Ensure inherited nested exposures are merged

[pirhoo]

Hello,

This PR want to fix a limitation of this gem with nested expose on child entities.

Problem

I noticed that when an entity inherits from another, nested exposures are not merged (as opposed to Grape Entity) in the definition object. For instance this won't work:

class Nested < Grape::Entity
  expose :nested, documentation: { type: Hash, desc: 'Nested entity' } do
    expose :some1, documentation: { type: 'String', desc: 'Nested some 1' }
    expose :some2, documentation: { type: 'String', desc: 'Nested some 2' }
  end
end

class NestedChild < Nested
  expose :nested, documentation: { type: Hash, desc: 'Nested entity' } do
    expose :some3, documentation: { type: 'String', desc: 'Nested some 3' }
  end
end

Would produce this definition:

{
  "definitions": {
    "Nested": {
      "type": "object",
      "properties": {
        "nested": {
          "type": "object",
          "properties": {
            "some1": {
              "type": "string",
              "description": "Nested some 1"
            },
            "some2": {
              "type": "string",
              "description": "Nested some 2"
            }
          },
          "description": "Nested entity"
        }
      }
    },
    "NestedChild": {
      "type": "object",
      "properties": {
        "nested": {
          "type": "object",
          "properties": {
            "some1": {
              "type": "string",
              "description": "Nested some 1"
            },
            "some2": {
              "type": "string",
              "description": "Nested some 2"
            }
          },
          "description": "Nested entity"
        }
      }
    }
  }
}

Solution

Instead of listing params from the first match of a given property (with find_by) we use all exposed properties on the current model (with select_by). This allows to get exposed properties both from Nested and NestedChild.

With those changes, the new property "some3" is now visible in the definition:

{
  "definitions": {
    "Nested": {
      "type": "object",
      "properties": {
        "nested": {
          "type": "object",
          "properties": {
            "some1": {
              "type": "string",
              "description": "Nested some 1"
            },
            "some2": {
              "type": "string",
              "description": "Nested some 2"
            }
          },
          "description": "Nested entity"
        }
      }
    },
    "NestedChild": {
      "type": "object",
      "properties": {
        "nested": {
          "type": "object",
          "properties": {
            "some1": {
              "type": "string",
              "description": "Nested some 1"
            },
            "some2": {
              "type": "string",
              "description": "Nested some 2"
            },
            "some3": {
              "type": "string",
              "description": "Nested some 3"
            }
          },
          "description": "Nested entity"
        }
      }
    }
  }
}

Thanks!

[dblock]

Thanks! Add a line to CHANGELOG and we're good to go.

[pirhoo]

Done ;) Thanks!

[dblock]

@pirhoo you'll have to fix that changelog line :) sorry

[pirhoo]

Oups, sorry!