How to fix fatal: error in object: unshallow in Git

Before attempting to unshallow, check if your repository is actually shallow:

git rev-parse --is-shallow-repository

If this returns false, your repository is already complete and doesn't need unshallowing. This is the most common cause of the error.

For Git versions before 2.14, check for the existence of the shallow file:

ls -la .git/shallow

If the file doesn't exist, you have a full clone.

If you get "fatal: error in object: unshallow", the repository's object database may be corrupted. Run a repack to rebuild it:

git repack -d

For more thorough repair:

git repack -aldf

After repacking, try unshallowing again:

git fetch --unshallow

Instead of --unshallow, specify a very large depth value (effectively infinite):

git fetch --depth=2147483647

This is the maximum signed 32-bit integer value and tells Git to fetch all available history. This approach can be more reliable than --unshallow in some scenarios.

After successfully unshallowing, you may still only have one branch. To fetch all remote branches, update your remote configuration:

git config remote.origin.fetch "+refs/heads/*:refs/remotes/origin/*"
git fetch origin

Or for a one-time fetch of all branches:

git fetch origin '+refs/heads/*:refs/remotes/origin/*'

If this error occurs in CI/CD pipelines, configure your system to perform full clones from the start.

GitHub Actions:

- uses: actions/checkout@v4
  with:
    fetch-depth: 0  # Full clone

GitLab CI:

variables:
  GIT_DEPTH: 0  # Or use a large number like 1000

Azure DevOps:

- checkout: self
  fetchDepth: 0

CircleCI (.circleci/config.yml):

checkout:
  post:
    - git fetch --unshallow || true

The || true ensures the build continues even if unshallow fails because the repo is already complete.

Azure DevOps may have issues with branches/tags that differ only in case (e.g., "Release/1.0.0" vs "release/1.0.0"). Remove conflicting branches:

# List all branches
git branch -a

# Delete conflicting remote branches (adjust as needed)
git push origin --delete Task/branch-name

# Keep only lowercase versions

This resolves issues introduced by Azure DevOps case sensitivity changes.

For very large repositories where --unshallow times out, deepen the clone incrementally:

git fetch --depth=100
git fetch --depth=500
git fetch --depth=1000
git fetch --unshallow

Each step adds more history. If a step fails, the existing clone remains intact and you can retry.

If the shallow repository is irreparably damaged, perform a fresh full clone:

# Backup any local changes
git diff > local-changes.patch
git diff --staged > staged-changes.patch

# Clone fresh without depth restriction
cd ..
rm -rf old-repo
git clone https://github.com/user/repo.git

# Apply backed-up changes if needed
cd repo
git apply ../local-changes.patch

Use --no-single-branch if you need all branches from the start:

git clone --no-single-branch https://github.com/user/repo.git