What's New: Function Validation On by Default

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What changed

• Every TerraformStack checks the functions you use through Fn against your project’s declared targetVersions. If you don’t declare targetVersions, CDKTN checks against { "terraform": ">=1.5.7", "opentofu": ">=1.6.0" }.
• The validateFunctionVersions context key no longer has any effect. If your cdktf.json still sets it, CDKTN ignores it, whether it’s "true" or "false". You can’t turn the validation off with it anymore.
• cdktn init no longer adds the key to new projects.

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What you see

Validation failed with the following errors:
  [MyStack] Terraform function "templatestring" requires terraform >=1.9.0, but the project targets terraform >=1.5.7. It is available in terraform >=1.9.0 and opentofu >=1.7.0.
  [MyStack] Terraform function "templatestring" requires opentofu >=1.7.0, but the project targets opentofu >=1.6.0. It is available in terraform >=1.9.0 and opentofu >=1.7.0.

If you wish to ignore these validations, pass 'skipValidation: true' to your App configuration.

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How to fix a failure

• Raise the floor of each product you target to a version that has the function. For templatestring:
  {
    "targetVersions": {
      "terraform": ">=1.9.0",
      "opentofu": ">=1.7.0"
    }
  }
  
• Drop a product you don’t deploy with. If you only use OpenTofu, declare only opentofu. CDKTN then doesn’t check Terraform.
• Stop using the function, if you need to support older versions.
• Skip all validations with skipValidation: true on the App. This also turns off every other synth-time validation.