Remove dead code identified by deadcode tool (#37271)

Ran [`deadcode`](https://pkg.go.dev/golang.org/x/tools/cmd/deadcode)
(`-test ./...`) to find functions, methods and error types unreachable
from any call path (including tests), and removed the truly-dead ones.

Co-authored-by: Claude (Opus 4.7) <noreply@anthropic.com>

services/context/user.go

@@ -30,27 +30,6 @@ func UserAssignmentWeb() func(ctx *Context) {
 	}
 }
 
-// UserIDAssignmentAPI returns a middleware to handle context-user assignment for api routes
-func UserIDAssignmentAPI() func(ctx *APIContext) {
-	return func(ctx *APIContext) {
-		userID := ctx.PathParamInt64("user-id")
-
-		if ctx.IsSigned && ctx.Doer.ID == userID {
-			ctx.ContextUser = ctx.Doer
-		} else {
-			var err error
-			ctx.ContextUser, err = user_model.GetUserByID(ctx, userID)
-			if err != nil {
-				if user_model.IsErrUserNotExist(err) {
-					ctx.APIError(http.StatusNotFound, err)
-				} else {
-					ctx.APIErrorInternal(err)
-				}
-			}
-		}
-	}
-}
-
 // UserAssignmentAPI returns a middleware to handle context-user assignment for api routes
 func UserAssignmentAPI() func(ctx *APIContext) {
 	return func(ctx *APIContext) {

services/convert/secret.go

@@ -1,18 +0,0 @@
-// Copyright 2023 The Gitea Authors. All rights reserved.
-// SPDX-License-Identifier: MIT
-
-package convert
-
-import (
-	secret_model "code.gitea.io/gitea/models/secret"
-	api "code.gitea.io/gitea/modules/structs"
-)
-
-// ToSecret converts Secret to API format
-func ToSecret(secret *secret_model.Secret) *api.Secret {
-	result := &api.Secret{
-		Name: secret.Name,
-	}
-
-	return result
-}

services/forms/repo_form.go

@@ -740,14 +740,3 @@ func (f *AddTimeManuallyForm) Validate(req *http.Request, errs binding.Errors) b
 type SaveTopicForm struct {
 	Topics []string `binding:"topics;Required;"`
 }
-
-// DeadlineForm hold the validation rules for deadlines
-type DeadlineForm struct {
-	DateString string `form:"date" binding:"Required;Size(10)"`
-}
-
-// Validate validates the fields
-func (f *DeadlineForm) Validate(req *http.Request, errs binding.Errors) binding.Errors {
-	ctx := context.GetValidateContext(req)
-	return middleware.Validate(errs, ctx.Data, f, ctx.Locale)
-}

services/repository/files/content.go

@@ -32,11 +32,6 @@ const (
 	ContentTypeSubmodule ContentType = "submodule" // submodule content type (submodule)
 )
 
-// String gets the string of ContentType
-func (ct *ContentType) String() string {
-	return string(*ct)
-}
-
 type GetContentsOrListOptions struct {
 	TreePath                 string
 	IncludeSingleFileContent bool // include the file's content when the tree path is a file

services/repository/files/tree.go

@@ -26,12 +26,6 @@ type ErrSHANotFound struct {
 	SHA string
 }
 
-// IsErrSHANotFound checks if an error is a ErrSHANotFound.
-func IsErrSHANotFound(err error) bool {
-	_, ok := err.(ErrSHANotFound)
-	return ok
-}
-
 func (err ErrSHANotFound) Error() string {
 	return fmt.Sprintf("sha not found [%s]", err.SHA)
 }