Hopefully fix terraform validate for aliased modules

Author: rfairburn

.github/workflows/tfvalidate.yml

@@ -76,5 +76,30 @@ jobs:
       - name: Validate ${{ matrix.terraform_dir }}  module (covers all submodules)
         working-directory: ${{ matrix.terraform_dir }}
         run: |
+          # Some modules use aliased AWS providers (for example aws.destination/aws.target)
+          # and fail direct `terraform validate` unless alias configs are present.
+          # Generate a temporary provider file for any discovered aws.<alias> references.
+          AWS_ALIASES="$(grep -RhoE 'provider[[:space:]]*=[[:space:]]*aws\.[A-Za-z0-9_]+' -- *.tf 2>/dev/null | sed -E 's/.*aws\.([A-Za-z0-9_]+)/\1/' | sort -u || true)"
+          if [[ -n "${AWS_ALIASES}" ]]; then
+            AUTO_PROVIDER_FILE=".tfvalidate.providers.auto.tf"
+            {
+              echo "// Generated by CI for terraform validate."
+              echo "// Do not commit."
+              echo
+            } > "${AUTO_PROVIDER_FILE}"
+
+            for alias in ${AWS_ALIASES}; do
+              cat >> "${AUTO_PROVIDER_FILE}" <<EOF
+provider "aws" {
+  alias  = "${alias}"
+  region = "us-east-2"
+}
+
+EOF
+            done
+
+            echo "Generated ${AUTO_PROVIDER_FILE} for aliases: ${AWS_ALIASES}"
+          fi
+
           terraform init -backend=false
           terraform validate