---
title: TFFR1 - Cross-Referencing Modules
description: Module Specification for the Azure Verified Modules (AVM) program
url: /spec/TFFR1
type: default
tags: [
  Class-Resource, # MULTIPLE VALUES: this can be "Class-Resource" AND/OR "Class-Pattern" AND/OR "Class-Utility"
  Class-Pattern, # MULTIPLE VALUES: this can be "Class-Resource" AND/OR "Class-Pattern" AND/OR "Class-Utility"
  Class-Utility, # MULTIPLE VALUES: this can be "Class-Resource" AND/OR "Class-Pattern" AND/OR "Class-Utility"
  Type-Functional, # SINGLE VALUE: this can be "Type-Functional" OR "Type-NonFunctional"
  Category-Naming/Composition, # SINGLE VALUE: this can be "Category-Testing" OR "Category-Telemetry" OR "Category-Contribution/Support" OR "Category-Documentation" OR "Category-CodeStyle" OR "Category-Naming/Composition" OR "Category-Inputs/Outputs" OR "Category-Release/Publishing"
  Language-Terraform, # MULTIPLE VALUES: this can be "Language-Bicep" AND/OR "Language-Terraform"
  Severity-MUST, # SINGLE VALUE: this can be "Severity-MUST" OR "Severity-SHOULD" OR "Severity-MAY"
  Persona-Owner, # MULTIPLE VALUES: this can be "Persona-Owner" AND/OR "Persona-Contributor"
  Persona-Contributor, # MULTIPLE VALUES: this can be "Persona-Owner" AND/OR "Persona-Contributor"
  Lifecycle-BAU, # SINGLE VALUE: this can be "Lifecycle-Initial" OR "Lifecycle-BAU" OR "Lifecycle-EOL"
  Validation-TBD # SINGLE VALUE: this can be "Validation-TF/Manual" OR "Validation-TF/CI/Informational" OR "Validation-TF/CI/Enforced"
]
priority: 20010
---

## ID: TFFR1 - Category: Composition - Cross-Referencing Modules

This requirement is enforced by [required_module_source_tffr1]({{% siteparam base %}}/contributing/terraform/tflint-rules/#required-module-source-tffr1).

Module owners **MAY** cross-references other modules to build either Resource or Pattern modules. However, they **MUST** be referenced only by a HashiCorp Terraform registry reference to a pinned version e.g.,

```terraform
module "other-module" {
  source  = "Azure/xxx/azure"
  version = "1.2.3"
}
```

They **MUST NOT** use git reference to a module.

```terraform
module "other-module" {
  source = "git::https://xxx.yyy/xxx.git"
}
```

```terraform
module "other-module" {
  source = "github.com/xxx/yyy"
}
```

Modules **MUST NOT** contain references to non-AVM modules.

{{% notice style="tip" %}}
See [Module Sources](https://developer.hashicorp.com/terraform/language/modules/sources) for more information.
{{% /notice %}}