Cannot commit error: Load key "path": invalid format? - github

Question

When I tried to commit my work I've this message :
error: Load key "/var/folders/97/8chxzhxs3n79g9b95510jwwr0000gn/T//.git_signing_key_tmp2JvaYk": invalid format?
fatal: failed to write commit object
Please can help me, I can't commit anything.
I see many topics about this with ssh-add and ss-agent but none works for my case...
I've tried to regenerate my ssh key with ssh-keygen. I've remove my id_rsa and id_rsa.pub to regenerate them.
Question : the message is -> error: Load key "/var/folders/97/8chxzhxs3n79g9b95510jwwr0000gn/T//.git_signing_key_tmp2JvaYk": invalid format?
But my key are located in ~/.ssh/id_rsa... I don't understand.

Answer 1

If your private key is passphrase-protected (meaning, encrypted), you would need to add your SSH key to an SSH agent.
Check also "Signing Git Commits with Your SSH Key" from Caleb Hearth.
Only then a git commit -S (signing the commit) would work.
Or you might have told Git about your SSH key:
git config --global gpg.format ssh
git config --global user.signingkey 'key::ssh-ed25519 AAAAC3(...) user#example.com'
Note that, with Git 2.40 (Q1 2023), the error message is improved when private key is not loaded in the SSH agent in the codepath to sign with an SSH key.
See commit dce7b31 (25 Jan 2023) by Adam Szkoda (adaszko).
(Merged by Junio C Hamano -- gitster -- in commit c7757b2, 03 Feb 2023)
ssh signing: better error message when key not in agent
Signed-off-by: Adam Szkoda
When signing a commit with a SSH key, with the private key missing from ssh-agent, a confusing error message is produced:
error: Load key
"/var/folders/t5/cscwwl_n3n1_8_5j_00x_3t40000gn/T//.git_signing_key_tmpkArSj7":
invalid format? fatal: failed to write commit object
The temporary file .git_signing_key_tmpkArSj7 created by Git contains a valid public key.
The error message comes from ssh-keygen -Y sign' and is caused by a fallback mechanism in ssh-keygenwhereby it tries to interpret.git_signing_key_tmpkArSj7` as a private key if it can't find in the agent.
A fix is scheduled to be released in OpenSSH 9.1.
All that needs to be done is to pass an additional backward-compatible option -U to 'ssh-keygen -Y sign' call.
With '-U', ssh-keygen always interprets the file as public key and expects to find the private key in the agent.
As a result, when the private key is missing from the agent, a more accurate error message gets produced:
error: Couldn't find key in agent