fix: Listening on abstract domain sockets (#7020)

When passed a socket name that starts with @, go will listen on an
abstract unix domain socket. Forgejo breaks this by assuming the socket
name is a file path and normalizing it to an absolute path.

This small commit prevents treating the socket name as a filesystem path
if it starts with @.

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/7020
Reviewed-by: Gusted <gusted@noreply.codeberg.org>
Co-authored-by: Mewp <codeberg.org@mewp.pl>
Co-committed-by: Mewp <codeberg.org@mewp.pl>

modules/setting/server.go

@@ -265,7 +265,7 @@ func loadServerFrom(rootCfg ConfigProvider) {
 		}
 
 		UnixSocketPermission = uint32(UnixSocketPermissionParsed)
-		if !filepath.IsAbs(HTTPAddr) {
+		if HTTPAddr[0] != '@' && !filepath.IsAbs(HTTPAddr) {
 			HTTPAddr = filepath.Join(AppWorkPath, HTTPAddr)
 		}
 	}