chore: add modernizer linter (#11936)

- Go has a suite of small linters that helps with modernizing Go code by using newer functions and catching small mistakes, https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/modernize.
- Enable this linter in golangci-lint.
- There's also [`go fix`](https://go.dev/blog/gofix), which is not yet released as a linter in golangci-lint: https://github.com/golangci/golangci-lint/pull/6385

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/11936
Reviewed-by: Mathieu Fenniak <mfenniak@noreply.codeberg.org>
Co-authored-by: Gusted <postmaster@gusted.xyz>
Co-committed-by: Gusted <postmaster@gusted.xyz>

modules/structs/action.go

@@ -70,13 +70,13 @@ type ActionRun struct {
 	// the current status of this run
 	Status string `json:"status"`
 	// when the action run was started
-	Started time.Time `json:"started,omitempty"`
+	Started time.Time `json:"started"`
 	// when the action run was stopped
-	Stopped time.Time `json:"stopped,omitempty"`
+	Stopped time.Time `json:"stopped"`
 	// when the action run was created
-	Created time.Time `json:"created,omitempty"`
+	Created time.Time `json:"created"`
 	// when the action run was last updated
-	Updated time.Time `json:"updated,omitempty"`
+	Updated time.Time `json:"updated"`
 	// how long the action run ran for
 	Duration time.Duration `json:"duration,omitempty"`
 	// the url of this action run

modules/structs/issue.go

@@ -204,7 +204,7 @@ func (l *IssueTemplateLabels) UnmarshalYAML(value *yaml.Node) error {
 		if err != nil {
 			return err
 		}
-		for _, v := range strings.Split(str, ",") {
+		for v := range strings.SplitSeq(str, ",") {
 			if v = strings.TrimSpace(v); v == "" {
 				continue
 			}

modules/structs/repo.go

@@ -118,7 +118,7 @@ type Repository struct {
 	// enum: ["sha1", "sha256"]
 	ObjectFormatName string `json:"object_format_name"`
 	// swagger:strfmt date-time
-	MirrorUpdated time.Time     `json:"mirror_updated,omitempty"`
+	MirrorUpdated time.Time     `json:"mirror_updated"`
 	RepoTransfer  *RepoTransfer `json:"repo_transfer"`
 	Topics        []string      `json:"topics"`
 }

modules/structs/user.go

@@ -34,9 +34,9 @@ type User struct {
 	// Is the user an administrator
 	IsAdmin bool `json:"is_admin"`
 	// swagger:strfmt date-time
-	LastLogin time.Time `json:"last_login,omitempty"`
+	LastLogin time.Time `json:"last_login"`
 	// swagger:strfmt date-time
-	Created time.Time `json:"created,omitempty"`
+	Created time.Time `json:"created"`
 	// Is user restricted
 	Restricted bool `json:"restricted"`
 	// Is user active

modules/structs/user_gpgkey.go

@@ -21,9 +21,9 @@ type GPGKey struct {
 	CanCertify        bool           `json:"can_certify"`
 	Verified          bool           `json:"verified"`
 	// swagger:strfmt date-time
-	Created time.Time `json:"created_at,omitempty"`
+	Created time.Time `json:"created_at"`
 	// swagger:strfmt date-time
-	Expires time.Time `json:"expires_at,omitempty"`
+	Expires time.Time `json:"expires_at"`
 }
 
 // GPGKeyEmail an email attached to a GPGKey

modules/structs/user_key.go

@@ -15,7 +15,7 @@ type PublicKey struct {
 	Title       string `json:"title,omitempty"`
 	Fingerprint string `json:"fingerprint,omitempty"`
 	// swagger:strfmt date-time
-	Created  time.Time `json:"created_at,omitempty"`
+	Created  time.Time `json:"created_at"`
 	Owner    *User     `json:"user,omitempty"`
 	ReadOnly bool      `json:"read_only,omitempty"`
 	KeyType  string    `json:"key_type,omitempty"`