fix(xerrors): rename MarshalJSON field platformCode → platform_code (#3)

JSON tag on the anonymous struct inside MarshalJSON corrected from
`json:"platformCode,omitempty"` to `json:"platform_code,omitempty"` to
match the OpenAPI spec snake_case convention. All error responses that
serialize *Err directly now emit "platform_code" instead of "platformCode".
PR.md added to .gitignore.

Reviewed-on: #3
Co-authored-by: Rene Nochebuena Guerrero <rene@nochebuena.dev>
Co-committed-by: Rene Nochebuena Guerrero <rene@nochebuena.dev>

.gitignore

@@ -36,3 +36,4 @@ Thumbs.db
 # VCS files
 COMMIT.md
 RELEASE.md
+PR.md

CHANGELOG.md

@@ -5,6 +5,33 @@ All notable changes to this module will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this module adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.0.2] - 2026-05-22
+
+### Fixed
+
+- `MarshalJSON` JSON tag corrected from `"platformCode"` to `"platform_code"` to
+  match the OpenAPI spec snake_case convention.
+
+[1.0.2]: https://code.nochebuena.dev/go/xerrors/compare/v1.0.1...v1.0.2
+
+## [1.0.0] — 2026-05-08
+
+### Added
+
+- `Unauthorized(msg string, args ...any) *Err` — convenience constructor for
+  `ErrUnauthorized`; completes the set of the five most-used codes alongside
+  `InvalidInput`, `NotFound`, `Internal`, and `PermissionDenied`
+- `PermissionDenied(msg string, args ...any) *Err` — convenience constructor for
+  `ErrPermissionDenied`
+
+### Unchanged
+
+All existing API (`Code`, `Err`, `New`, `Wrap`, `InvalidInput`, `NotFound`,
+`Internal`, `WithContext`, `WithError`, `WithPlatformCode`, `ErrorCode`,
+`ErrorContext`, `MarshalJSON`) is API-compatible with v0.10.0.
+
+[1.0.0]: https://code.nochebuena.dev/go/xerrors/releases/tag/v1.0.0
+
 ## [0.10.0] - 2026-03-25
 
 ### Added

go.mod

@@ -1,3 +1,3 @@
 module code.nochebuena.dev/go/xerrors
 
-go 1.25
+go 1.26

xerrors.go

@@ -67,6 +67,18 @@ func Internal(msg string, args ...any) *Err {
 	return New(ErrInternal, fmt.Sprintf(msg, args...))
 }
 
+// Unauthorized creates an Err with [ErrUnauthorized] code.
+// msg is formatted with args using [fmt.Sprintf] rules.
+func Unauthorized(msg string, args ...any) *Err {
+	return New(ErrUnauthorized, fmt.Sprintf(msg, args...))
+}
+
+// PermissionDenied creates an Err with [ErrPermissionDenied] code.
+// msg is formatted with args using [fmt.Sprintf] rules.
+func PermissionDenied(msg string, args ...any) *Err {
+	return New(ErrPermissionDenied, fmt.Sprintf(msg, args...))
+}
+
 // WithContext adds a key-value pair to the error's context fields and returns
 // the receiver for chaining. Calling it multiple times with the same key
 // overwrites the previous value.
@@ -176,12 +188,12 @@ func (e *Err) ErrorContext() map[string]any {
 }
 
 // MarshalJSON implements [json.Marshaler].
-// Output: {"code":"NOT_FOUND","platformCode":"EMPLOYEE_NOT_FOUND","message":"...","fields":{...}}
-// platformCode and fields are omitted when empty.
+// Output: {"code":"NOT_FOUND","platform_code":"IDG-USR-0004","message":"...","fields":{...}}
+// platform_code and fields are omitted when empty.
 func (e *Err) MarshalJSON() ([]byte, error) {
 	return json.Marshal(struct {
 		Code         string         `json:"code"`
-		PlatformCode string         `json:"platformCode,omitempty"`
+		PlatformCode string         `json:"platform_code,omitempty"`
 		Message      string         `json:"message"`
 		Fields       map[string]any `json:"fields,omitempty"`
 	}{

xerrors_test.go

@@ -70,6 +70,26 @@ func TestConvenienceConstructors(t *testing.T) {
 			t.Errorf("unexpected message: %s", err.message)
 		}
 	})
+
+	t.Run("Unauthorized", func(t *testing.T) {
+		err := Unauthorized("token expired for %s", "uid1")
+		if err.code != ErrUnauthorized {
+			t.Errorf("expected code %s, got %s", ErrUnauthorized, err.code)
+		}
+		if err.message != "token expired for uid1" {
+			t.Errorf("unexpected message: %s", err.message)
+		}
+	})
+
+	t.Run("PermissionDenied", func(t *testing.T) {
+		err := PermissionDenied("role %s cannot delete", "viewer")
+		if err.code != ErrPermissionDenied {
+			t.Errorf("expected code %s, got %s", ErrPermissionDenied, err.code)
+		}
+		if err.message != "role viewer cannot delete" {
+			t.Errorf("unexpected message: %s", err.message)
+		}
+	})
 }
 
 func TestErr_Error(t *testing.T) {
@@ -292,8 +312,8 @@ func TestErr_MarshalJSON_PlatformCode(t *testing.T) {
 		if jsonErr = json.Unmarshal(b, &out); jsonErr != nil {
 			t.Fatalf("unmarshal error: %v", jsonErr)
 		}
-		if out["platformCode"] != "EMPLOYEE_NOT_FOUND" {
-			t.Errorf("json platformCode = %v, want EMPLOYEE_NOT_FOUND", out["platformCode"])
+		if out["platform_code"] != "EMPLOYEE_NOT_FOUND" {
+			t.Errorf("json platform_code = %v, want EMPLOYEE_NOT_FOUND", out["platform_code"])
 		}
 	})
 
@@ -303,8 +323,8 @@ func TestErr_MarshalJSON_PlatformCode(t *testing.T) {
 		if jsonErr != nil {
 			t.Fatalf("MarshalJSON error: %v", jsonErr)
 		}
-		if strings.Contains(string(b), "platformCode") {
-			t.Errorf("json should omit platformCode when empty, got: %s", b)
+		if strings.Contains(string(b), "platform_code") {
+			t.Errorf("json should omit platform_code when empty, got: %s", b)
 		}
 	})
 }