External references' references are not imported via import-mapping configuration

[wafer-bw]

When an external reference imported via import-mapping such as the following has references (a chain of references), they are not resolved/imported and the generated code does not compile.

api/oapi.cfg.yml

# ...
import-mapping:
  ../item/openapi.yml: github.com/deepmap/oapi-codegen/internal/test/issues/issue-1223/item
output: api.gen.go
# ...

api/openapi.yml

# ...
paths:
  /item/{itemid}:
    $ref: '../item/openapi.yml#/components/pathItems/ItemPath'
# ...

item/openapi.yml

# ...
  pathItems:
    ItemPath:
      get:
        summary: Get an item
        operationId: getItem
        parameters:
          - $ref: '#/components/parameters/ItemID'
        responses:
          '200':
            description: success
            content:
              application/json:
                schema:
                  $ref: '#/components/schemas/Item'
# ...

git clone https://github.com/wafer-bw/oapi-codegen
cd oapi-codegen/internal/test
go generate ./issues/issue-1223/...
go test ./issues/issue-1223/...
# # github.com/deepmap/oapi-codegen/internal/test/issues/issue-1223/api
# issues/issue-1223/api/api.gen.go:21:35: undefined: ItemID
# issues/issue-1223/api/api.gen.go:33:13: undefined: ItemID
# issues/issue-1223/api/api.gen.go:78:9: undefined: ItemID
# issues/issue-1223/api/api.gen.go:85:29: undefined: Item
# issues/issue-1223/api/api.gen.go:114:59: undefined: ItemID
# FAIL    github.com/deepmap/oapi-codegen/internal/test/issues/issue-1223 [build failed]
# ?       github.com/deepmap/oapi-codegen/internal/test/issues/issue-1223/item    [no test files]
# FAIL

• Diff/PR: https://github.com/wafer-bw/oapi-codegen/pull/1
• Commit: https://github.com/deepmap/oapi-codegen/commit/943aa4f27cf35a8aadda637fe23a4b71d2a09262
• Issue Folder