Deprecation Warning For Outputs

internal/configs/named_values.go

@@ -345,12 +345,14 @@ type Output struct {
 	DependsOn   []hcl.Traversal
 	Sensitive   bool
 	Ephemeral   bool
+	Deprecated  string
 
 	Preconditions []*CheckRule
 
 	DescriptionSet bool
 	SensitiveSet   bool
 	EphemeralSet   bool
+	DeprecatedSet  bool
 
 	DeclRange hcl.Range
 }
@@ -402,6 +404,12 @@ func decodeOutputBlock(block *hcl.Block, override bool) (*Output, hcl.Diagnostic
 		o.EphemeralSet = true
 	}
 
+	if attr, exists := content.Attributes["deprecated"]; exists {
+		valDiags := gohcl.DecodeExpression(attr.Expr, nil, &o.Deprecated)
+		diags = append(diags, valDiags...)
+		o.DeprecatedSet = true
+	}
+
 	if attr, exists := content.Attributes["depends_on"]; exists {
 		deps, depsDiags := DecodeDependsOn(attr)
 		diags = append(diags, depsDiags...)
@@ -525,6 +533,9 @@ var outputBlockSchema = &hcl.BodySchema{
 		{
 			Name: "ephemeral",
 		},
+		{
+			Name: "deprecated",
+		},
 	},
 	Blocks: []hcl.BlockHeaderSchema{
 		{Type: "precondition"},

internal/configs/named_values_test.go

@@ -48,3 +48,30 @@ func TestVariableInvalidDefault(t *testing.T) {
 		}
 	}
 }
+
+func TestOutputDeprecation(t *testing.T) {
+	src := `
+		output "foo" {
+			value = "bar"
+			deprecated = "This output is deprecated"
+		}
+	`
+
+	hclF, diags := hclsyntax.ParseConfig([]byte(src), "test.tf", hcl.InitialPos)
+	if diags.HasErrors() {
+		t.Fatal(diags.Error())
+	}
+
+	b, diags := parseConfigFile(hclF.Body, nil, false, false)
+	if diags.HasErrors() {
+		t.Fatalf("unexpected error: %q", diags)
+	}
+
+	if !b.Outputs[0].DeprecatedSet {
+		t.Fatalf("expected output to be deprecated")
+	}
+
+	if b.Outputs[0].Deprecated != "This output is deprecated" {
+		t.Fatalf("expected output to have deprecation message")
+	}
+}

internal/lang/marks/marks.go

@@ -16,6 +16,11 @@ func (m valueMark) GoString() string {
 	return "marks." + string(m)
 }
 
+type DeprecationMark struct {
+	AttrPath cty.Path
+	Message  string
+}
+
 // Has returns true if and only if the cty.Value has the given mark.
 func Has(val cty.Value, mark valueMark) bool {
 	return val.HasMark(mark)

internal/plans/changes.go

@@ -617,16 +617,17 @@ func (c *Change) Encode(ty cty.Type) (*ChangeSrc, error) {
 	unmarkedAfter, marksesAfter := c.After.UnmarkDeepWithPaths()
 	sensitiveAttrsBefore, unsupportedMarksesBefore := marks.PathsWithMark(marksesBefore, marks.Sensitive)
 	sensitiveAttrsAfter, unsupportedMarksesAfter := marks.PathsWithMark(marksesAfter, marks.Sensitive)
+
 	if len(unsupportedMarksesBefore) != 0 {
 		return nil, fmt.Errorf(
-			"prior value %s: can't serialize value marked with %#v (this is a bug in Terraform)",
+			"prior value %s: cannot serialize value marked with %#v (this is a bug in Terraform)",
 			tfdiags.FormatCtyPath(unsupportedMarksesBefore[0].Path),
 			unsupportedMarksesBefore[0].Marks,
 		)
 	}
 	if len(unsupportedMarksesAfter) != 0 {
 		return nil, fmt.Errorf(
-			"new value %s: can't serialize value marked with %#v (this is a bug in Terraform)",
+			"new value %s: cannot serialize value marked with %#v (this is a bug in Terraform)",
 			tfdiags.FormatCtyPath(unsupportedMarksesAfter[0].Path),
 			unsupportedMarksesAfter[0].Marks,
 		)

internal/stacks/stackplan/planned_change.go

@@ -501,7 +501,7 @@ func DynamicValueToTerraform1(val cty.Value, ty cty.Type) (*stacks.DynamicValue,
 	sensitivePaths, withOtherMarks := marks.PathsWithMark(markPaths, marks.Sensitive)
 	if len(withOtherMarks) != 0 {
 		return nil, withOtherMarks[0].Path.NewErrorf(
-			"can't serialize value marked with %#v (this is a bug in Terraform)",
+			"cannot serialize value marked with %#v (this is a bug in Terraform)",
 			withOtherMarks[0].Marks,
 		)
 	}

internal/terraform/context_plan.go

@@ -349,7 +349,7 @@ The -target option is not for routine use, and is provided only for exceptional
 		panic("nil plan but no errors")
 	}
 
-	if plan != nil {
+	if plan != nil && plan.Changes != nil {
 		relevantAttrs, rDiags := c.relevantResourceAttrsForPlan(config, plan)
 		diags = diags.Append(rDiags)
 		plan.RelevantAttributes = relevantAttrs