Improve error message for generic actions used in

[dallingson]

Improve error message for generic actions used in GraphQL mutation blocks

Problem

When developers accidentally use a generic action (type :action) in a typed GraphQL mutation block (create, update, or destroy), they get a cryptic KeyError instead of a helpful error message.

Before:

** (KeyError) key :error_location not found in: %AshGraphql.Resource.Mutation{...}

Solution

Added early validation that catches the mistake and provides a clear error message with fix suggestions.

After:

** (RuntimeError) Invalid GraphQL mutation.

`create` references Ash action `:some_generic_action`, but that action has type `:action`.

GraphQL `create` mutations require an Ash action with type `:create`.

Resource: Safari.Outcrop.SupplementalDocument

Fix:
  • Define an Ash `:create` action
  • Or expose the generic action under `graphql.actions`

Changes

• Added validation in mutation_types/4 to catch generic actions in typed mutation blocks early
• Changed unsafe field access to Map.get/3 for defensive coding
• Added tests covering all mutation types (create, update, destroy)

Contributor checklist

• I accept the AI Policy, or AI was not used in the creation of this PR.
• Bug fixes include regression tests
• Chores
• Documentation changes
• Features include unit/acceptance tests
• Refactoring
• Update dependencies

[zachdaniel]

Looks like some conflicts. I also know there is a failing build step, I'll address that separately. Please just confirm your tests pass locally and we can merge once the other checks pass 😄

[dallingson]

@zachdaniel Yes, my tests do pass locally! :) If you notice anything else, just let me know.