🐞 Bug `run_command` - Ruby `IO.popen` memory leak

[Rikj000]

Issue Description

There appears to be a memory leak in svn2git's run_command function,
I assume in IO.popen.

This memory leak leads to eating up all the RAM + Swap memory (128Gb + 64Gb on my system) during large conversions,
which will eventually crash the svn2git process once RAM is full.

In below btop screenshots you can see that:

• This issue occurs while svn2git is running git svn fetch (which is called through run_command)
• git svn fetch does not experience a memory leak, since it's memory usage stays low
• svn2git does experience a memory leak, since it's memory usage keeps on growing

Click to Expand/Collapse the "Screenshots"

0h40min - 33.4Gb

33.4Gb RAM + 0Gb Swap

1h01min - 51.6Gb

56.1Gb RAM + 0Gb Swap

2h11min - 120Gb

56.1Gb RAM + 63.9Gb Swap

3h00min - 159.6Gb

95.7Gb RAM + 63.9Gb Swap

Work Around

1. Either wait for svn2git to crash when out of memory,
   or manually force stop it with x2 CTRL + C
   (and also docker container ls + docker stop <container-id> when using Rikj000/Ruby-SVN2Git-Docker)
2. Process continues upon restart, however:
   • In case of crash upon restart, fix by:
     • Open the .git/config file in the output Git repo
     • Delete all branches + tags entries within
     • Delete the .git/svn/refs/remotes/svn/trunk/index.lock file in the output Git repo, if it exists
   • Disk space cleanup before restart:
     • Open the .git/objects/pack/ directory in the output Git repo
     • Delete all (usually very large) tmp_pack_...... files within
     • See: https://old.reddit.com/r/git/comments/324ejz/can_i_safely_delete_tmp_pack_files_in/