Only run SwiftLint for chunks that differ from HEAD

swiftlint.sh

#!/bin/bash

# Parameters
source="$(pwd)/"                            # Track folder source where diffs are checked
project_root=${0%/*}                        # Track project root folder
swiftlint_path='swiftlint'                  # Track SwiftLint path

changed_files () {
  sort -u \
    <(git diff --name-only --diff-filter=d --cached) \
    <(git diff --name-only --diff-filter=d) \
    | egrep "${source#$(pwd)/}" \
    | egrep '.swift$'
}

diff_unified () {
  sort -u <(git diff --cached -U0 $1) <(git diff -U0 $1)
}

if [ ! "$(changed_files)" ]; then
  exit 0
fi

# Check if SwiftLint is installed
if [[ $(which swiftlint) == 'swiftlint not found' ]]; then
  echo "warning: SwiftLint not installed, download from https://github.com/realm/SwiftLint"
  exit 1
fi

cd $project_root
# Iterate through each modified file
while read file; do
  hunkCount=0                               # Track number of hunks
  hunkLines=()                              # Track each hunk range [start, end] = [hunkLines[i*2], hunkLines[i*2+1]]
  # Iterate through each git diff hunk
  while read hunk; do
    hunkCount=$((hunkCount+1))
    hunkLines+=(${hunk%%+*})                # Add hunk start line
    hunkLines+=($(echo $hunk | bc))         # Add hunk end line
  done< <(diff_unified $file | egrep '@@' | cut -d ' ' -f 3 | sed -e 's|+||' -e 's|,|+|')
  # Iterate through each violation from SwiftLint
  while read violation; do
    line=$(echo $violation | cut -d : -f 2) # Track violation line number
    # Iterate through each hunk range to see if violation applies
    for i in $(seq 0 $((hunkCount-1))); do
      # Check if violation is in range of hunk
      if [ "$line" -ge "${hunkLines[i*2]}" ] && [ "$line" -le "${hunkLines[i*2+1]}" ]; then
        # Violation output format is automatically recognized by Xcode
        echo $violation
        # Check if the violation contains an error, and exit immediately
        if [[ $violation == *" error: "* ]]; then exit 1; fi
        break
      fi
    done
  done< <($swiftlint_path lint --quiet --path $file)
done< <(changed_files)