Preserve output type when generating metadata without --generate-outp…

…ut-type flag

cli/bpmetadata/cmd.go

@@ -256,6 +256,9 @@ func CreateBlueprintMetadata(bpPath string, bpMetadataObj *BlueprintMetadata) (*
 	// Merge existing connections (if any) into the newly generated interfaces
 	mergeExistingConnections(bpMetadataObj.Spec.Interfaces, existingInterfaces)
 
+	// Merge existing output types (if any) into the newly generated interfaces
+	mergeExistingOutputTypes(bpMetadataObj.Spec.Interfaces, existingInterfaces)
+
 	// get blueprint requirements
 	rolesCfgPath := path.Join(repoDetails.Source.BlueprintRootPath, tfRolesFileName)
 	svcsCfgPath := path.Join(repoDetails.Source.BlueprintRootPath, tfServicesFileName)

cli/bpmetadata/tfconfig.go

@@ -522,6 +522,25 @@ func mergeExistingConnections(newInterfaces, existingInterfaces *BlueprintInterf
 	}
 }
 
+// mergeExistingOutputTypes merges existing output types from an old BlueprintInterface into a new one,
+// preserving manually authored types.
+func mergeExistingOutputTypes(newInterfaces, existingInterfaces *BlueprintInterface) {
+	if existingInterfaces == nil {
+		return // Nothing to merge if existingInterfaces is nil
+	}
+
+	existingOutputs := make(map[string]*BlueprintOutput)
+	for _, output := range existingInterfaces.Outputs {
+		existingOutputs[output.Name] = output
+	}
+
+	for i, output := range newInterfaces.Outputs {
+		if existingOutput, ok := existingOutputs[output.Name]; ok && existingOutput.Type != nil {
+			newInterfaces.Outputs[i].Type = existingOutput.Type
+		}
+	}
+}
+
 // UpdateOutputTypes generates the terraform.tfstate file, extracts output types from it,
 // and updates the output types in the provided BlueprintInterface.
 func updateOutputTypes(bpPath string, bpInterfaces *BlueprintInterface) error {

cli/bpmetadata/tfconfig_test.go

@@ -346,6 +346,48 @@ func TestMergeExistingConnections(t *testing.T) {
 	}
 }
 
+func TestMergeExistingOutputTypes(t *testing.T) {
+	tests := []struct {
+		name                   string
+		newInterfacesFile      string
+		existingInterfacesFile string
+	}{
+		{
+			name:                   "No existing types",
+			newInterfacesFile:      "interfaces_without_output_types_metadata.yaml",
+			existingInterfacesFile: "interfaces_without_output_types_metadata.yaml",
+		},
+		{
+			name:                   "One complex existing type is preserved",
+			newInterfacesFile:      "interfaces_without_output_types_metadata.yaml",
+			existingInterfacesFile: "interfaces_with_partial_output_types_metadata.yaml",
+		},
+		{
+			name:                   "All existing types (both simple and complex) are preserved",
+			newInterfacesFile:      "interfaces_without_output_types_metadata.yaml",
+			existingInterfacesFile: "interfaces_with_full_output_types_metadata.yaml",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Load new interfaces from file
+			newInterfaces, err := UnmarshalMetadata(metadataTestdataPath, tt.newInterfacesFile)
+			require.NoError(t, err)
+
+			// Load existing interfaces from file
+			existingInterfaces, err := UnmarshalMetadata(metadataTestdataPath, tt.existingInterfacesFile)
+			require.NoError(t, err)
+
+			// Perform the merge
+			mergeExistingOutputTypes(newInterfaces.Spec.Interfaces, existingInterfaces.Spec.Interfaces)
+
+			// Assert that the merged interfaces match the expected outcome
+			assert.Equal(t, existingInterfaces.Spec.Interfaces, newInterfaces.Spec.Interfaces)
+		})
+	}
+}
+
 func TestTFIncompleteProviderVersions(t *testing.T) {
 	tests := []struct {
 		name       string
@@ -429,7 +471,7 @@ func TestUpdateOutputTypes(t *testing.T) {
 		{
 			name:           "Update output types from state",
 			bpPath:         "sample-module",
-			interfacesFile: "interfaces_without_types_metadata.yaml",
+			interfacesFile: "interfaces_without_output_types_metadata.yaml",
 			stateFile:      "terraform.tfstate",
 			expectedOutputs: []*BlueprintOutput{
 				{

cli/testdata/bpmetadata/metadata/interfaces_with_full_output_types_metadata.yaml

@@ -0,0 +1,17 @@
+apiVersion: blueprints.cloud.google.com/v1alpha1
+kind: BlueprintMetadata
+metadata:
+  name: terraform-google-network
+spec:
+  interfaces:
+    outputs:
+    - name: cluster_id
+      description: Cluster ID
+      type: string 
+    - name: endpoint
+      description: Cluster endpoint
+      type: 
+        - list
+        - - object:
+          - host: string
+            port: number

cli/testdata/bpmetadata/metadata/interfaces_with_partial_output_types_metadata.yaml

@@ -0,0 +1,16 @@
+apiVersion: blueprints.cloud.google.com/v1alpha1
+kind: BlueprintMetadata
+metadata:
+  name: terraform-google-network
+spec:
+  interfaces:
+    outputs:
+    - name: cluster_id
+      description: Cluster ID
+    - name: endpoint
+      description: Cluster endpoint
+      type: 
+        - list
+        - - object:
+          - host: string
+            port: number

cli/testdata/bpmetadata/metadata/interfaces_without_types_metadata.yaml → cli/testdata/bpmetadata/metadata/interfaces_without_output_types_metadata.yaml

@@ -1,4 +1,4 @@
-# interfaces_without_types_metadata.yaml
+# interfaces_without_output_types_metadata.yaml
 apiVersion: blueprints.cloud.google.com/v1alpha1
 kind: BlueprintMetadata
 metadata: