ddiff

#!/bin/bash
#
# -+: This indicates that a line was removed in the old diff (before the rebase), but it didn’t appear as a removal in the new diff (after the rebase). So, it’s essentially a change that was removed as part of the rebasing process.
# --: This shows lines that were deleted in both the old and new diffs.
# ++: These are lines that were added in both the old and new diffs.
# +-: This indicates that a line was added in the old diff but removed or changed in the new diff.
#

# Ensure we're in a git repository
if [ ! -d .git ]; then
  echo "This is not a git repository. Exiting."
  exit 1
fi

# Get the current branch and previous branch from git
CURRENT_BRANCH=$(git rev-parse --abbrev-ref HEAD)
PREVIOUS_BRANCH=$(git rev-parse --abbrev-ref @{-1})

echo "Current branch: $CURRENT_BRANCH"
echo "Previous branch: $PREVIOUS_BRANCH"

# Set the main branch as the common branch (adjust if necessary)
MAIN_BRANCH="main"

# Ensure the branches exist
git show-ref --verify --quiet "refs/heads/$CURRENT_BRANCH" || { echo "Branch $CURRENT_BRANCH not found"; exit 1; }
git show-ref --verify --quiet "refs/heads/$PREVIOUS_BRANCH" || { echo "Branch $PREVIOUS_BRANCH not found"; exit 1; }
git show-ref --verify --quiet "refs/heads/$MAIN_BRANCH" || { echo "Main branch $MAIN_BRANCH not found"; exit 1; }

# Get the merge base (common ancestor) for both the current branch and the previous branch relative to main
BASE_COMMIT_PREVIOUS=$(git merge-base $PREVIOUS_BRANCH $MAIN_BRANCH)
BASE_COMMIT_CURRENT=$(git merge-base $CURRENT_BRANCH $MAIN_BRANCH)

# Generate diffs without writing to files
echo "Generating diffs for $PREVIOUS_BRANCH..."
OLD_DIFF=$(git diff $BASE_COMMIT_PREVIOUS..$PREVIOUS_BRANCH)

echo "Generating diffs for $CURRENT_BRANCH..."
NEW_DIFF=$(git diff $BASE_COMMIT_CURRENT..$CURRENT_BRANCH)

# Compare the two diffs
echo "Comparing the diffs between $PREVIOUS_BRANCH and $CURRENT_BRANCH..."
diff -u <(echo "$OLD_DIFF") <(echo "$NEW_DIFF")