schema: introduce lifecycle conditions

internal/schema/1.2/root.go

@@ -0,0 +1,115 @@
+package schema
+
+import (
+	"github.com/hashicorp/go-version"
+	"github.com/hashicorp/hcl-lang/lang"
+	"github.com/hashicorp/hcl-lang/schema"
+	"github.com/zclconf/go-cty/cty"
+
+	v015_mod "github.com/hashicorp/terraform-schema/internal/schema/0.15"
+)
+
+var v1_2 = version.Must(version.NewVersion("1.2.0"))
+
+func ModuleSchema(v *version.Version) *schema.BodySchema {
+	bs := v015_mod.ModuleSchema(v)
+	if v.GreaterThanOrEqual(v1_2) {
+		bs.Blocks["data"].Body.Blocks = map[string]*schema.BlockSchema{
+			"lifecycle": datasourceLifecycleBlock,
+		}
+		bs.Blocks["resource"].Body.Blocks["lifecycle"] = resourceLifecycleBlock
+		bs.Blocks["output"].Body.Blocks = map[string]*schema.BlockSchema{
+			"lifecycle": outputLifecycleBlock,
+		}
+	}
+
+	return bs
+}
+
+var datasourceLifecycleBlock = &schema.BlockSchema{
+	Description: lang.Markdown("Lifecycle customizations to set validity conditions of the datasource"),
+	Body: &schema.BodySchema{
+		Blocks: map[string]*schema.BlockSchema{
+			"precondition": {
+				Body: conditionBody,
+			},
+			"postcondition": {
+				Body: conditionBody,
+			},
+		},
+	},
+}
+
+var outputLifecycleBlock = &schema.BlockSchema{
+	Description: lang.Markdown("Lifecycle customizations, to set a validity condition of the output"),
+	Body: &schema.BodySchema{
+		Blocks: map[string]*schema.BlockSchema{
+			"precondition": {
+				Body: conditionBody,
+			},
+		},
+	},
+}
+
+var resourceLifecycleBlock = &schema.BlockSchema{
+	Description: lang.Markdown("Lifecycle customizations to change default resource behaviours during plan or apply"),
+	Body: &schema.BodySchema{
+		Attributes: map[string]*schema.AttributeSchema{
+			"create_before_destroy": {
+				Expr:       schema.LiteralTypeOnly(cty.Bool),
+				IsOptional: true,
+				Description: lang.Markdown("Whether to reverse the default order of operations (destroy -> create) during apply " +
+					"when the resource requires replacement (cannot be updated in-place)"),
+			},
+			"prevent_destroy": {
+				Expr:       schema.LiteralTypeOnly(cty.Bool),
+				IsOptional: true,
+				Description: lang.Markdown("Whether to prevent accidental destruction of the resource and cause Terraform " +
+					"to reject with an error any plan that would destroy the resource"),
+			},
+			"ignore_changes": {
+				Expr: schema.ExprConstraints{
+					schema.TupleConsExpr{},
+					schema.KeywordExpr{
+						Keyword: "all",
+						Description: lang.Markdown("Ignore all attributes, which means that Terraform can create" +
+							" and destroy the remote object but will never propose updates to it"),
+					},
+				},
+				IsOptional:  true,
+				Description: lang.Markdown("A set of fields (references) of which to ignore changes to, e.g. `tags`"),
+			},
+		},
+		Blocks: map[string]*schema.BlockSchema{
+			"precondition": {
+				Body: conditionBody,
+			},
+			"postcondition": {
+				Body: conditionBody,
+			},
+		},
+	},
+}
+
+var conditionBody = &schema.BodySchema{
+	Attributes: map[string]*schema.AttributeSchema{
+		"condition": {
+			Expr: schema.ExprConstraints{
+				schema.TraversalExpr{OfType: cty.Bool},
+				schema.LiteralTypeExpr{Type: cty.Bool},
+			},
+			IsRequired: true,
+			Description: lang.Markdown("Condition, a boolean expression that should return `true` " +
+				"if the intended assumption or guarantee is fulfilled or `false` if it is not."),
+		},
+		"error_message": {
+			Expr: schema.ExprConstraints{
+				schema.TraversalExpr{OfType: cty.String},
+				schema.LiteralTypeExpr{Type: cty.String},
+			},
+			IsRequired: true,
+			Description: lang.Markdown("Error message to return if the `condition` isn't met " +
+				"(evaluates to `false`)."),
+		},
+	},
+}

schema/core_schema.go

@@ -9,6 +9,7 @@ import (
 	mod_v0_13 "github.com/hashicorp/terraform-schema/internal/schema/0.13"
 	mod_v0_14 "github.com/hashicorp/terraform-schema/internal/schema/0.14"
 	mod_v0_15 "github.com/hashicorp/terraform-schema/internal/schema/0.15"
+	mod_v1_2 "github.com/hashicorp/terraform-schema/internal/schema/1.2"
 	universal "github.com/hashicorp/terraform-schema/internal/schema/universal"
 )
 
@@ -17,6 +18,7 @@ var (
 	v0_13 = version.Must(version.NewVersion("0.13"))
 	v0_14 = version.Must(version.NewVersion("0.14"))
 	v0_15 = version.Must(version.NewVersion("0.15"))
+	v1_2  = version.Must(version.NewVersion("1.2"))
 )
 
 // CoreModuleSchemaForVersion finds a module schema which is relevant
@@ -28,6 +30,9 @@ func CoreModuleSchemaForVersion(v *version.Version) (*schema.BodySchema, error)
 		return nil, fmt.Errorf("invalid version: %w", err)
 	}
 
+	if ver.GreaterThanOrEqual(v1_2) {
+		return mod_v1_2.ModuleSchema(ver), nil
+	}
 	if ver.GreaterThanOrEqual(v0_15) {
 		return mod_v0_15.ModuleSchema(ver), nil
 	}