update_checkstyle_thresholds

#!/bin/bash
#
# This script updates the Checkstyle thresholds based on the most recent
# Checkstyle run (therefore, this script must be run after the Gradle "check"
# task has run).  If the thresholds have changed, the updated thresholds are
# pushed back to the remote repository.
#
# NOTE: There is no danger in INCREASING the thresholds because the build will
# have already failed at this point if the violation counts have increased.
#

readonly FALSE=1
readonly GRADLE_PROPERTIES=gradle.properties
readonly TRUE=0

main() {
  should_skip_build && exit 0

  local -r old_hash=$(get_gradle_properties_hash)
  update_local_thresholds
  has_local_thresholds_changed "$old_hash" && update_remote_thresholds "$old_hash"
}

should_skip_build() {
  echo "Checking if Checkstyle thresholds should be updated for this build..."
  local skip=$FALSE
  if [[ "$TRAVIS_PULL_REQUEST" != "false" ]]; then
    echo "  ...skipping because pull requests are not permitted."
    skip=$TRUE
  fi
  if [[ "$TRAVIS_BRANCH" != "master" ]]; then
    echo "  ...skipping because this branch is not permitted."
    skip=$TRUE
  fi
  if [[ "$TRAVIS_REPO_SLUG" != "triplea-game/triplea" ]]; then
    echo "  ...skipping because this repo is not permitted."
    skip=$TRUE
  fi
  return $skip
}

get_gradle_properties_hash() {
  git hash-object "$GRADLE_PROPERTIES"
}

update_local_thresholds() {
  echo "Updating Checkstyle thresholds..."
  update_threshold main.xml Main
  update_threshold test.xml Test
  update_threshold integTest.xml IntegTest
}

update_threshold() {
  local -r report_file=$1
  local -r violation_property_name=$2
  local -r checkstyle_warning_pattern='<error [^>]*severity="warning"'
  local -r checkstyle_reports_dir=build/reports/checkstyle
  local -r violation_count=$(grep -c "$checkstyle_warning_pattern" $checkstyle_reports_dir/$report_file)
  local -r violation_property="checkstyle${violation_property_name}MaxWarnings"
  sed -i -r "s/$violation_property=[[:digit:]]+/$violation_property=$violation_count/" $GRADLE_PROPERTIES
}

has_local_thresholds_changed() {
  echo "Checking for changes to '$GRADLE_PROPERTIES'..."
  local -r old_hash=$1
  local -r new_hash=$(get_gradle_properties_hash)
  if [[ "$old_hash" != "$new_hash" ]]; then
    echo "  ...changes detected."
    return $TRUE
  else
    echo "  ...no changes detected."
    return $FALSE
  fi
}

update_remote_thresholds() {
  echo "Pushing '$GRADLE_PROPERTIES' changes to '$TRAVIS_REPO_SLUG:$TRAVIS_BRANCH'..."
  local -r old_hash=$1
  local -r update_request="{ \
    \"message\": \"Bot: Update Checkstyle thresholds after build $TRAVIS_BUILD_NUMBER\", \
    \"committer\": { \
      \"name\": \"tripleabuilderbot\", \
      \"email\": \"tripleabuilderbot@gmail.com\" \
    }, \
    \"branch\": \"$TRAVIS_BRANCH\", \
    \"content\": \"$(base64 -w 0 $GRADLE_PROPERTIES)\", \
    \"sha\": \"$old_hash\" \
  }"
  curl \
      --silent \
      --show-error \
      -X PUT \
      --header "Accept: application/vnd.github.v3+json" \
      --data "$update_request" \
      --user ":$GITHUB_PERSONAL_ACCESS_TOKEN_FOR_TRAVIS" \
      "https://api.github.com/repos/$TRAVIS_REPO_SLUG/contents/$GRADLE_PROPERTIES"
}

main