Add custom_types config parameter

VERSION

@@ -1 +1 @@
-v2.0.2
+v2.1.0

config.go

@@ -135,6 +135,9 @@ type Config struct {
 	// should be used for the given package names, it can be used when the
 	// correct import path is not found automatically.
 	ImportPathOverrides map[string]string `yaml:"import_path_overrides,omitempty"`
+	// CustomTypes fields marks fields as custom types like the
+	// "gogoproto.customtype" tag would do.
+	CustomTypes map[string]string `yaml:"custom_types,omitempty"`
 
 	// params represents CLI params passed from the plugin
 	params map[string]string `yaml:"-"`

field_build_context.go

@@ -307,12 +307,17 @@ func (c *FieldBuildContext) IsMessage() bool {
 }
 
 // IsCustomType returns true if fields has gogo.custom_type flag
+// or if there's a custom type override in configuration.
 func (c *FieldBuildContext) IsCustomType() bool {
-	return c.field.IsCustomType()
+	_, ok := c.config.CustomTypes[c.GetPath()]
+	return c.field.IsCustomType() || ok
 }
 
 // GetCustomType returns true if fields has gogo.custom_type flag
 func (c *FieldBuildContext) GetCustomType() string {
+	if customType, ok := c.config.CustomTypes[c.GetPath()]; ok {
+		return customType
+	}
 	return c.field.GetCustomType()
 }
 

test/config.yaml

@@ -48,3 +48,6 @@ plan_modifiers:
 validators:
   "Test.Str":
     - UseMockValidator()
+
+custom_types:
+  "Test.StringOverride": StringCustom

test/copy_from_terraform_test.go

@@ -195,3 +195,12 @@ func TestCopyFromNullableEmbeddedFieldWithoutValue(t *testing.T) {
 	// should be nil
 	require.Nil(t, target.MaxAgeDuration)
 }
+
+func TestCopyFromStringOverride(t *testing.T) {
+	obj := copyFromTerraformObject(t)
+
+	target := Test{}
+	require.False(t, CopyTestFromTerraform(context.Background(), obj, &target).HasError())
+
+	require.Equal(t, "a/b/c", target.StringOverride)
+}

test/custom_types.go

@@ -3,6 +3,7 @@ package test
 import (
 	"context"
 	fmt "fmt"
+	"strings"
 	time "time"
 
 	"github.com/hashicorp/terraform-plugin-framework/attr"
@@ -78,3 +79,65 @@ func CopyToBoolSpecial(diags diag.Diagnostics, obj []BoolCustom, t attr.Type, v
 
 	return value
 }
+
+// StringCustom is a custom type that maps a Terraform List of string, onto a
+// single go string by joining all elements with "/".
+
+// GenSchemaStringCustom returns the StringCustom schema.
+func GenSchemaStringCustom(_ context.Context) tfsdk.Attribute {
+	return tfsdk.Attribute{
+		Type: types.ListType{
+			ElemType: types.StringType,
+		},
+	}
+}
+
+// CopyFromStringCustom copies the value from Terraform (a list of strings) into
+// the source (a single string) by joining all elements with "/".
+func CopyFromStringCustom(diags diag.Diagnostics, tf attr.Value, obj *string) {
+	v, ok := tf.(types.List)
+	if !ok {
+		diags.AddError("Error reading value from Terraform", fmt.Sprintf("Failed to cast %T to types.List", tf))
+		return
+	}
+
+	items := make([]string, 0)
+	for _, raw := range v.Elems {
+		el, ok := raw.(types.String)
+		if !ok {
+			diags.AddError("Error reading value from Terraform", fmt.Sprintf("Failed to cast %T to types.Bool", raw))
+			return
+		}
+
+		if !el.Null && !el.Unknown {
+			items = append(items, el.Value)
+		}
+	}
+
+	*obj = strings.Join(items, "/")
+}
+
+// CopyToStringCustom copies a source value (single string) into the Terraform
+// value (a list of strings) by splitting the string on every "/".
+func CopyToStringCustom(diags diag.Diagnostics, obj string, t attr.Type, v attr.Value) attr.Value {
+	value, ok := v.(types.List)
+	if !ok {
+		value = types.List{
+			Null:     true,
+			Unknown:  false,
+			ElemType: types.StringType,
+		}
+	}
+
+	if len(obj) > 0 {
+		if value.Elems == nil {
+			value.Elems = make([]attr.Value, len(obj))
+		}
+
+		for i, b := range strings.Split(obj, "/") {
+			value.Elems[i] = types.String{Null: false, Unknown: false, Value: b}
+		}
+	}
+
+	return value
+}

test/fixtures.go

@@ -423,6 +423,11 @@ func copyFromTerraformObject(t *testing.T) types.Object {
 				},
 			},
 			"max_age": DurationValue{Value: duration},
+			"string_override": types.List{Elems: []attr.Value{
+				types.String{Value: "a"},
+				types.String{Value: "b"},
+				types.String{Value: "c"},
+			}},
 		},
 		AttrTypes: obj.AttrTypes,
 	}

test/test.proto

@@ -166,6 +166,13 @@ message Test {
         (gogoproto.jsontag) = "",
         (gogoproto.embed) = true
       ];
+
+    // StringOverride is represented by a single string in the go struct, but by
+    // a list of strings in the Terraform Schema. The plugin's configuration
+    // specifies a custom_type (StringCustom), the generator should use the
+    // functions "GenSchemaStringCustom", "CopyFromStringCustom",
+    // "CopyToStringCustom" instead of attempting to generate them.
+    string StringOverride = 40;
 }
 
 message MaxAgeDuration {
@@ -223,4 +230,3 @@ message EmbeddedNestedField {
      // EmbeddedNestedString string field
     string EmbeddedNestedString = 1 [(gogoproto.jsontag) = "embedded_nested_string"];
   }
-