Pre-Commit Hook: Handle Deleted Files Gracefully

Pre-Commit Hook: Handle Deleted Files Gracefully

Problem Statement

The pre-commit hook (core-web/.husky/pre-commit) fails when attempting to restore files that have been deleted and staged for commit. This causes the entire commit process to fail with an error:

fatal: pathspec 'core-web/libs/sdk/analytics/src/lib/core/shared/dot-content-analytics.activity-tracker.spec.ts' did not match any files

Root Cause

The hook attempts to restore files using git restore in three locations:

1. Line ~292: When restoring unmatched files that were modified by linting/formatting
2. Line ~531: When backing up untracked files during the restore process
3. Line ~542: When restoring untracked files after processing

When a file is deleted (marked with D in git status) and staged, git restore fails because the file no longer exists in the working directory. The hook doesn't check if a file is deleted before attempting to restore it.

Impact

• Developer Experience: Commits fail unexpectedly when files are deleted as part of refactoring or cleanup
• Workflow Disruption: Developers must bypass the hook with --no-verify to commit, which defeats the purpose of pre-commit checks
• Error Messages: The error message is not clear about what's happening, making it difficult to diagnose

Example Scenario

When refactoring code and moving/renaming files:

# File is deleted and staged
git status
# D  core-web/libs/sdk/analytics/src/lib/core/shared/dot-content-analytics.activity-tracker.spec.ts

# Attempting to commit triggers pre-commit hook
git commit -m "Refactor: Move analytics tracker to new location"
# ❌ fatal: pathspec '...' did not match any files

Proposed Solution

Update the pre-commit hook to detect deleted files before attempting to restore them. The fix involves:

1. Check for deleted files first: Before calling git restore, check if the file is marked as deleted (D) in staged changes
2. Skip restore for deleted files: If a file is deleted, skip the restore operation and log an informational message
3. Handle non-existent files gracefully: If a file doesn't exist in the git index, skip restore operations

Implementation Details

Location 1: Unmatched Files Restoration (Line ~288-303)

Current Code:

for file in "${unmatched_files[@]}"; do
    printf "    %s\n" "${file}"
    cd "$root_dir" || exit 1
    git restore "${file}"  # ❌ Fails for deleted files
    cd "${root_dir}/core-web" || exit 1
done

Fixed Code:

for file in "${unmatched_files[@]}"; do
    printf "    %s\n" "${file}"
    cd "$root_dir" || exit 1
    # Check if file is deleted (D) in staged changes first
    if git diff --cached --name-status | grep -q "^D[[:space:]].*${file}$"; then
        # File is deleted, skip restore
        print_color "$BLUE" "    ℹ️  Skipping restore for deleted file: ${file}"
    elif git ls-files --error-unmatch "${file}" >/dev/null 2>&1; then
        # File exists in git index, safe to restore
        git restore "${file}" 2>/dev/null || true
    else
        # File doesn't exist, skip restore
        print_color "$BLUE" "    ℹ️  Skipping restore for non-existent file: ${file}"
    fi
    cd "${root_dir}/core-web" || exit 1
done

Location 2: Untracked Files Backup (Line ~524-534)

Current Code:

for file in $untracked_files; do
    if echo "${staged_files}" | grep -q "^${file}$"; then
        mkdir -p "${temp_dir}/$(dirname "${file}")"
        cp "${root_dir}/${file}" "${temp_dir}/${file}"  # ❌ Fails if file doesn't exist
        print_color "$BLUE" "💾 Backing up ${file}"
        cd "$root_dir" || exit 1
        git restore "${file}"  # ❌ Fails for deleted files
        cd "${root_dir}/core-web" || exit 1
    fi
done

Fixed Code:

for file in $untracked_files; do
    if echo "${staged_files}" | grep -q "^${file}$"; then
        # Check if file exists before trying to backup
        if [ -f "${root_dir}/${file}" ]; then
            mkdir -p "${temp_dir}/$(dirname "${file}")"
            cp "${root_dir}/${file}" "${temp_dir}/${file}"
            print_color "$BLUE" "💾 Backing up ${file}"
            cd "$root_dir" || exit 1
            git restore "${file}" 2>/dev/null || true
            cd "${root_dir}/core-web" || exit 1
        else
            print_color "$BLUE" "ℹ️  Skipping backup for non-existent file: ${file}"
        fi
    fi
done

Location 3: Second Untracked Files Restore (Line ~539-545)

Current Code:

for file in $untracked_files; do
    if echo "${staged_files}" | grep -q "^${file}$"; then
        cd "$root_dir" || exit 1
        git restore "${file}"  # ❌ Fails for deleted files
        cd "${root_dir}/core-web" || exit 1
    fi
done

Fixed Code:

for file in $untracked_files; do
    if echo "${staged_files}" | grep -q "^${file}$"; then
        # Only restore if file exists in git index
        if git ls-files --error-unmatch "${file}" >/dev/null 2>&1; then
            cd "$root_dir" || exit 1
            git restore "${file}" 2>/dev/null || true
            cd "${root_dir}/core-web" || exit 1
        fi
    fi
done

Benefits

1. Robust Error Handling: The hook no longer fails when files are deleted
2. Better Developer Experience: Developers can commit refactoring changes without bypassing hooks
3. Clear Feedback: Informational messages explain why certain operations are skipped
4. Maintains Functionality: All existing functionality remains intact for non-deleted files

Testing Scenarios

To verify the fix works correctly, test with:

1. Deleted file in staged changes: Stage a file deletion and attempt to commit
2. Mixed changes: Stage both file deletions and modifications together
3. Renamed files: Stage file renames (which appear as delete + add)
4. Non-existent files: Handle edge cases where files are referenced but don't exist

Acceptance Criteria

• Pre-commit hook successfully handles deleted files without errors
• Pre-commit hook successfully handles mixed changes (deletions + modifications)
• Pre-commit hook successfully handles file renames
• Pre-commit hook maintains all existing functionality for non-deleted files
• Informational messages are displayed when skipping restore operations
• No regression in existing pre-commit hook behavior

Related Files

• core-web/.husky/pre-commit - The pre-commit hook script that needs updating

Priority

Medium - This is a quality-of-life improvement that prevents workflow disruption but doesn't block critical functionality. Developers can currently work around it using --no-verify, but fixing it improves the overall developer experience.

Notes

• This fix was identified during a refactoring session where multiple files were being moved/renamed
• The fix is backward compatible and doesn't change the behavior for non-deleted files
• The solution uses standard git commands and bash patterns already present in the hook