Script to merge branches in a way that keeps the repository history nice and clean.

git-clean-merge

#!/bin/bash

# Use the current branch as the source
SOURCE_BRANCH=`git rev-parse --abbrev-ref HEAD`
TARGET_BRANCH=${1:-master}

if [ "$SOURCE_BRANCH" = "" ]; then
    # Something went wrong, but git probably already said what, just exit.
    exit 1;
fi

if [ "`git rev-parse $TARGET_BRANCH 2>/dev/null`" = "$TARGET_BRANCH" ]; then
    echo "Target branch '$TARGET_BRANCH' does not exist."
    exit 1
fi

if [ "$SOURCE_BRANCH" = "$TARGET_BRANCH" ]; then
    echo "On target branch '$TARGET_BRANCH', nothing to merge."
    exit 1
fi

if [ ! -z "`git status -uno -s`" ]; then
    echo "Working tree not clean, not merging."
    exit 1
fi 
    
if [ "`git merge-base $TARGET_BRANCH $SOURCE_BRANCH`" != "`git rev-parse $TARGET_BRANCH`" ]; then
    echo "Branch can not be merged cleanly.  Rebase '$SOURCE_BRANCH' onto '$TARGET_BRANCH' first."
    exit 1
fi

echo "Trying to merge '$SOURCE_BRANCH' cleanly into '$TARGET_BRANCH'" && \
    git checkout $TARGET_BRANCH && \
    git merge --no-ff $SOURCE_BRANCH && \
    git branch -d $SOURCE_BRANCH && \
    echo "Branch '$SOURCE_BRANCH' succesfully merged into '$TARGET_BRANCH'"

# TODO:
# - [ ] Optional sync before merging (see older version)
# - [ ] Option to initiate rebasing if needed
# - [ ] Look up pull request (use git ls-remote)
# - [ ] Rewrite message when pull request (see github)