Freeze on pull/fetch on Windows with ssh-agent

[ShadowIce]

Describe the bug gitui freezes on fetch at 0% and breaks ssh-agent.

To Reproduce

1. In .bashrc:

eval `ssh-agent -s`
ssh-add ~/.ssh/github
ssh-add ~/.ssh/bitbucket

2. Open git bash in a (large) repository
3. (optional) run git fetch to check that it works
4. Open gitui
5. Try to fetch
6. Wait....
7. Become impatient after a few minutes and hit Ctrl + C (only way to abort this I found)
8. Try to run git fetch in bash. -> fails with "Permission denied (publickey)"

Expected behavior Should fetch within a few seconds.

Context (please complete the following information):

• OS/Distro + Version: Windows 11
• GitUI Version: 0.27.0 2025-01-14 (99f6967) (version from Chocolatey)
• Git for Windows: 2.52.0

Additional context

• 'ssh-add -L' reports "Error connecting to agent: Bad file descriptor" after killing gitui.
• Happens with all github and bitbucket repositories I tried (including gitui) as long as they use ssh and not https.
• I tried to see if ssh-agent would log anything by running ssh-agent -d -s and manually pointing SSH_AUTH_SOCK to the file from the agent in another terminal. For git fetch ssh-agent would output something, but for fetching in gitui it's completely silent.
• I did not try to push but I would assume it has similar issues.
• If I wait long enough on a fetch the progress dialog will be gone. ssh-agent will still be broken though.
• If I wait long enough on a pull I'm getting this error: "git error:error authenticating: agent list id failed; class=Ssh (23)"