git commit stopped working - Error building trees

This error means that you have a file with hash 13da9eeff5a9150cf2135aaed4d2e337f97b8114, and this hash is not present in .git/objects/../, or it's empty. When this error occurred, I only had this hash in the error, without the file path. Then I tried to do git gc --auto and git reset --hard. After one of these commands (these commands did not fix my problem), I got the path of the file that triggers the error.

You just need to generate the object hash:

git hash-object -w spec/routing/splits_routing_spec.rb

For more information see documentation. In the documentation, there is an additional way of repairing this error.

P.S. This was the only way that was helpful for me.

You might have a corrupted object in your git repository.

If you have a remote, or other clones of this repository, you could grab from there the problematic file and just replace it on your local repo.

The file you want would be in:

/repo/.git/objects/13/da9eeff5a9150cf2135aaed4d2e337f97b8114