Append warning in CLI output when query result is empty (#37379)

internal/command/query_test.go

@@ -5,6 +5,7 @@ package command
 
 import (
 	"path"
+	"strings"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
@@ -83,6 +84,15 @@ Error: Unsupported block type
 Blocks of type "resource" are not expected here.
 `},
 		},
+		{
+			name:      "empty result",
+			directory: "empty-result",
+			expectedOut: `list.test_instance.example   id=test-instance-1   Test Instance 1
+list.test_instance.example   id=test-instance-2   Test Instance 2
+
+Warning: list block(s) [list.test_instance.example2] returned 0 results.`,
+			initCode: 0,
+		},
 	}
 
 	for _, ts := range tests {
@@ -118,19 +128,22 @@ Blocks of type "resource" are not expected here.
 			args := []string{"-no-color"}
 			code = c.Run(args)
 			output = done(t)
-			actual := output.All()
 			if len(ts.expectedErr) == 0 {
 				if code != 0 {
 					t.Fatalf("bad: %d\n\n%s", code, output.Stderr())
 				}
+				actual := strings.TrimSpace(output.Stdout())
 
 				// Check that we have query output
-				if diff := cmp.Diff(ts.expectedOut, actual); diff != "" {
-					t.Errorf("expected query output to contain %q, \ngot: %q, \ndiff: %s", ts.expectedOut, actual, diff)
+				expected := strings.TrimSpace(ts.expectedOut)
+				if diff := cmp.Diff(expected, actual); diff != "" {
+					t.Errorf("expected query output to contain \n%q, \ngot: \n%q, \ndiff: %s", expected, actual, diff)
 				}
 
 			} else {
+				actual := strings.TrimSpace(output.Stderr())
 				for _, expected := range ts.expectedErr {
+					expected := strings.TrimSpace(expected)
 					if diff := cmp.Diff(expected, actual); diff != "" {
 						t.Errorf("expected error message to contain '%s', \ngot: %s, \ndiff: %s", expected, actual, diff)
 					}
@@ -228,11 +241,12 @@ func queryFixtureProvider() *testing_provider.MockProvider {
 
 		configMap := wholeConfigMap["config"]
 
-		// For empty results test case //TODO: Remove?
-		if ami, ok := wholeConfigMap["ami"]; ok && ami.AsString() == "ami-nonexistent" {
+		// For empty results test case
+		ami, ok := configMap.AsValueMap()["ami"]
+		if ok && ami.AsString() == "ami-nonexistent" {
 			return providers.ListResourceResponse{
 				Result: cty.ObjectVal(map[string]cty.Value{
-					"data":   cty.ListVal([]cty.Value{}),
+					"data":   cty.ListValEmpty(cty.DynamicPseudoType),
 					"config": configMap,
 				}),
 			}

internal/command/testdata/query/empty-result/main.tf

@@ -0,0 +1,13 @@
+terraform {
+  required_providers {
+    test = {
+      source = "hashicorp/test"
+    }
+  }
+}
+
+provider "test" {}
+
+resource "test_instance" "example" {
+  ami = "ami-12345"
+}

internal/command/testdata/query/empty-result/query.tfquery.hcl

@@ -0,0 +1,15 @@
+list "test_instance" "example" {
+  provider = test
+
+  config {
+    ami = "ami-12345"
+  }
+}
+
+list "test_instance" "example2" {
+  provider = test
+
+  config {
+    ami = "ami-nonexistent"
+  }
+}

internal/command/views/hook_json.go

@@ -263,6 +263,11 @@ func (h *jsonHook) PostListQuery(id terraform.HookResourceIdentity, results plan
 			json.MessageListResourceFound, result,
 		)
 	}
+	h.view.log.Info(
+		fmt.Sprintf("%s: List complete", addr.String()),
+		"type", json.MessageListComplete,
+		"total", data.LengthInt(),
+	)
 	return terraform.HookActionContinue, nil
 }
 

internal/command/views/hook_ui.go

@@ -534,7 +534,9 @@ func (h *UiHook) PostListQuery(id terraform.HookResourceIdentity, results plans.
 		result.WriteString(fmt.Sprintf("%s   %-*s   %s\n", addr.String(), maxIdentityLen, identity, displayNames[i]))
 	}
 
-	h.println(result.String())
+	if result.Len() > 0 {
+		h.println(result.String())
+	}
 
 	return terraform.HookActionContinue, nil
 }

internal/command/views/json/message_types.go

@@ -50,6 +50,7 @@ const (
 	// List messages
 	MessageListStart         MessageType = "list_start"
 	MessageListResourceFound MessageType = "list_resource_found"
+	MessageListComplete      MessageType = "list_complete"
 
 	// Action messages
 	MessageActionStart    MessageType = "action_start"

internal/command/views/query_operation.go

@@ -5,6 +5,7 @@ package views
 
 import (
 	"fmt"
+	"strings"
 
 	"github.com/hashicorp/terraform/internal/command/arguments"
 	"github.com/hashicorp/terraform/internal/command/format"
@@ -59,6 +60,31 @@ func (v *QueryOperationHuman) EmergencyDumpState(stateFile *statefile.File) erro
 }
 
 func (v *QueryOperationHuman) Plan(plan *plans.Plan, schemas *terraform.Schemas) {
+	// The hook for individual query blocks do not display any output when the results are empty,
+	// so we will display a grouped warning message here for the empty queries.
+	emptyBlocks := []string{}
+	for _, query := range plan.Changes.Queries {
+		pSchema := schemas.ProviderSchema(query.ProviderAddr.Provider)
+		addr := query.Addr
+		schema := pSchema.ListResourceTypes[addr.Resource.Resource.Type]
+
+		results, err := query.Decode(schema)
+		if err != nil {
+			v.view.streams.Eprintln(err)
+			continue
+		}
+
+		data := results.Results.Value.GetAttr("data")
+		if data.LengthInt() == 0 {
+			emptyBlocks = append(emptyBlocks, addr.String())
+		}
+
+	}
+
+	if len(emptyBlocks) > 0 {
+		msg := fmt.Sprintf(v.view.colorize.Color("[bold][yellow]Warning:[reset][bold] list block(s) [%s] returned 0 results.\n"), strings.Join(emptyBlocks, ", "))
+		v.view.streams.Println(format.WordWrap(msg, v.view.outputColumns()))
+	}
 }
 
 func (v *QueryOperationHuman) PlannedChange(change *plans.ResourceInstanceChangeSrc) {