Let package git depend on setting but not opposite (#15241)

* Let package git depend on setting but not opposite

* private some package variables

modules/git/lfs.go

@@ -0,0 +1,37 @@
+// 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 git
+
+import (
+	"sync"
+
+	logger "code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
+)
+
+var once sync.Once
+
+// CheckLFSVersion will check lfs version, if not satisfied, then disable it.
+func CheckLFSVersion() {
+	if setting.LFS.StartServer {
+		//Disable LFS client hooks if installed for the current OS user
+		//Needs at least git v2.1.2
+
+		err := LoadGitVersion()
+		if err != nil {
+			logger.Fatal("Error retrieving git version: %v", err)
+		}
+
+		if CheckGitVersionAtLeast("2.1.2") != nil {
+			setting.LFS.StartServer = false
+			logger.Error("LFS server support needs at least Git v2.1.2")
+		} else {
+			once.Do(func() {
+				GlobalCommandArgs = append(GlobalCommandArgs, "-c", "filter.lfs.required=",
+					"-c", "filter.lfs.smudge=", "-c", "filter.lfs.clean=")
+			})
+		}
+	}
+}