command/format: restore "(forces new resource)" caption

In 3ea1592 the plan rendering was refactored to add an extra indirection
of producing a display-oriented plan object first and then rendering from
that object.

There was a logic error while adapting the existing plan rendering code
to use the new display-oriented object: the core InstanceDiff object sets
the "Destroy" flag (a boolean) for both DiffDestroy and DiffDestroyCreate,
and so this code previously checked r.Destroy to recognize the
"destroy-create" case. This was incorrectly adapted to a check for the
display action being DiffDestroy, when it should actually have been
DiffDestroyCreate.

The effect of this bug was to cause the "(forces new resource)"
annotations to not be displayed on attributes, though the resource-level
information still correctly reflected that a new resource was required.

This fix restores the attribute-level annotations.

command/format/plan.go

@@ -311,7 +311,7 @@ func formatPlanInstanceDiff(buf *bytes.Buffer, r *InstanceDiff, keyLen int, colo
 
 		updateMsg := ""
 		switch {
-		case attr.ForcesNew && r.Action == terraform.DiffDestroy:
+		case attr.ForcesNew && r.Action == terraform.DiffDestroyCreate:
 			updateMsg = colorizer.Color(" [red](forces new resource)")
 		case attr.Sensitive && oldValues:
 			updateMsg = colorizer.Color(" [yellow](attribute changed)")

command/format/plan_test.go

@@ -509,6 +509,41 @@ func TestPlan_displayInterpolations(t *testing.T) {
 	}
 }
 
+// Ensure that (forces new resource) text is included
+// https://github.com/hashicorp/terraform/issues/16035
+func TestPlan_forcesNewResource(t *testing.T) {
+	plan := &terraform.Plan{
+		Diff: &terraform.Diff{
+			Modules: []*terraform.ModuleDiff{
+				&terraform.ModuleDiff{
+					Path: []string{"root"},
+					Resources: map[string]*terraform.InstanceDiff{
+						"test_resource.foo": &terraform.InstanceDiff{
+							Destroy: true,
+							Attributes: map[string]*terraform.ResourceAttrDiff{
+								"A": &terraform.ResourceAttrDiff{
+									New:         "B",
+									RequiresNew: true,
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+	dispPlan := NewPlan(plan)
+	actual := dispPlan.Format(disabledColorize)
+
+	expected := strings.TrimSpace(`
+-/+ test_resource.foo (new resource required)
+      A: "" => "B" (forces new resource)
+	`)
+	if actual != expected {
+		t.Fatalf("expected:\n\n%s\n\ngot:\n\n%s", expected, actual)
+	}
+}
+
 // Test that a root level data source gets a special plan output on create
 func TestPlan_rootDataSource(t *testing.T) {
 	plan := &terraform.Plan{