Getting error Argument or block definition required; An argument or block definition is required here

[Pardeep009]

We are submitting a file_name.hcl.json to atlantis, before plan and apply runs, pre-workflow-hook terragrunt-atlantis-config_1.14.2_linux_amd64 generate --output atlantis.yaml --parallel=false --autoplan --automerge --ignore-dependency-blocks=true runs which should have generated atlantis.yaml, but it didn't generate any such file and when I manually ran the pre-workflow-hook command it gave error as file_name.hcl.json:1,1-2: Argument or block definition required; An argument or block definition is required here.
content of file_name.hcl.json

{
  "include": [
    {
      "path": "${find_in_parent_folders()}"
    }
  ],
  "terraform": [
    {
      "source": "<referring some open source tf-module>"
    }
  ],
  "dependency": [
    {
      "project": [
        {
          "config_path": "${get_parent_terragrunt_dir()}/<referring project terragrunt file>"
        }
      ]
    }
  ],
  "inputs": {
    "a" : "b",
    "c" : "d"
  }
}

but if I run terragrunt plan locally in that file location it works.
captured server logs from atlantis when file_name.hcl.json is submitted

Aug 24 19:40:50 atlantis-vm atlantis[93604]: {"level":"info","ts":"2022-08-24T19:40:50.484Z","caller":"server/server.go:864","msg":"Apply Lock: {false 0001-01-01 00:00:00 +0000 UTC }","json":{}}
Aug 24 19:40:51 atlantis-vm atlantis[93604]: {"level":"info","ts":"2022-08-24T19:40:51.523Z","caller":"server/server.go:864","msg":"Apply Lock: {false 0001-01-01 00:00:00 +0000 UTC }","json":{}}
Aug 24 19:40:53 atlantis-vm atlantis[93604]: {"level":"info","ts":"2022-08-24T19:40:53.534Z","caller":"server/server.go:864","msg":"Apply Lock: {false 0001-01-01 00:00:00 +0000 UTC }","json":{}}
Aug 24 19:40:54 atlantis-vm atlantis[93604]: {"level":"info","ts":"2022-08-24T19:40:54.983Z","caller":"events/events_controller.go:461","msg":"identified event as type \"updated\"","json":{}}
Aug 24 19:40:54 atlantis-vm atlantis[93604]: {"level":"info","ts":"2022-08-24T19:40:54.983Z","caller":"events/events_controller.go:346","msg":"executing autoplan","json":{}}
Aug 24 19:40:55 atlantis-vm atlantis[93604]: {"level":"info","ts":"2022-08-24T19:40:55.013Z","caller":"events/working_dir.go:202","msg":"creating dir \"/opt/atlantis/.atlantis/repos/iac/iac/XXX/default\"","json":{"repo":"iac/iac","pull":"XXX"}}
Aug 24 19:40:55 atlantis-vm atlantis[93604]: {"level":"info","ts":"2022-08-24T19:40:55.483Z","caller":"server/server.go:864","msg":"Apply Lock: {false 0001-01-01 00:00:00 +0000 UTC }","json":{}}
Aug 24 19:40:56 atlantis-vm atlantis[93604]: {"level":"info","ts":"2022-08-24T19:40:56.523Z","caller":"server/server.go:864","msg":"Apply Lock: {false 0001-01-01 00:00:00 +0000 UTC }","json":{}}
Aug 24 19:40:58 atlantis-vm atlantis[93604]: {"level":"info","ts":"2022-08-24T19:40:58.533Z","caller":"server/server.go:864","msg":"Apply Lock: {false 0001-01-01 00:00:00 +0000 UTC }","json":{}}
Aug 24 19:41:00 atlantis-vm atlantis[93604]: {"level":"info","ts":"2022-08-24T19:41:00.483Z","caller":"server/server.go:864","msg":"Apply Lock: {false 0001-01-01 00:00:00 +0000 UTC }","json":{}}
Aug 24 19:41:00 atlantis-vm atlantis[93604]: {"level":"error","ts":"2022-08-24T19:41:00.606Z","caller":"events/command_runner.go:159","msg":"Error running pre-workflow hooks exit status 1: running \"terragrunt-atlantis-config_1.14.2_linux_amd64 generate --output atlantis.yaml  --parallel=false --autoplan --automerge --ignore-dependency-blocks=true\" in \"/opt/atlantis/.atlantis/repos/iac/iac/XXX/default\": \ntime=\"2022-08-24T19:40:55Z\" level=info msg=\"Could not find an old config file. Starting from scratch\"\ntime=\"2022-08-24T19:40:55Z\" level=info msg=\"Created project for /opt/atlantis/.atlantis/repos/iac/iac/XXX/default/terragrunt.hcl\"\ntime=\"2022-08-24T19:40:55Z\" ...."}
Aug 24 19:41:00 atlantis-vm atlantis[93604]: {"level":"info","ts":"2022-08-24T19:41:00.975Z","caller":"events/project_command_builder.go:266","msg":"found no atlantis.yaml file","json":{"repo":"iac/iac","pull":"584"}}
Aug 24 19:41:00 atlantis-vm atlantis[93604]: {"level":"info","ts":"2022-08-24T19:41:00.975Z","caller":"events/project_command_builder.go:271","msg":"automatically determined that there were 0 projects modified in this pull request: []","json":{"repo":"iac/iac","pull":"584"}}
Aug 24 19:41:00 atlantis-vm atlantis[93604]: {"level":"info","ts":"2022-08-24T19:41:00.975Z","caller":"events/plan_command_runner.go:84","msg":"determined there was no project to run plan in","json":{"repo":"iac/iac","pull":"584"}}
Aug 24 19:41:01 atlantis-vm atlantis[93604]: {"level":"info","ts":"2022-08-24T19:41:01.522Z","caller":"server/server.go:864","msg":"Apply Lock: {false 0001-01-01 00:00:00 +0000 UTC }","json":{}}
Aug 24 19:41:03 atlantis-vm atlantis[93604]: {"level":"info","ts":"2022-08-24T19:41:03.533Z","caller":"server/server.go:864","msg":"Apply Lock: {false 0001-01-01 00:00:00 +0000 UTC }","json":{}}
Aug 24 19:41:05 atlantis-vm atlantis[93604]: {"level":"info","ts":"2022-08-24T19:41:05.483Z","caller":"server/server.go:864","msg":"Apply Lock: {false 0001-01-01 00:00:00 +0000 UTC }","json":{}}
Aug 24 19:41:06 atlantis-vm atlantis[93604]: {"level":"info","ts":"2022-08-24T19:41:06.523Z","caller":"server/server.go:864","msg":"Apply Lock: {false 0001-01-01 00:00:00 +0000 UTC }","json":{}}

[maitreya-source]

I was able to replicate this issue and tried to do some root cause analysis. My understanding of the issue is as follows:

Underlying issue

• hclwrite library used in parse_hcl.go is unable to read files converted from json to hcl via JSONparser.
  • Checkout terragrunt issue #1951: JSON parsing to hcl broken after 0.32.6.

Context

• As per my understanding and debugging, this tool works as follows:

flowchart TB
    subgraph generate.go
    main-- for every hcl/json file --> createProject --> getDependencies
    end
    subgraph parse_hcl.go
    getDependencies-->parseModule
    parseModule-->decodeAsTerragruntInclude
    decodeAsTerragruntInclude--decodes only the `include` blocks using-->decodeHcl
    decodeHcl--calls to check bare include blocks-->updateBareIncludeBlock
    end
    subgraph parse_locals.go
    decodeHcl--if configuration updated by updateBareInlucdeBlock: reparse hcl using-->parseHcl
    parseModule--calls to parse hcl-->parseHcl
    end
    subgraph hclWrite_library
    updateBareIncludeBlock--calls to update bare include blocks-->ParseConfig
    end

• During the course of execution, the tool checks if include blocks in terragrunt have a label or not. If there is no label, it calls updateBareIncludeBlock to update the bare include blocks with an empty label ("") .
• It uses hclwrite to update the bare include blocks.
• However, due to the bug in the hclWrite library, when the hcl objects converted from .hcl.json file are passed as input to hclWrite, it throws following error:

Error: file_name.hcl.json:1,1-2: Argument or block definition required; An argument or block definition is required here.

Possible fix/workaround?

• We can skip calling updateBareIncludeBlock function for .hcl.json file formats. Which in-turn will skip the call to hclwrite for the hcl objects generated from .hcl.json files.

• This is just a workaround, until terragrunt issue #1951: JSON parsing to hcl broken after 0.32.6 is fixed.

• Users will need to specify include blocks with labels in terragrunt.hcl.json. The label can be an empty string ("") as well:

  "include": [
    {
      "": [     "<-- Note the addition of a bare string."
        {
            "path": "${find_in_parent_folders()}"
        }
      ]
    }
  ],  

Raising a pull request with the workaround.