A script to reproduce `git fsck` failures on `.gitmodules` history

git-problem-repro.sh

#!/usr/bin/env -S bash -euo pipefail

# Reproduce git fsck problem

DIR=$(mktemp -d)
trap 'cd /; rm -rf "$DIR"' EXIT

cd "$DIR"

git init
git config commit.gpgsign false

git submodule add https://github.com/git/book.git-scm.com.git # Can be any repo
git commit -am "Add submodule"

# fsck will succeed
git fsck

sed -i~ 's#github.com/#github.com:#' .gitmodules
git commit -am "Mess up submodule url"

git revert --no-edit @

# Predict hash of problem blob
echo -n "Problem blob: "
echo @^:.gitmodules | git cat-file --batch-check='%(objectname)'

# fsck will fail on problem blob
git fsck