[sdkgen/go] Array<Map<Map<Object>>> generates undefined nested input helper types

Author: corymhallCreated Jul 24, 2026Updated Sep 17, 2026

Labelskind/buglanguage/goarea/codegenpulumi/pulumi

What happened?

Generating a Go SDK for a schema containing Array<Map<Map<Object>>>, where the leaf is a named object type, succeeds but produces Go code that does not compile.

The resource input references:

ScalingResourceMapMapArrayInput

but codegen instead emits a mismatched type named:

ScalingResourceArgsMapMapArrayInput

That generated type also references undefined ScalingResourceArgsMapMapInput and ScalingResourceArgsMapMapOutput types.

I expected Go SDK generation either to produce a consistent set of nested collection helper types or return a schema validation error. It should not report successful generation and then produce an uncompilable SDK.

Example

Save this as schema.json:

json

{
  "name": "repro",
  "version": "0.1.0",
  "resources": {
    "repro:index:Foo": {
      "inputProperties": {
        "scalingResources": {
          "type": "array",
          "items": {
            "type": "object",
            "additionalProperties": {
              "type": "object",
              "additionalProperties": {
                "$ref": "#/types/repro:index:ScalingResource"
              }
            }
          }
        }
      },
      "properties": {
        "scalingResources": {
          "type": "array",
          "items": {
            "type": "object",
            "additionalProperties": {
              "type": "object",
              "additionalProperties": {
                "$ref": "#/types/repro:index:ScalingResource"
              }
            }
          }
        }
      }
    }
  },
  "types": {
    "repro:index:ScalingResource": {
      "type": "object",
      "properties": {
        "name": {
          "type": "string"
        }
      },
      "required": ["name"]
    }
  },
  "language": {
    "go": {
      "importBasePath": "example.com/repro/sdk/go/repro"
    }
  }
}

Generate and compile the SDK:

bash

mkdir sdk

pulumi package gen-sdk schema.json \
  --language go \
  --out sdk \
  --version 0.1.0

cd sdk/go
go mod init example.com/repro/sdk/go
go mod edit -require=github.com/pulumi/pulumi/sdk/[email protected]
go mod tidy
go build ./...

The build fails with:

# example.com/repro/sdk/go/repro
repro/foo.go:65:19: undefined: ScalingResourceMapMapArrayInput
repro/pulumiTypes.go:110:39: undefined: ScalingResourceArgsMapMapInput
repro/pulumiTypes.go:149:72: undefined: ScalingResourceArgsMapMapOutput
repro/pulumiTypes.go:152:6: undefined: ScalingResourceArgsMapMapOutput

Output of `pulumi about`

This reproducer generates an SDK directly rather than running a Pulumi project, so pulumi about is not applicable.

Pulumi CLI: v3.253.0
Go: go1.25.11 darwin/arm64
OS: Darwin arm64

Additional context

This was encountered in pulumi-aws-native for the ARC Region Switch PlanEksResourceScalingConfiguration.scalingResources property. AWS Native currently has to represent this collection as Any to keep its generated Go SDK compilable.

Nested primitive collections now compile, including three-level primitive combinations added by #21248. The remaining failure appears specific to nested collections whose leaf is a named object type.

This resembles the invalid Args collection helper names previously reported in #7595 and fixed by #7779, but the Array<Map<Map<Object>>> shape still triggers the mismatch in current codegen.

Related: #15478.

Contributing

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Source: pulumi/pulumi