
    end

        (ash 2.9.5) lib/ash/registry/extensions/resource_validations/verifiers/validate_related_resource_inclusion.ex:43: anonymous fn/5 in Ash.Registry.ResourceValidations.Verifiers.ValidateRelatedResourceInclusion.verify/1
        (elixir 1.14.4) lib/enum.ex:2468: Enum."-reduce/3-lists^foldl/2-0-"/3
        (ash 2.9.5) lib/ash/registry/extensions/resource_validations/verifiers/validate_related_resource_inclusion.ex:16: anonymous fn/4 in Ash.Registry.ResourceValidations.Verifiers.ValidateRelatedResourceInclusion.verify/1
        (elixir 1.14.4) lib/enum.ex:2468: Enum."-reduce/3-lists^foldl/2-0-"/3
        (ash 2.9.5) lib/ash/registry/extensions/resource_validations/verifiers/validate_related_resource_inclusion.ex:15: Ash.Registry.ResourceValidations.Verifiers.ValidateRelatedResourceInclusion.verify/1
        lib/hsm/ash/workcenters/registry.ex:1: anonymous fn/1 in Hsm.Ash.Workcenters.Registry.__verify_ash_dsl__/1
        (elixir 1.14.4) lib/enum.ex:975: Enum."-each/2-lists^foreach/1-0-"/2
        lib/hsm/ash/workcenters/registry.ex:1: Hsm.Ash.Workcenters.Registry.__verify_ash_dsl__/1

** (EXIT from #PID<0.96.0>) an exception was raised:
    ** (RuntimeError) Resource `Hsm.Ash.MCP.StepCapability` is not in registry `Hsm.Ash.Workcenters.Registry` for autogenerated join relationship: `:steps_join_assoc`

Relationship was generated by the `many_to_many` relationship `:steps`

If the `through` resource `Hsm.Ash.MCP.StepCapability` is not accepted by the same
api as the destination resource `Hsm.Ash.MCP.Step`,
then you must define that relationship manually. To define it manually, add the following to your
relationships:

    has_many :steps_join_assoc, Hsm.Ash.MCP.StepCapability do
      # configure the relationship attributes
      ...
    end

You can use a name other than `:steps_join_assoc`, but if you do, make sure to
add that to `:steps`, i.e

    many_to_many :steps_join_assoc, Hsm.Ash.MCP.StepCapability do
      ...
      join_relationship_name :your_new_name
    end

        (ash 2.9.5) lib/ash/registry/extensions/resource_validations/verifiers/validate_related_resource_inclusion.ex:43: anonymous fn/5 in Ash.Registry.ResourceValidations.Verifiers.ValidateRelatedResourceInclusion.verify/1
        (elixir 1.14.4) lib/enum.ex:2468: Enum."-reduce/3-lists^foldl/2-0-"/3
        (ash 2.9.5) lib/ash/registry/extensions/resource_validations/verifiers/validate_related_resource_inclusion.ex:16: anonymous fn/4 in Ash.Registry.ResourceValidations.Verifiers.ValidateRelatedResourceInclusion.verify/1
        (elixir 1.14.4) lib/enum.ex:2468: Enum."-reduce/3-lists^foldl/2-0-"/3
        (ash 2.9.5) lib/ash/registry/extensions/resource_validations/verifiers/validate_related_resource_inclusion.ex:15: Ash.Registry.ResourceValidations.Verifiers.ValidateRelatedResourceInclusion.verify/1
        lib/hsm/ash/workcenters/registry.ex:1: anonymous fn/1 in Hsm.Ash.Workcenters.Registry.__verify_ash_dsl__/1
        (elixir 1.14.4) lib/enum.ex:975: Enum."-each/2-lists^foreach/1-0-"/2
        lib/hsm/ash/workcenters/registry.ex:1: Hsm.Ash.Workcenters.Registry.__verify_ash_dsl__/1

I'm probably missing something obvious, but I can't spot it.

15 Replies

TechnoMage•3y ago

I have not gotten many to many to work quite yet, but mine at lest compile. I suggest looking for references or imports or aliases of Hsm.Ash.MCP.StepCapability given it is in the error and not appearly what you are expecting to be involved.

frankdugan3OP•3y ago

Yeah, pasted the wrong defs. I don't use aliases to avoid those kinds of problems. Post edited w/ correct definitions. ^ Oh, is this as simple as needing to add it to both registries? :thinkies:

TechnoMage•3y ago

It is making up the resource name 'steps_join_assoc' for some reason. It looks like you have through specified, I would double check that the join resource is in the same API and registry as the others.

frankdugan3OP•3y ago

The join resource is in the MCP registry/api, not Workcenters. I'm just not clear on how to deal with that, as specifying the api on either/both many_to_many still produces the same error. It's also not clear in the docs if the api option in a many_to_many is supposed to point to the API of t he destination resource or the join resource.

TechnoMage•3y ago

The docs state that the API option is for the destination resource. Looks like it is a missing option. I would file an issue, and in the mean time add the join resource to both API and Registries.

frankdugan3OP•3y ago

The docs say "related entity" for the api on a many_to_many, which to me is not clearly indicating "destination", which is the term it consistently uses. I mean, that's probably what it means, but it's unclear IMO. Yeah, I'm consistently doing something wrong w/ my cross-api many-to-many relationships because they all have this problem. @Zach Daniel When you get a chance, could use some guidance. (no rush) 😵‍💫 OK, I think the solution was a few steps: 1) add the api options to all the many-to-many relationships, 2) add the join resource to both api/registries and 3) make sure the join resource specifies the API for each relationship. Need to do this to the rest of them to make sure.

ZachDaniel•3y ago

You shouldn’t need to add the join resource to both apis *registries The idea of the warning is that if you set the api of a many to many relationship, and we generate a has_many for it, we assume that the through resource is in the destination api. If it’s not, then you need to define the underlying has_many yourself and not set an api (or set it to the correct api) And then use that with join_relationship And the api in a many to many should point to the destination resource api.

frankdugan3OP•3y ago

Might be a bug then, because given this:

# Step (MCP API)
many_to_many :capabilities, Hsm.Ash.Workcenters.Capability do
  through Hsm.Ash.MCP.StepCapability
  source_attribute_on_join_resource :step_id
  destination_attribute_on_join_resource :capability_id
  api Hsm.Ash.Workcenters
end

# Capability (Workcenters API)
many_to_many :mcp_steps, Hsm.Ash.MCP.Step do
  through Hsm.Ash.MCP.StepCapability
  source_attribute_on_join_resource :capability_id
  destination_attribute_on_join_resource :step_id
  api Hsm.Ash.MCP
end

# StepCapability (MCP API)
relationships do
  belongs_to :capability, Hsm.Ash.Workcenters.Capability,
    allow_nil?: false,
    api: Hsm.Ash.Workcenters

  belongs_to :step, Hsm.Ash.MCP.Step, allow_nil?: false, api: Hsm.Ash.MCP
end

# Step (MCP API)
many_to_many :capabilities, Hsm.Ash.Workcenters.Capability do
  through Hsm.Ash.MCP.StepCapability
  source_attribute_on_join_resource :step_id
  destination_attribute_on_join_resource :capability_id
  api Hsm.Ash.Workcenters
end

# Capability (Workcenters API)
many_to_many :mcp_steps, Hsm.Ash.MCP.Step do
  through Hsm.Ash.MCP.StepCapability
  source_attribute_on_join_resource :capability_id
  destination_attribute_on_join_resource :step_id
  api Hsm.Ash.MCP
end

# StepCapability (MCP API)
relationships do
  belongs_to :capability, Hsm.Ash.Workcenters.Capability,
    allow_nil?: false,
    api: Hsm.Ash.Workcenters

  belongs_to :step, Hsm.Ash.MCP.Step, allow_nil?: false, api: Hsm.Ash.MCP
end

Hsm.Ash.MCP.StepCapability is added to the MCP registry, but will still give the compile error unless I also add it to the Workcenters registry. :thinkies:

ZachDaniel•3y ago

Well, the through resource is only in one of them So you will always get an error unless you manually define the underlying has_many relationship for one of them not specifying the api for that one (I.e the through resource is in my api not theirs) If you define two many to many relationships across an api boundary without doing that, one of them will always error unless the through resource is in both.

frankdugan3OP•3y ago

Ahh... OK. Is there any harm to just including the through relationship in both registries to avoid the manual has_many? Just trying to figure out best practice, will PR some of these details in the guides/docs.

ZachDaniel•3y ago

No harm really, no. But I’d suggest just picking which api it belongs in and on one end define the has_many for the many_to_many

rohan•2y ago

came up against this now, it doesn't seem to be documented in the relationship docs anywhere actually I'm really confused by what I'm supposed to do here. I'm getting:

an exception was raised:
    ** (RuntimeError) Resource `Scribble.Scribe.UserMedicalTerm` is not accepted by api `Scribble.EmailHandler` for autogenerated join relationship: `:users_join_assoc`

Relationship was generated by the `many_to_many` relationship `:users`

If the `through` resource `Scribble.Scribe.UserMedicalTerm` is not accepted by the same
api as the destination resource `Scribble.EmailHandler.User`,
then you must define that relationship manually. To define it manually, add the following to your
relationships:

    has_many :users_join_assoc, Scribble.Scribe.UserMedicalTerm do
      # configure the relationship attributes
      ...
    end

You can use a name other than `:users_join_assoc`, but if you do, make sure to
add that to `:users`, i.e

    many_to_many :users_join_assoc, Scribble.Scribe.UserMedicalTerm do
      ...
      join_relationship_name :your_new_name
    end

an exception was raised:
    ** (RuntimeError) Resource `Scribble.Scribe.UserMedicalTerm` is not accepted by api `Scribble.EmailHandler` for autogenerated join relationship: `:users_join_assoc`

Relationship was generated by the `many_to_many` relationship `:users`

If the `through` resource `Scribble.Scribe.UserMedicalTerm` is not accepted by the same
api as the destination resource `Scribble.EmailHandler.User`,
then you must define that relationship manually. To define it manually, add the following to your
relationships:

    has_many :users_join_assoc, Scribble.Scribe.UserMedicalTerm do
      # configure the relationship attributes
      ...
    end

You can use a name other than `:users_join_assoc`, but if you do, make sure to
add that to `:users`, i.e

    many_to_many :users_join_assoc, Scribble.Scribe.UserMedicalTerm do
      ...
      join_relationship_name :your_new_name
    end

am I supposed to literally call it :users_join_assoc? I think having an example of this in the docs would be really helpful, right now the docs only says that the api must be defined if many_to_many is crossing api boundaries

ZachDaniel•2y ago

You can call it whatever you want, but then you need to say join_relationship :relationship_name in your many to many. Agreed an example would be helpful

drumusician•2y ago

I have a question related to the many_to_many. I have a pretty basic many to many in one Api. Currently I'm seeding some data, but it fails to write the join table when I add the associated data directly in the params. Is this not supported (yet)? In Ecto this would mean adding the cast_assoc for the related items checking out the managing relationships guide as it seems that's where I can configure this

ZachDaniel•2y ago

Yep 🙂 managing relationships (or custom changes w/ after action hooks) is what you'd want there

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