How to fix fatal: unable to read tree object in treeless clone in Git

# Check the remote URL
git remote -v

# Test connectivity to the remote
git ls-remote origin

# Try to fetch explicitly
git fetch origin

# Check proxy settings
git config --global --get http.proxy
git config --global --get https.proxy

# Test with verbose output
GIT_TRACE=1 GIT_CURL_VERBOSE=1 git fetch origin

# Check current partial clone configuration
git config --get remote.origin.partialclonefilter

# Remove the filter setting
git config --unset remote.origin.partialclonefilter

# Fetch all objects with --refetch
git fetch --refetch

# Remove the promisor marking (indicates objects may be missing)
git config --unset remote.origin.promisor

# Verify the conversion
git fsck

# If the above doesn't work, do a fresh clone
cd ..
mv my-repo my-repo-backup
git clone https://github.com/user/repo.git my-repo
cd my-repo

# Copy any local changes from backup if needed

# Blobless clone - downloads all commits and trees, but not file contents
git clone --filter=blob:none https://github.com/user/repo.git

# This is better because:
# - git log -- <path> works without downloading extra objects
# - Only file contents (blobs) are fetched on demand
# - Much more compatible with normal Git workflows

# Unfortunately, you cannot directly convert between filter types
# You need to re-clone with the blobless filter

cd ..
git clone --filter=blob:none https://github.com/user/repo.git my-repo-new

# Prevent fetch from downloading trees for submodule changes
git config fetch.recurseSubmodules false

# Now fetch won't trigger tree downloads for submodule detection
git fetch origin

# When initially cloning, don't recurse into submodules
git clone --filter=tree:0 --no-recurse-submodules https://github.com/user/repo.git

# Initialize submodules separately if needed
git submodule update --init --depth 1

# GitHub Actions example
- uses: actions/checkout@v4
  with:
    filter: blob:none  # Use blobless, not treeless
    submodules: false  # Handle submodules separately

- uses: actions/checkout@v4
  with:
    # Option 1: Shallow clone (usually sufficient for builds)
    fetch-depth: 1

    # Option 2: Blobless clone (if you need history)
    # filter: blob:none

variables:
  # Use shallow clone instead of treeless
  GIT_DEPTH: 1
  # Or for blobless:
  # GIT_STRATEGY: clone
  # GIT_CLONE_PATH: $CI_BUILDS_DIR/$CI_PROJECT_PATH

script:
  - git clone --filter=blob:none --depth 1 $CI_REPOSITORY_URL .

- checkout:
    # CircleCI doesn't support treeless clones well
    # Use shallow clone instead
    depth: 1

checkout([
    $class: 'GitSCM',
    branches: [[name: '*/main']],
    extensions: [[$class: 'CloneOption', shallow: true, depth: 1]],
    userRemoteConfigs: [[url: 'https://github.com/user/repo.git']]
])

# Run fsck to identify issues
git fsck --full

# Check promisor remote configuration
git config --get remote.origin.promisor
git config --get remote.origin.partialclonefilter

# If promisor is incorrectly set
git config remote.origin.promisor true
git config remote.origin.partialclonefilter tree:0

# Try fetching again
git fetch origin

# Attempt to fetch the specific missing tree (if you know the hash)
git fetch-pack --thin origin <tree-hash>

# Or fetch everything from the remote
git fetch --all --prune

# Backup any local work
git stash
git format-patch origin/main --stdout > my-changes.patch

# Fresh clone
cd ..
rm -rf my-repo
git clone https://github.com/user/repo.git my-repo

# Apply saved changes
cd my-repo
git apply ../my-repo-backup/my-changes.patch