Git Author Rewrite

reauthor.sh

#!/bin/bash
# ----------------------------------------------------------------------
# Author: JerodG <https://github.com/jerodg>
# File: reauthor.sh
# 
# Purpose: Updates git commit history in multiple repositories by:
# - Changing author and committer details 
# - Adding GPG signing information
# - Rebasing and re-signing all commits
#
# This script processes all git repositories in the current location
# and requires git-filter-repo to be installed.
# ----------------------------------------------------------------------

# Configuration
GIT_AUTHOR_NAME=""
GIT_AUTHOR_EMAIL=""
GIT_COMMITTER_NAME=""
GIT_COMMITTER_EMAIL=""
GIT_SIGNING_KEY=""

# Check that configuration variables have been set
if [ -z "$GIT_AUTHOR_NAME" ] || [ -z "$GIT_AUTHOR_EMAIL" ] || [ -z "$GIT_COMMITTER_NAME" ] || [ -z "$GIT_COMMITTER_EMAIL" ] || [ -z "$GIT_SIGNING_KEY" ]; then
    echo "Please configure the GIT_AUTHOR_NAME, GIT_AUTHOR_EMAIL, GIT_COMMITTER_NAME, GIT_COMMITTER_EMAIL, and GIT_SIGNING_KEY variables before running this script."
    exit 1
fi

# Color codes for terminal output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[0;33m'
BLUE='\033[0;34m'
NC='\033[0m' # No Color

# Log messages with appropriate colors
log_info() {
    echo -e "${BLUE}[INFO]${NC} $1"
}

log_success() {
    echo -e "${GREEN}[SUCCESS]${NC} $1"
}

log_warning() {
    echo -e "${YELLOW}[WARNING]${NC} $1"
}

log_error() {
    echo -e "${RED}[ERROR]${NC} $1"
}

# Error handling function
handle_error() {
    log_error "$1"
    exit "${2:-1}" # Default to exit code 1 if not specified
}

# Verify git-filter-repo availability before proceeding
# Exit early if the required tool isn't available
if ! command -v git-filter-repo &> /dev/null
then
    handle_error "git-filter-repo could not be found, please install it first." 2
fi

# Find all directories that are git repositories
folders=$(find . -maxdepth 1 -type d -name "zs.*" -exec test -e "{}/.git" ';' -print)

# Validate that at least one matching directory was found
# Exit early if no directories match the pattern
if [ -z "$folders" ]; then
    handle_error "No git repositories found." 3
fi

# Count the number of folders for progress tracking
total_folders=$(echo "$folders" | wc -l)
current_folder=0

# Process each matching directory
for folder in $folders; do
    current_folder=$((current_folder + 1))
    log_info "Processing folder: $folder ($current_folder of $total_folders)"

    # Navigate to target repository
    cd "$folder" || handle_error "Failed to enter directory: $folder" 4

    # Count total commits for progress reporting
    total_commits=$(git rev-list --count --all 2>/dev/null)
    if [ $? -ne 0 ]; then
        log_warning "Could not count commits in $folder. Continuing anyway."
        total_commits="unknown"
    else
        log_info "Found $total_commits commits to process"
    fi

    # Modify the commit history:
    # - Updates author and committer information
    # - Sets GPG signing key
    # - Preserves original commit timestamps
    log_info "Rewriting commit history with new identity..."
    if ! git filter-repo --force \
    --commit-callback '
                commit.author_name = b"'"$GIT_AUTHOR_NAME"'"
                commit.author_email = b"'"$GIT_AUTHOR_EMAIL"'"
                commit.committer_name = b"'"$GIT_COMMITTER_NAME"'"
                commit.committer_email = b"'"$GIT_COMMITTER_EMAIL"'"
                commit.signing_key = b"'"$GIT_SIGNING_KEY"'"
                commit.committer_date = commit.committer_date
                commit.author_date = commit.author_date
        ' > /dev/null 2>&1; then
        log_error "Failed to modify commit history in $folder. Continuing with next repository."
        cd .. || handle_error "Failed to return to parent directory" 5
        continue
    fi

    # Re-sign all commits with the configured GPG key
    log_info "Re-signing all commits with GPG key..."
    if ! git rebase --exec 'git commit --amend --no-edit -n -S' --root; then
        log_error "Failed to re-sign commits in $folder. Manual intervention may be required."
        # Creating a recovery script for this repository
        echo "#!/bin/bash" > "../recover_$folder.sh"
        echo "cd $folder" >> "../recover_$folder.sh"
        echo "git rebase --abort" >> "../recover_$folder.sh"
        chmod +x "../recover_$folder.sh"
        log_warning "Created recovery script: recover_$folder.sh"
    else
        log_success "Successfully processed $folder"
    fi

    # Return to the parent directory before processing the next repository
    cd .. || handle_error "Failed to return to parent directory" 5
done

# Final status report
if [ $current_folder -eq $total_folders ]; then
    log_success "All $total_folders repositories have been processed."
else
    log_warning "Processed $current_folder out of $total_folders repositories."
fi

exit 0