Clean-up HookPreReceive and restore functionality for pushing non-standard refs

There was an inadvertent breaking change in go-gitea#15629 meaning that notes refs and other
git extension refs will be automatically rejected.

Further following go-gitea#14295 and go-gitea#15629 the pre-recieve hook code is untenably long and
too complex.

This PR refactors the hook code and removes the incorrect forced rejection of
non-standard refs.

Fix go-gitea#16688

Signed-off-by: Andrew Thornton <[email protected]>

Author: zeripath

routers/private/default_branch.go

@@ -0,0 +1,75 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+// Package private includes all internal routes. The package name internal is ideal but Golang is not allowed, so we use private as package name instead.
+package private
+
+import (
+	"fmt"
+	"net/http"
+
+	"code.gitea.io/gitea/models"
+	gitea_context "code.gitea.io/gitea/modules/context"
+	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/private"
+)
+
+// ________          _____             .__   __
+// \______ \   _____/ ____\____   __ __|  |_/  |_
+//  |    |  \_/ __ \   __\\__  \ |  |  \  |\   __\
+//  |    `   \  ___/|  |   / __ \|  |  /  |_|  |
+// /_______  /\___  >__|  (____  /____/|____/__|
+//         \/     \/           \/
+// __________                             .__
+// \______   \____________    ____   ____ |  |__
+//  |    |  _/\_  __ \__  \  /    \_/ ___\|  |  \
+//  |    |   \ |  | \// __ \|   |  \  \___|   Y  \
+//  |______  / |__|  (____  /___|  /\___  >___|  /
+//         \/             \/     \/     \/     \/
+
+// SetDefaultBranch updates the default branch
+func SetDefaultBranch(ctx *gitea_context.PrivateContext) {
+	ownerName := ctx.Params(":owner")
+	repoName := ctx.Params(":repo")
+	branch := ctx.Params(":branch")
+	repo, err := models.GetRepositoryByOwnerAndName(ownerName, repoName)
+	if err != nil {
+		log.Error("Failed to get repository: %s/%s Error: %v", ownerName, repoName, err)
+		ctx.JSON(http.StatusInternalServerError, private.Response{
+			Err: fmt.Sprintf("Failed to get repository: %s/%s Error: %v", ownerName, repoName, err),
+		})
+		return
+	}
+	if repo.OwnerName == "" {
+		repo.OwnerName = ownerName
+	}
+
+	repo.DefaultBranch = branch
+	gitRepo, err := git.OpenRepository(repo.RepoPath())
+	if err != nil {
+		ctx.JSON(http.StatusInternalServerError, private.Response{
+			Err: fmt.Sprintf("Failed to get git repository: %s/%s Error: %v", ownerName, repoName, err),
+		})
+		return
+	}
+	if err := gitRepo.SetDefaultBranch(repo.DefaultBranch); err != nil {
+		if !git.IsErrUnsupportedVersion(err) {
+			gitRepo.Close()
+			ctx.JSON(http.StatusInternalServerError, private.Response{
+				Err: fmt.Sprintf("Unable to set default branch on repository: %s/%s Error: %v", ownerName, repoName, err),
+			})
+			return
+		}
+	}
+	gitRepo.Close()
+
+	if err := repo.UpdateDefaultBranch(); err != nil {
+		ctx.JSON(http.StatusInternalServerError, private.Response{
+			Err: fmt.Sprintf("Unable to set default branch on repository: %s/%s Error: %v", ownerName, repoName, err),
+		})
+		return
+	}
+	ctx.PlainText(http.StatusOK, []byte("success"))
+}