post-checkout git hook to stash deps and _build

post-checkout

#!/bin/sh
# Set this to a list of space-separated paths to files/directories,
# which will be stashed away, when the current branch is changed
ARTIFACT_PATHS="deps _build"
# Set this to a directory where you would like the build artifacts of
# other branches to be stashed
ARTIFACT_STASH_PATH=".artifacts-stash"
PREVIOUS_HEAD="$1"
CURRENT_HEAD="$2"
IS_BRANCH_CHECKOUT="$3"
if [ "$IS_BRANCH_CHECKOUT" = "0" ] ; then
    # This was a "file" checkout, not a branch switch.
    exit 0
fi
if [ "$PREVIOUS_HEAD" = "$CURRENT_HEAD" ]; then
    # Branch wasn't actually changed. Nothing to do.
    exit 0
fi
PREVIOUS_HEAD_SHORT=$(echo $PREVIOUS_HEAD | head -c8)
CURRENT_HEAD_SHORT=$(echo $CURRENT_HEAD | head -c8)
PREVIOUS_STASH_PATH="$ARTIFACT_STASH_PATH/$PREVIOUS_HEAD"
CURRENT_STASH_PATH="$ARTIFACT_STASH_PATH/$CURRENT_HEAD"
mkdir -p "$PREVIOUS_STASH_PATH"
# move current artifacts to an artifact stash directory
for path in $ARTIFACT_PATHS; do
    if [ -e "$path" ] ; then
        if [ -e "$CURRENT_STASH_PATH/$path" ] ; then
            echo "[artifact-cache] Stashing (mv) '$path' for $PREVIOUS_HEAD_SHORT..."
            mv "$path" "$PREVIOUS_STASH_PATH"
        else
            echo "[artifact-cache] Stashing (cp -a) '$path' for $PREVIOUS_HEAD_SHORT..."
            cp -a "$path" "$PREVIOUS_STASH_PATH"
        fi
    else
        echo "[artifact-cache] No '$path' found to stash for $PREVIOUS_HEAD_SHORT"
    fi
done
# restore an artifact stash directory if exists
if [ -d "$CURRENT_STASH_PATH" ]; then
    for path in $ARTIFACT_PATHS; do
        if [ -e "$CURRENT_STASH_PATH/$path" ] ; then
            echo "[artifact-cache] Restoring '$path' for $CURRENT_HEAD_SHORT..."
            mv "$CURRENT_STASH_PATH/$path" "$path"
        else
            echo "[artifact-cache] No '$path' found to restore for $CURRENT_HEAD_SHORT"
        fi
    done
    rm -rf "$CURRENT_STASH_PATH"
fi