Ash Elixir•3w ago

Correct Way to Display Spark.Error.DslError?

Hi! I’m writing a custom DSL extension and I’m struggling with making Spark.Error.DslError show up in the right place. I followed patterns from core Ash code (like default_accept.ex and verify_identities.ex), and also looked at extensions like Ash Cloak. Here's what I did in my verifier:

  @impl true
  def verify(dsl_state) do
    inferred_attrs = InferredAttributes.Info.inferred_attributes(dsl_state)

    for attr <- inferred_attrs do
      if !Ash.Resource.Info.attribute(dsl_state, attr.name) do
        raise Spark.Error.DslError,
          module: Spark.Dsl.Verifier.get_persisted(dsl_state, :module),
          message: "All inferred attributes must be attributes. Got: #{inspect(attr.name)}",
          path: [:inferred_attributes, attr.name]
      end
    end

    :ok
  end

  @impl true
  def verify(dsl_state) do
    inferred_attrs = InferredAttributes.Info.inferred_attributes(dsl_state)

    for attr <- inferred_attrs do
      if !Ash.Resource.Info.attribute(dsl_state, attr.name) do
        raise Spark.Error.DslError,
          module: Spark.Dsl.Verifier.get_persisted(dsl_state, :module),
          message: "All inferred attributes must be attributes. Got: #{inspect(attr.name)}",
          path: [:inferred_attributes, attr.name]
      end
    end

    :ok
  end

This seems not to raise, so I tried again this time in the transformer code:

  @impl true
  def transform(dsl_state) do
    module = Spark.Dsl.Transformer.get_persisted(dsl_state, :module)
    inferred_attrs = InferredAttributes.Info.inferred_attributes(dsl_state)

    Enum.reduce_while(inferred_attrs, {:ok, dsl_state}, fn attr, {:ok, dsl_state} ->
      attribute = Ash.Resource.Info.attribute(dsl_state, attr.name)

      if !attribute do
        raise Spark.Error.DslError,
          module: module,
          message: "No attribute called #{attr.name} found",
          path: [:inferred_attributes, attr.name]
      end

      if attribute.primary_key? do
        raise Spark.Error.DslError,
          module: module,
          message: "Cannot infer primary key attribute",
          path: [:inferred_attributes, attr.name]
      end

      {:cont, {:ok, dsl_state}}
    end)
  end

  @impl true
  def transform(dsl_state) do
    module = Spark.Dsl.Transformer.get_persisted(dsl_state, :module)
    inferred_attrs = InferredAttributes.Info.inferred_attributes(dsl_state)

    Enum.reduce_while(inferred_attrs, {:ok, dsl_state}, fn attr, {:ok, dsl_state} ->
      attribute = Ash.Resource.Info.attribute(dsl_state, attr.name)

      if !attribute do
        raise Spark.Error.DslError,
          module: module,
          message: "No attribute called #{attr.name} found",
          path: [:inferred_attributes, attr.name]
      end

      if attribute.primary_key? do
        raise Spark.Error.DslError,
          module: module,
          message: "Cannot infer primary key attribute",
          path: [:inferred_attributes, attr.name]
      end

      {:cont, {:ok, dsl_state}}
    end)
  end

This raises as expected, but the error isn't tied to the DSL location. It does show up, but only on line 1 of the module. Is there a recommended way to raise Spark.Error.DslError so that it points you to the invalid DSL section or field? Any help or examples appreciated! 🙏

3 Replies

ZachDaniel•3w ago

Currently spark DSL errors cannot point at source locations. It's a feature I'd like to support.

adonigOP•3w ago

How does Ash do the context errors? Is it validation on the Spark.Dsl.Entity? 🤔

adonigOP•3w ago

Just realized Ash Cloak doesn't modify the default actions. Is that intentional? my bad, forgot def after?(Ash.Resource.Transformers.DefaultAccept), do: true

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Correct Way to Display Spark.Error.DslError?

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