Add warning when a cloud block is present in a child module

.changes/v1.13/BUG FIXES-20250529-163449.yaml

@@ -0,0 +1,5 @@
+kind: BUG FIXES
+body: 'Added a missing warning diagnostic that alerts users when child module contains an ignored `cloud` block.'
+time: 2025-05-29T16:34:49.041168+01:00
+custom:
+    Issue: "37180"

internal/configs/config_build.go

@@ -209,11 +209,20 @@ func loadModule(root *Config, req *ModuleRequest, walker ModuleWalker) (*Config,
 		diags = diags.Append(&hcl.Diagnostic{
 			Severity: hcl.DiagWarning,
 			Summary:  "Backend configuration ignored",
-			Detail:   "Any selected backend applies to the entire configuration, so Terraform expects provider configurations only in the root module.\n\nThis is a warning rather than an error because it's sometimes convenient to temporarily call a root module as a child module for testing purposes, but this backend configuration block will have no effect.",
+			Detail:   "Any selected backend applies to the entire configuration, so Terraform expects backend configurations only in the root module.\n\nThis is a warning rather than an error because it's sometimes convenient to temporarily call a root module as a child module for testing purposes, but this backend configuration block will have no effect.",
 			Subject:  mod.Backend.DeclRange.Ptr(),
 		})
 	}
 
+	if mod.CloudConfig != nil {
+		diags = diags.Append(&hcl.Diagnostic{
+			Severity: hcl.DiagWarning,
+			Summary:  "Cloud configuration ignored",
+			Detail:   "A cloud configuration block applies to the entire configuration, so Terraform expects 'cloud' blocks to only be in the root module.\n\nThis is a warning rather than an error because it's sometimes convenient to temporarily call a root module as a child module for testing purposes, but this cloud configuration block will have no effect.",
+			Subject:  mod.CloudConfig.DeclRange.Ptr(),
+		})
+	}
+
 	if len(mod.Import) > 0 {
 		diags = diags.Append(&hcl.Diagnostic{
 			Severity: hcl.DiagError,

internal/configs/config_build_test.go

@@ -127,7 +127,7 @@ func TestBuildConfigDiags(t *testing.T) {
 	}
 }
 
-func TestBuildConfigChildModuleBackend(t *testing.T) {
+func TestBuildConfigChildModule_Backend(t *testing.T) {
 	parser := NewParser(nil)
 	mod, diags := parser.LoadConfigDir("testdata/nested-backend-warning")
 	assertNoDiagnostics(t, diags)
@@ -170,6 +170,49 @@ func TestBuildConfigChildModuleBackend(t *testing.T) {
 	}
 }
 
+func TestBuildConfigChildModule_CloudBlock(t *testing.T) {
+	parser := NewParser(nil)
+	mod, diags := parser.LoadConfigDir("testdata/nested-cloud-warning")
+	assertNoDiagnostics(t, diags)
+	if mod == nil {
+		t.Fatal("got nil root module; want non-nil")
+	}
+
+	cfg, diags := BuildConfig(mod, ModuleWalkerFunc(
+		func(req *ModuleRequest) (*Module, *version.Version, hcl.Diagnostics) {
+			// For the sake of this test we're going to just treat our
+			// SourceAddr as a path relative to our fixture directory.
+			// A "real" implementation of ModuleWalker should accept the
+			// various different source address syntaxes Terraform supports.
+			sourcePath := filepath.Join("testdata/nested-cloud-warning", req.SourceAddr.String())
+
+			mod, diags := parser.LoadConfigDir(sourcePath)
+			version, _ := version.NewVersion("1.0.0")
+			return mod, version, diags
+		}),
+		MockDataLoaderFunc(func(provider *Provider) (*MockData, hcl.Diagnostics) {
+			return nil, nil
+		}),
+	)
+
+	assertDiagnosticSummary(t, diags, "Cloud configuration ignored")
+
+	// we should still have module structure loaded
+	var got []string
+	cfg.DeepEach(func(c *Config) {
+		got = append(got, fmt.Sprintf("%s %s", strings.Join(c.Path, "."), c.Version))
+	})
+	sort.Strings(got)
+	want := []string{
+		" <nil>",
+		"child 1.0.0",
+	}
+
+	if !reflect.DeepEqual(got, want) {
+		t.Fatalf("wrong result\ngot: %swant: %s", spew.Sdump(got), spew.Sdump(want))
+	}
+}
+
 func TestBuildConfigInvalidModules(t *testing.T) {
 	testDir := "testdata/config-diagnostics"
 	dirs, err := ioutil.ReadDir(testDir)