Subject: Re: Update to Git 2.34.0 breaks application

From: Phillip Wood <[email-masked]>
Date: Mon, 22 Nov 2021 21:43:51 +0000

Hi Alex

Thanks for the report

On 22/11/2021 08:42, Alexander Veit wrote:
> After an update from Git 2.25.1 to 2.34.0 the Java application that uses 
> the Eclipse JGit library freezes.
> 
> Strace suggests that the JVM receives a SIGTTOU from the child process 
> "git config --system --edit" created with java.lang.ProcessBuilder.
> 
> Upstream[1] has identified 3d411afa[2] as the possible commit that 
> introduced the problem.
> 
> The problem does not occur on all Linux systems.

I think the problem is possibly that git is calling tcsetattr() from a 
background process group[1]. A possible fix would be to call tcgetpgrp() 
after opening /dev/tty to see if git is in the foreground process group.

Best Wishes

Phillip

[1] https://www.man7.org/linux/man-pages/man3/tcsetattr.3p.html

> -Alex
> 
> Environment:
> OS: Linux Mint 20
> Kernel: 5.4.0-90-generic
> Git 2.34.0 from http://ppa.launchpad.net/git-core/ppa/ubuntu
> Java: OpenJDK 64-Bit Server VM AdoptOpenJDK (build 11.0.10+9, mixed mode)
> 
> 
> Ref.:
> [1] https://bugs.eclipse.org/bugs/show_bug.cgi?id=577358
> [2] 
> https://github.com/git/git/commit/3d411afabc9a96f41d47c07d6af6edda3d29ec92#diff-01b59b6a71e42b9c1251ffbf76a1119b965be087a78538e80e01f9239c8e5880 
>