Failing to resolve modules relative to the base module

[relu]

It seems there's an issue with how terragrunt-atlantis-config determines module paths when defined in child module .tf files.

The error:

$ terragrunt-atlantis-config_1.16.0_linux_amd64 generate --output atlantis.yaml --autoplan --parallel --create-workspace
INFO[0000] Could not find an old config file. Starting from scratch 
Error: Failed to read module directory: Module directory /tmp/terragrunt-atlantis-config-debug/account/region/env/sub-mod does not exist or cannot be read.

The configuration layout:

.
├── account
│   └── region
│       └── env
│           └── example
│               ├── example.tf
│               └── terragrunt.hcl
├── _modules
│   ├── example
│   │   └── main.tf
│   └── sub-mod
│       └── main.tf
└── terragrunt.hcl

7 directories, 5 files

Describing below the file contents for an example you can use.

• The root terragrunt.hcl file is empty
• The _modules/sub-mod/main.tf file is empty

# _modules/example/main.tf
module "example" {
  source = "../sub-mod"
}

# account/region/env/example/terragrunt.hcl
include {
  path = find_in_parent_folders()
}

terraform {
  source = "${get_parent_terragrunt_dir()}/_modules//example"
}

# account/region/env/example/example.tf
module "another" {
  source = "../sub-mod"
}

The problem is with the account/region/env/example/example.tf file which relies on a module that is relative to the parent module in _modules/sub-mod.
Note that this exact configuration works just fine with terragrunt itself (plan/apply).

I'm happy to provide more details if needed.

[Almenon]

I don't get it, why is there a terraform file in account/region/env/example/? I've never seen intermixing of Terragrunt and terraform in the same folder before. Also the source in account/region/env/example/example.tf points to a module that doesn't exist, account/region/env/sub-mod

[relu]

Because this is a feature of Terragrunt, it allows you to add or even override existing files from a base module and refer to resources from within the respective base module since it converges everything. Considering this, terragrunt will correctly evaluate the source relative path source = "../sub-mod" to the parent directory of the base module i.e. _modules/sub-mod and not account/region/env/sub-mod.

You can reproduce this using some null_resource definitions and use a similar file structure as given above, you will see Terragrunt will work correctly with these files while terragrunt-atlantis-config will fail.