Dynamic Pseudo Types inside of Blocks with nested mode of list cant be unmarshalled to tfvalues

[Nciso]

terraform-plugin-go version

v0.14.3

Relevant provider source code

// this is making a panic, not even  getting to an error
values, err := req.Config.Unmarshal(tftypes.Object{
   // objTypeDef.AttributeTypes is the result of calling ValueType() on  a  tfprotov5.Schema
    AttributeTypes: objTypeDef.AttributeTypes
})


// this is the tfprotov5 schema

    tfprotov5.Schema{
		Version: 1,
		Block: &tfprotov5.SchemaBlock{
			Version: 1,
			Attributes: []*tfprotov5.SchemaAttribute{
				{
					Name:     "id",
					Type:     tftypes.String,
					Computed: true,
				},
				{
					Name:     "regular_attribute",
					Type:     tftypes.String,
					Optional: true,
				},
				{
					Name:     "dynamic_attribute",
					Type:     tftypes.DynamicPseudoType,
					Optional: true,
				},
			},
			BlockTypes: []*tfprotov5.SchemaNestedBlock{
				{
					TypeName: "dynamic_block",
					Nesting:  tfprotov5.SchemaNestedBlockNestingModeList,
					Block: &tfprotov5.SchemaBlock{
						Attributes: []*tfprotov5.SchemaAttribute{
							{
								Name:     "bar",
								Type:     tftypes.DynamicPseudoType,
								Optional: true,
							},
							{
								Name:     "foo",
								Type:     tftypes.Number,
								Optional: true,
							},
						},
					},
				},
				{
					TypeName: "regular_block",
					Nesting:  tfprotov5.SchemaNestedBlockNestingModeList,
					Block: &tfprotov5.SchemaBlock{
						Attributes: []*tfprotov5.SchemaAttribute{
							{
								Name:     "bar",
								Type:     tftypes.String,
								Optional: true,
							},
							{
								Name:     "foo",
								Type:     tftypes.Number,
								Optional: true,
							},
						},
					},
				},
			},
		},
	}

E2E test https://github.com/Nciso/low_level_provider_example/blob/main/internal/data_dummy/dummy_data_test.go#L17

Terraform Configuration Files

data "provider_dummy" "test" {
  dynamic_attribute = "hello"
  regular_attribute = "bye"
  regular_block {
    bar = "bar"
    foo = 3
  }
  dynamic_block {
    bar = "bar"
    foo = 4
  }
}

Expected Behavior

it should be able to create a statefile, this behavior is happening if your remove the DPT of the dynamic_block schema and change it to a string, (tftypes.String instead of tftypes.DynamicPseudoType )

Actual Behavior

A panic is produced

2023-02-28T17:19:19.961-0600 [ERROR] sdk.proto: Error from downstream: tf_proto_version=5.3 tf_rpc=ReadDataSource tf_data_source_type=provider_dummy tf_req_id=4939bb6e-c465-28c6-470f-5a42012f85e4 error="Cant unmarshall config input, AttributeName(\"dynamic_block\").ElementKeyInt(0): error decoding object length: msgpack: invalid code=c4 decoding map length" tf_provider_addr=registry.terraform.io/hashicorp/provider
    provider_low_example/internal/data_dummy/dummy_data_test.go:21: Step 1/1 error: Error running pre-apply refresh: exit status 1

        Error: Plugin error

          with data.provider_dummy.test,
          on terraform_plugin_test.tf line 3, in data "provider_dummy" "test":
           3:   data "provider_dummy" "test" {

        The plugin returned an unexpected error from
        plugin.(*GRPCProvider).ReadDataSource: rpc error: code = Unknown desc = Cant
        unmarshall config input, AttributeName("dynamic_block").ElementKeyInt(0):
        error decoding object length: msgpack: invalid code=c4 decoding map length

Steps to Reproduce

Run the following test

https://github.com/Nciso/low_level_provider_example/blob/main/internal/data_dummy/dummy_data_test.go#L17

References

Inspecting with the debugger I found the following:

• Changing the nesting mode in the block attributes changes the behavior of the types

  • set won't accept dynamic pseudotypes
  • list accept them, but the lib that is unmarshalling the bytes from the RCP (github.com/vmihailenco/msgpack/v4) is having problems reading the decoded state
  • it is raising a panic because it cant parse the hex value of 0xC4, which is what is passing the length value of the list
    fail decoding, testName: decoded_with_dpt_block error -> AttributeName("dynamic_block"): error decoding object length: msgpack: invalid code=92 decoding map length

• When the terraform core code is reached, there is a conversion from the schema to a cty.Value, if a block contains a DPT it will change the whole root attribute of the block to a DTP instead of changing the local attribute, https://github.com/hashicorp/terraform-plugin-sdk/blob/main/internal/configs/configschema/implied_type.go#L40

• Also this is the code that is not allowing DPT in sets, https://github.com/hashicorp/terraform-plugin-sdk/blob/main/internal/configs/configschema/implied_type.go#L47

• Once the cty value reaches to objchange in the terraform plan time, it panics because the cty.object was transformed to a cty.dynamicPseudoType in the above step https://github.com/hashicorp/terraform/blob/main/internal/plans/objchange/objchange.go#L71

[tyler-dunkel]

Hi, encountering a similar issue and wondering if there were any updates here? Thanks!

[frezbo]

There seems to be a similar issue with using DynamicPseudoType with tftypes.List

                                                  {
							Name: "config_patches",
							Type: tftypes.List{
								ElementType: tftypes.DynamicPseudoType,
							},
							Optional:    true,
						},

this returns an error way earlier in plan

│ Inappropriate value for attribute "config_patches": all list elements must have the same
│ type.

when using tftypes.Tuple to work around the problem, the doc generation fails https://github.com/hashicorp/terraform-plugin-docs/blob/dc2adaa2368d68ece586a9e49cd4bc75924148cf/schemamd/render.go#L83