export Default to custom schema to help eliminate Optional attribut…

…e holding the default value

Makefile

@@ -1,2 +1,4 @@
+install:
+	@go install
 gen:
 	@./tools/generate-provider-schema/run.sh $(PROVIDER_DIR) $(PROVIDER_VERSION)

internal/hcl_schema.go

@@ -1,21 +1,63 @@
 package internal
 
 import (
+	"fmt"
+	"github.com/hashicorp/hcl/v2"
+	"strings"
+
 	"github.com/hashicorp/hcl/v2/hclwrite"
 	"github.com/magodo/aztfy/schema"
+	"github.com/zclconf/go-cty/cty"
 )
 
 // Currently, some special attributes are output by `terraform add`, while should be excluded.
 // This is tracked in: https://github.com/hashicorp/terraform/issues/29219
 // We are manually excluding these special properties here by modifying the hcl.
-func tuneHCLSchemaForResource(rb *hclwrite.Body, sch *schema.Schema) {
+func tuneHCLSchemaForResource(rb *hclwrite.Body, sch *schema.Schema) error {
 	rb.RemoveAttribute("id")
 	rb.RemoveBlock(rb.FirstMatchingBlock("timeouts", nil))
-	removeComputedForBody(rb, sch.Block)
+	return removeComputedForBody(rb, sch.Block)
 }
-func removeComputedForBody(rb *hclwrite.Body, sch *schema.SchemaBlock) {
-	for attrName := range rb.Attributes() {
-		if sch.Attributes[attrName].Computed {
+func removeComputedForBody(rb *hclwrite.Body, sch *schema.SchemaBlock) error {
+	for attrName, attrVal := range rb.Attributes() {
+		schAttr := sch.Attributes[attrName]
+		if schAttr.Required {
+			continue
+		}
+
+		if schAttr.Computed {
+			rb.RemoveAttribute(attrName)
+			continue
+		}
+
+		// For optional only attributes, remove it from the output config if it holds the default value
+		var dstr string
+		switch schAttr.AttributeType {
+		case cty.Number:
+			dstr = "0"
+		case cty.Bool:
+			dstr = "false"
+		case cty.String:
+			dstr = `""`
+		default:
+			if schAttr.AttributeType.IsListType() || schAttr.AttributeType.IsSetType() {
+				dstr = "[]"
+				break
+			}
+			if schAttr.AttributeType.IsMapType() {
+				dstr = "{}"
+				break
+			}
+		}
+		if schAttr.Default != nil {
+			dstr = fmt.Sprintf("%#v", schAttr.Default)
+		}
+		attrExpr, diags := hclwrite.ParseConfig(attrVal.BuildTokens(nil).Bytes(), "generate_attr", hcl.InitialPos)
+		if diags.HasErrors() {
+			return fmt.Errorf(`building attribute %q attribute: %s`, attrName, diags.Error())
+		}
+		attrValLit := strings.TrimSpace(string(attrExpr.Body().GetAttribute(attrName).Expr().BuildTokens(nil).Bytes()))
+		if attrValLit == dstr {
 			rb.RemoveAttribute(attrName)
 			continue
 		}
@@ -28,4 +70,5 @@ func removeComputedForBody(rb *hclwrite.Body, sch *schema.SchemaBlock) {
 		}
 		removeComputedForBody(blkVal.Body(), sch.NestedBlocks[blkVal.Type()].Block)
 	}
+	return nil
 }

schema/core_schema.go

@@ -88,6 +88,7 @@ func fromProviderSchemaAttribute(ps *schema.Schema) *SchemaAttribute {
 		Optional:      opt,
 		Required:      reqd,
 		Computed:      ps.Computed,
+		Default:       ps.Default,
 	}
 }
 

schema/schema.go

@@ -5,7 +5,7 @@ import "github.com/zclconf/go-cty/cty"
 // This is a simplified and modified version of the hashicorp/terraform-json.
 // The motivation for this is to add more information that is lost during the conversion from plugin sdk (v2) to the terraform core schema.
 // (github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema/core_schema.go)
-// Specifically, we are adding the Required, Optional, Computed for the SchemaBlockType, and removing any other attributes.
+// Specifically, we are adding the Required, Optional, Computed for the SchemaBlockType, adding Defualt for the SchemaAttribute, and removing any other attributes.
 
 type ProviderSchema struct {
 	ResourceSchemas map[string]*Schema `json:"resource_schemas,omitempty"`
@@ -32,7 +32,8 @@ type SchemaBlockType struct {
 type SchemaAttribute struct {
 	AttributeType cty.Type `json:"type,omitempty"`
 
-	Required bool `json:"required,omitempty"`
-	Optional bool `json:"optional,omitempty"`
-	Computed bool `json:"computed,omitempty"`
+	Required bool        `json:"required,omitempty"`
+	Optional bool        `json:"optional,omitempty"`
+	Computed bool        `json:"computed,omitempty"`
+	Default  interface{} `json:"default,omitempty"`
 }