Compare branches in a Git repository, detect merge conflicts, and display detailed outputs with options for verbosity and branch customization.

git_detect_conflict.sh

#!/bin/bash

# Default values
base_branch=""
compare_branch=""
verbose=false
compare_all=false

# Help documentation
usage() {
    echo "Usage: $0 [OPTIONS]"
    echo ""
    echo "Options:"
    echo "  --base, -b       Specify the base branch to compare against (default: origin/develop, origin/main)"
    echo "  --compare, -c    Specify the branch to compare with the base branch (default: current branch)"
    echo "  --all, -a        Compare the base branch against all active branches"
    echo "  --verbose, -v    Show detailed output including conflicting file paths"
    echo "  --help, -h       Display this help message"
    echo ""
    echo "Description:"
    echo "This script compares the number of commits and detects conflicts between a base branch"
    echo "and other branches in the current Git repository."
    echo ""
    echo "Examples:"
    echo "  Compare current branch with develop/main: $0"
    echo "  Compare base branch with all active branches: $0 -a"
    echo "  Compare specific branches with detailed output: $0 -b develop -c feature-branch -v"
    echo ""
    exit 0
}

# Parse arguments
while [[ "$#" -gt 0 ]]; do
    case $1 in
    --base | -b)
        base_branch="$2"
        shift 2
        ;;
    --compare | -c)
        compare_branch="$2"
        shift 2
        ;;
    --all | -a)
        compare_all=true
        shift
        ;;
    --verbose | -v)
        verbose=true
        shift
        ;;
    --help | -h)
        usage
        ;;
    *)
        echo "Unknown option: $1"
        usage
        ;;
    esac
done

# Check if we're in a Git repository
if ! git rev-parse --is-inside-work-tree >/dev/null 2>&1; then
    echo "Error: Not inside a Git repository." >&2
    exit 1
fi

# Determine the base branch if not explicitly set
if [[ -z "$base_branch" ]]; then
    echo "Determining the base branch..."
    if git show-ref --verify --quiet refs/remotes/origin/develop; then
        base_branch="origin/develop"
    elif git show-ref --verify --quiet refs/remotes/origin/main; then
        base_branch="origin/main"
    else
        echo "Error: No default base branch found. This repository doesn't have 'origin/develop' or 'origin/main'."
        echo "Please specify a base branch explicitly using --base or -b."
        exit 1
    fi
fi

# Get the current branch if compare branch is not provided and not using --all
if [[ -z "$compare_branch" && "$compare_all" == false ]]; then
    compare_branch=$(git rev-parse --abbrev-ref HEAD)
fi

# Ensure you have the latest changes before comparing
echo "Fetching latest changes..."
git fetch --all

# Function to check conflicts between branches
check_conflicts() {
    local base=$1
    local compare=$2

    echo "Comparing $base to $compare..."
    behind_ahead=$(git rev-list --left-right --count "$base...$compare" 2>/dev/null)
    if [[ $? -ne 0 ]]; then
        echo "Error: Failed to compare $base and $compare. Ensure both branches exist."
        return
    fi

    behind=$(echo "$behind_ahead" | awk '{print $1}')
    ahead=$(echo "$behind_ahead" | awk '{print $2}')
    echo "Behind $base by: $behind commits"
    echo "Ahead of $base by: $ahead commits"

    # Check for conflicts
    conflicts=$(git merge-tree $(git merge-base $base $compare) $base $compare | grep '^<<<<<<< ')
    if [[ -n "$conflicts" ]]; then
        echo "Conflict Detected on $compare in $(echo "$conflicts" | wc -l) files"
        if [[ "$verbose" == true ]]; then
            echo "Conflicts:"
            echo "$conflicts"
        fi
    else
        echo "No conflicts detected on $compare."
    fi
}

# Compare all branches if --all is specified
if [[ "$compare_all" == true ]]; then
    branches=$(git branch -r | grep -v "$base_branch" | grep -v "HEAD")
    total_branches=$(echo "$branches" | wc -l) # Count the total branches
    count=0

    for branch in $branches; do
        ((count++))
        check_conflicts "$base_branch" "$branch"

        # Add a divider only if it's not the last branch
        if [[ $count -lt $total_branches ]]; then
            echo
            echo "----------------------------------------"
            echo
        fi
    done
else
    # Compare specified or default branches
    check_conflicts "$base_branch" "$compare_branch"
fi