PreCommitHook for SwiftLint

PreCommitHook.sh

#!/bin/bash

# COLOR codes to use in logs
RED='\033[0;31m'
YELLOW='\033[1;33m'
GREEN='\033[0;32m'
BOLD='\033[1m'
NC='\033[0m' # No Color

# LOG tag of file
LOG_TAG="PRE_COMMIT_HOOK_LOG :: "
# swiftlint.yml path.
LINT_CONFIG_FILE=".swiftlint.yml"

set -e

# check if lint exists.
if ! command -v swiftlint &> /dev/null
then
    echo -e "${LOG_TAG}${RED}SwiftLint could not be found. Please install it in your computer.${NC}"
    exit 1
fi

echo -e "${LOG_TAG}Linting..."

#Always lint one file to prevent "No lintable files found at paths: ''"
export SCRIPT_INPUT_FILE_0="##Put one of your files with its path that will always be in your project. (For Ex: AppDelegate)"
# This variable will store the files that needs to be re-added after auto fix. 
FILES_TO_ADD=""
swiftFileCount=1

# We will count the changed files and apply lint only for them.
while IFS= read -r file_path; do
    export SCRIPT_INPUT_FILE_$swiftFileCount="$file_path"
    swiftFileCount=$((swiftFileCount + 1))
    # We should escape from whitespace paths.
    escaped_path="${file_path// /\\ }"
    FILES_TO_ADD+="'$escaped_path' " 
done < <(git diff --diff-filter=d --name-only --cached | grep ".swift$")

echo -e "${LOG_TAG}The count of Swift files you changed and add to git is '${BOLD}$swiftFileCount${NC}'"

# In case there is no change besides the default 'Classes/Constants.swift' don't run the lint
if [ "$swiftFileCount" -ne 1 ]; then
    export SCRIPT_INPUT_FILE_COUNT=$swiftFileCount

    if swiftlint --fix --strict --use-script-input-files --config $LINT_CONFIG_FILE && swiftlint --use-script-input-files --config $LINT_CONFIG_FILE --force-exclude --strict; then
        # Re-add files after lint fix. Otherwise we can't send the auto fixed codes to the remote.
        # adding with echo prevents incorrect file addings.
        echo "git add ${FILES_TO_ADD}"
        echo -e "${GREEN}${LOG_TAG}No Swift Lint violations found. Your commit is good to go.${NC}"
        exit 0
    else
        echo -e "${RED}${LOG_TAG}'${BOLD}swiftlint fix${NC}' ${RED}could not fix the problem. Please check the link failures in your code!!!${NC}"
        exit 1
    fi
else
    echo -e "${LOG_TAG}${YELLOW}No files to lint!${NC}"
    exit 0
fi

# Unset the environment variables
unset "SCRIPT_INPUT_FILE_COUNT"
for ((i=0; i<swiftFileCount; i++)); do
    unset "SCRIPT_INPUT_FILE_$i"
done