Update

modules/structs/fork.go

@@ -13,7 +13,8 @@ type CreateForkOption struct {
 
 // SyncForkInfo information about syncing a fork
 type SyncForkInfo struct {
-	Allowed    bool   `json:"allowed"`
-	ForkCommit string `json:"fork_commit"`
-	BaseCommit string `json:"base_commit"`
+	Allowed       bool   `json:"allowed"`
+	ForkCommit    string `json:"fork_commit"`
+	BaseCommit    string `json:"base_commit"`
+	CommitsBehind int    `json:"commits_behind"`
 }

options/locale/locale_en-US.ini

@@ -1145,7 +1145,8 @@ archive.title_date = This repository has been archived on %s. You can view files
 archive.issue.nocomment = This repo is archived. You cannot comment on issues.
 archive.pull.nocomment = This repo is archived. You cannot comment on pull requests.
 
-sync_fork.text = This branch is behind %s
+sync_fork.text_1 = This branch is 1 commit behind %s
+sync_fork.text_n = This branch is %d commits behind %s
 sync_fork.button = Sync
 
 form.reach_limit_of_creation_1 = The owner has already reached the limit of %d repository.

routers/api/v1/repo/sync_fork.go

@@ -4,7 +4,7 @@ import (
 	"net/http"
 
 	git_model "code.gitea.io/gitea/models/git"
-	"code.gitea.io/gitea/modules/context"
+	"code.gitea.io/gitea/services/context"
 	repo_service "code.gitea.io/gitea/services/repository"
 )
 

routers/web/repo/view.go

@@ -1146,6 +1146,7 @@ PostRecentBranchCheck:
 
 		if syncForkInfo.Allowed {
 			ctx.Data["CanSyncFork"] = true
+			ctx.Data["ForkCommitsBehind"] = syncForkInfo.CommitsBehind
 			ctx.Data["SyncForkLink"] = fmt.Sprintf("%s/sync_fork/%s", ctx.Repo.RepoLink, util.PathEscapeSegments(ctx.Repo.BranchName))
 			ctx.Data["BaseBranchLink"] = fmt.Sprintf("%s/src/branch/%s", ctx.Repo.Repository.BaseRepo.HTMLURL(), util.PathEscapeSegments(ctx.Repo.BranchName))
 		}

services/repository/sync_fork.go

@@ -27,30 +27,7 @@ func SyncFork(ctx context.Context, doer *user_model.User, repo *repo_model.Repos
 		return err
 	}
 
-	repo.RepoPath()
-
-	err = git.NewCommand(ctx, "fetch", "--force").AddDynamicArguments(repo.BaseRepo.RepoPath(), fmt.Sprintf("%s:%s", branch, branch)).Run(&git.RunOpts{Dir: repo.RepoPath()})
-	if err != nil {
-		return err
-	}
-
-	gitRepo, err := git.OpenRepository(ctx, repo.RepoPath())
-	if err != nil {
-		return err
-	}
-	defer gitRepo.Close()
-
-	forkBranch, err := gitRepo.GetBranch(branch)
-	if err != nil {
-		return err
-	}
-
-	commit, err := forkBranch.GetCommit()
-	if err != nil {
-		return err
-	}
-
-	_, err = git_model.UpdateBranch(ctx, repo.ID, doer.ID, branch, commit)
+	err = git.NewCommand(ctx, "fetch").AddDynamicArguments(repo.BaseRepo.RepoPath(), fmt.Sprintf("%s:%s", branch, branch)).Run(&git.RunOpts{Dir: repo.RepoPath()})
 	if err != nil {
 		return err
 	}
@@ -123,7 +100,17 @@ func GetSyncForkInfo(ctx context.Context, repo *repo_model.Repository, branch st
 		return nil, err
 	}
 
-	info.Allowed = slices.Contains(branchList, branch)
+	if !slices.Contains(branchList, branch) {
+		return info, nil
+	}
+
+	diff, err := git.GetDivergingCommits(ctx, repo.BaseRepo.RepoPath(), baseBranch.CommitID, forkBranch.CommitID)
+	if err != nil {
+		return nil, err
+	}
+
+	info.Allowed = true
+	info.CommitsBehind = diff.Behind
 
 	return info, nil
 }

templates/repo/home.tmpl

@@ -163,11 +163,15 @@
 		</div>
 
 		{{if .CanSyncFork}}
-			<div class="ui positive message gt-df gt-ac">
-				<div class="gt-f1">
-					{{ctx.Locale.Tr "repo.sync_fork.text" (printf "<a href='%s'>%s:%s</a>" .BaseBranchLink .Repository.BaseRepo.FullName (.BranchName|Escape) | Safe)}}
+			<div class="ui positive message tw-flex tw-items-center">
+				<div class="tw-flex-1">
+					{{if eq .ForkCommitsBehind 1}}
+						{{ctx.Locale.Tr "repo.sync_fork.text_1" (printf "<a href='%s'>%s:%s</a>" .BaseBranchLink .Repository.BaseRepo.FullName .BranchName | SafeHTML)}}
+					{{else}}
+						{{ctx.Locale.Tr "repo.sync_fork.text_n" .ForkCommitsBehind (printf "<a href='%s'>%s:%s</a>" .BaseBranchLink .Repository.BaseRepo.FullName .BranchName | SafeHTML)}}
+					{{end}}
 				</div>
-				<a role="button" class="ui compact positive button gt-m-0" href="{{.SyncForkLink}}">
+				<a role="button" class="ui compact positive button tw-m-0" href="{{.SyncForkLink}}">
 					{{ctx.Locale.Tr "repo.sync_fork.button"}}
 				</a>
 			</div>