Spark does not escape nested function types

[briankariuki]

Describe the bug
I have an entity defined with a schema option (i.e news) that is a keyword list with its key types defined by keys. One of the fields (publication_date) may be a function that will return a string for the field. But when I compile this code, I get an error

Error: cannot inject attribute @urls into function/macro because cannot escape #Function<>

It does compile when I remove {:fun, [:map], :string} from the list of type options for publication_date. It does escape the function correctly for the :path option

@urls %Spark.Dsl.Entity{
    name: :url,
    target: AshSitemap.Url,
    examples: [
      "url 'index.html', priority: 0.5"
    ],
    schema: [
      path: [
        type: {
          :or,
          [:string, {:fun, [:map], :string}]
        },
        required: true
      ],
      priority: [type: :float, required: false],
      news: [
        type: :non_empty_keyword_list,
        keys: [
          publication: [
            type: :string,
            required: true
          ],
          publication_date: [
            type: {
              :or,
              [:string, :atom, {:fun, [:map], :string}]
            },
            required: true
          ],
          title: [
            type: {
              :or,
              [:string, :atom]
            },
            required: true
          ],
          keywords: [
            type: {:list, :string},
            required: true
          ]
        ],
        required: false
      ]
    ],
    args: [:path]
  }

To Reproduce
Use the above urls entity as an example

Expected behavior
I expected spark to parse the types of the publication_date correctly

Runtime

• Elixir version 1.17
• Erlang version 26.2.5
• OS MacOS 14.3.1
• Spark version 2.2.10
• any related extension versions

[zachdaniel]

So spark can't choose to escape/not escape types (that happens after spark comes into play), but what we should do given how these specifications are generally used is not have any three-tuple types.

[zachdaniel]

The function type needs some overhauling anyway, as we need to be able to name each argument type. For now, the type just won't be usable in that context.

[briankariuki]

So spark can't choose to escape/not escape types (that happens after spark comes into play), but what we should do given how these specifications are generally used is not have any three-tuple types.

Thanks for the explanation. So this means its impossible to allow a function to customize the :publication_date?

[zachdaniel]

You would just need to either use a custom type or a less specific function type, i.e {:fun, 1} means "any one argument function", and that can be successfully unquoted.