chore(CI): Add a diff check for polymorph in CI

.github/actions/polymorph_codegen/action.yml

@@ -116,6 +116,12 @@ runs:
     #   run: |
     #     make polymorph_rust ${{ steps.dependencies.outputs.PROJECT_DEPENDENCIES }}
 
+    - name: Regenerate Go code using smithy-dafny
+      working-directory: ./${{ inputs.library }}
+      shell: bash
+      run: |
+        make polymorph_go
+
     - name: Check regenerated code against commited code
       # Composite action inputs seem to not actually support booleans properly for some reason
       if: inputs.diff-generated-code == 'true'

.github/workflows/library_codegen.yml

@@ -20,6 +20,7 @@ jobs:
         # Note dotnet is only used for formatting generated code
         # in this workflow
         dotnet-version: ["6.0.x"]
+        go-version: [1.23]
         os: [ubuntu-latest]
     runs-on: ${{ matrix.os }}
     defaults:
@@ -61,6 +62,15 @@ jobs:
       - name: Install Smithy-Dafny codegen dependencies
         uses: ./.github/actions/install_smithy_dafny_codegen_dependencies
 
+      - name: Install Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: ${{ matrix.go-version }}
+
+      - name: Install Go imports
+        run: |
+          go install golang.org/x/tools/cmd/goimports@latest
+
       - uses: ./.github/actions/polymorph_codegen
         with:
           dafny: ${{ env.DAFNY_VERSION }}

AwsEncryptionSDK/runtimes/go/examples/main.go

@@ -22,8 +22,8 @@ import (
 	"github.com/aws/aws-encryption-sdk-dafny/releases/go/encryption-sdk/examples/keyring/multikeyring"
 	"github.com/aws/aws-encryption-sdk-dafny/releases/go/encryption-sdk/examples/keyring/rawaeskeyring"
 	"github.com/aws/aws-encryption-sdk-dafny/releases/go/encryption-sdk/examples/keyring/rawrsakeyring"
-	"github.com/aws/aws-encryption-sdk-dafny/releases/go/encryption-sdk/examples/multithreading"
 	"github.com/aws/aws-encryption-sdk-dafny/releases/go/encryption-sdk/examples/misc"
+	"github.com/aws/aws-encryption-sdk-dafny/releases/go/encryption-sdk/examples/multithreading"
 	"github.com/aws/aws-encryption-sdk-dafny/releases/go/encryption-sdk/examples/utils"
 )