scripts/release

#!/bin/bash
#
# Copyright 2017-present The Material Motion and Material Components for
# iOS Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# Abort if any command returns an error
set -e

parentcmd=$(basename "${BASH_SOURCE[1]}")
cmd=$(basename "${BASH_SOURCE[0]}")
dir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"

usage() {
  "$dir/readme_to_console" "$dir/README-release.md"
}

# HELPER METHODS

current_branch() {
  git rev-parse --abbrev-ref HEAD
}

enforce_clean_state() {
  if [[ $(git status --porcelain) ]]; then
    echo "${B}Your git repo is not in a clean state.${N}"
    echo "Please revert or commit all changes before cutting a release."
    git status
    exit 1
  fi
}

enforce_release_cut() {
  if [ ! $(git rev-parse --verify release-candidate 2> /dev/null) ]; then
    echo "No release in progress."
    exit 1
  fi
}

enforce_changelog_version() {
  changelog_version=$(awk '/# (.+)/ { print $2; exit}' "$rootdir/CHANGELOG.md")
  changelog_version=$(version_for_platform $changelog_version)
  if [ "$changelog_version" == "#develop#" ]; then
    echo "${B}You haven't updated CHANGELOG.md with the current version yet.${N}"
    echo "Please run '$parentcmd $cmd bump [version]' before running this command again."
    exit 1
  elif [ "$version" != "$changelog_version" ]; then
    echo "Mismatch in CHANGELOG.md's latest version."
    echo
    echo "    CHANGELOG.md latest version: $changelog_version"
    echo "                Desired version: $version"
    echo
    echo "Please edit CHANGELOG.md or change your version number."
    echo
    exit 1
  fi
}

get_latest_branch() {
  if [ ! $(git rev-parse --verify release-candidate 2> /dev/null) ]; then
    echo "HEAD"
  else
    echo "release-candidate"
  fi
}

version_for_platform() {
  user_version="$1"

  if [ -f "$rootdir/Podfile" ]; then
    echo "v${user_version#v}"
  elif [ -f "$rootdir/build.gradle" ]; then
    echo "${user_version#v}"
  else
    echo "v${user_version#v}"
  fi
}

# COMMAND METHODS

# Creates a release-candidate branch based off the latest origin/develop
cut_release() {
  isHotFix=false;

  while test $# -gt 0; do
    case "$1" in
      --hotfix)
        isHotFix=true;
        shift
        ;;
    esac
  done

  if [ $(git rev-parse --verify release-candidate 2> /dev/null) ]; then
    echo "${B}Release already cut.${N}"
    echo "Consider deleting your existing release-candidate branch."
    exit 1
  fi

  git fetch

  git show develop >> /dev/null 2>&1 || { git checkout -b develop origin/develop; }

  deviance=$(git log develop..origin/develop --oneline | wc -l)
  if [ $deviance -ne 0 ]; then
    echo
    echo "    Your local develop branch is behind origin/develop."
    echo "    Refusing to continue until you've rebased off of origin/develop."
    echo
    echo "    git checkout develop"
    echo "    git rebase origin/develop"
    echo
    exit 1
  fi

  deviance=$(git log origin/develop..develop --oneline | wc -l)
  if [ $deviance -ne "0" ]; then
    echo
    echo "    Your local develop branch is ahead of origin/develop."
    echo "    Refusing to continue until you've landed your local changes into origin/develop."
    echo
    exit 1 # TODO: Revert this line so we bail out.
  fi

  if $isHotFix; then
    branch=origin/stable
    branch_message="This is a hotfix... branching off $branch"
  else
    branch=origin/develop
    branch_message="This is a normal release... branching off $branch"
  fi
  echo $branch_message
  git checkout -b release-candidate $branch
  git checkout origin/stable -- .gitattributes

  touch "$rootdir/CHANGELOG.md"
  if ! grep "# #develop#" "$rootdir/CHANGELOG.md" >> /dev/null; then
    echo "Generating API diff..."
    CHANGELOG_TMP_PATH=$(mktemp -d)
    generate_release_apidiff | tee "$CHANGELOG_TMP_PATH/api_diff"

    CHANGELOG_PATH=$(cat "$CHANGELOG_TMP_PATH/api_diff" | grep "Changelog=" | cut -d'=' -f2)

    # Add the new changelog contents in reverse order:
    echo -e "\n---\n" | cat - "$rootdir/CHANGELOG.md" > /tmp/out && mv /tmp/out "$rootdir/CHANGELOG.md"
    generate_release_notes | cat - "$rootdir/CHANGELOG.md" > /tmp/out && mv /tmp/out "$rootdir/CHANGELOG.md"
    echo -e "\n## Component changes" | cat - "$rootdir/CHANGELOG.md" > /tmp/out && mv /tmp/out "$rootdir/CHANGELOG.md"
    cat "$CHANGELOG_PATH" | cat - "$rootdir/CHANGELOG.md" > /tmp/out && mv /tmp/out "$rootdir/CHANGELOG.md"
    echo -e "## API changes" | cat - "$rootdir/CHANGELOG.md" > /tmp/out && mv /tmp/out "$rootdir/CHANGELOG.md"
    echo -e "Replace this text with example code for each new feature." | cat - "$rootdir/CHANGELOG.md" > /tmp/out && mv /tmp/out "$rootdir/CHANGELOG.md"
    echo -e "## New features\n" | cat - "$rootdir/CHANGELOG.md" > /tmp/out && mv /tmp/out "$rootdir/CHANGELOG.md"
    echo -e "Replace this text with links to deprecation guides." | cat - "$rootdir/CHANGELOG.md" > /tmp/out && mv /tmp/out "$rootdir/CHANGELOG.md"
    echo -e "## New deprecations\n" | cat - "$rootdir/CHANGELOG.md" > /tmp/out && mv /tmp/out "$rootdir/CHANGELOG.md"
    echo -e "Replace this explanations for how to resolve the breaking changes." | cat - "$rootdir/CHANGELOG.md" > /tmp/out && mv /tmp/out "$rootdir/CHANGELOG.md"
    echo -e "## Breaking changes\n" | cat - "$rootdir/CHANGELOG.md" > /tmp/out && mv /tmp/out "$rootdir/CHANGELOG.md"
    echo -e "Replace this text with a summarized description of this release's contents." | cat - "$rootdir/CHANGELOG.md" > /tmp/out && mv /tmp/out "$rootdir/CHANGELOG.md"
    echo -e "# #develop#\n" | cat - "$rootdir/CHANGELOG.md" > /tmp/out && mv /tmp/out "$rootdir/CHANGELOG.md"
  fi
  git add "$rootdir/CHANGELOG.md"
  git commit -m "Automatic changelog preparation for release."
  git push origin release-candidate -u

  RELEASE_SHA=$(git merge-base --fork-point release-candidate $branch)
  PULL_REQUEST_URL="https://github.com/material-components/material-components-ios/compare/stable...release-candidate"
  echo "${B}You can now start the release-candidate pull request:${N}"
  echo
  echo "    $PULL_REQUEST_URL"
  echo
  echo "This will initiate public testing of the release candidate."
  echo
  echo "${B}You can now kick off internal testing.${N}"
}

abort_release() {
  enforce_release_cut

  echo "${B}About to abort the release candidate.${N}"
  echo "${B}${U}This action is not easily reversible.${N}"
  echo
  echo -n "Press enter to continue..."
  read

  git checkout origin/develop
  git branch -D release-candidate
  git push origin :release-candidate
}

test_release() {
  "$dir/prep_all"
  "$dir/build_all" --verbose
  "$dir/test_all"
  "$dir/build_codelabs"
}

bump_release() {
  if [ -z "$1" ]; then
    echo "Missing desired version."
    echo
    echo "Usage: $parentcmd $cmd bump <desired version> [<old version>]"
    echo
    exit 1
  fi

  enforce_release_cut

  new_version="$1"
  new_version=${new_version#v}

  if [ -z "$2" ]; then
    last_version=$(git describe --tags $(git rev-list --tags --max-count=1))
  else
    last_version="$2"
  fi
  last_version=${last_version#v}

  grep -FIlr "$last_version" . 2>/dev/null | grep -v -f "$dir/versionignore" | while read line; do
    sed -i.bak "s:$last_version:$new_version:g" "$line"
    rm "$line.bak"
  done

  grep -FIlr "#develop#" . 2>/dev/null | grep -v -f "$dir/versionignore" | while read line; do
    sed -i.bak "s:#develop#:$new_version:g" "$line"
    rm "$line.bak"
  done
}

merge_release() {
  enforce_release_cut

  version=$(version_for_platform $1)
  if [ -z "$version" ]; then
    echo "Must provide a ${U}version${N} argument."
    exit 1
  fi
  
  deviance=$(git log develop..origin/develop --oneline | wc -l)
  if [ $deviance -ne 0 ]; then
    echo
    echo "    Your local develop branch is behind origin/develop."
    echo "    Refusing to continue until you've rebased off of origin/develop."
    echo
    echo "    git checkout develop"
    echo "    git rebase origin/develop"
    echo
    exit 1
  fi
  
  deviance=$(git log origin/develop..develop --oneline | wc -l)
  if [ $deviance -ne "0" ]; then
    echo
    echo "    Your local develop branch is ahead of origin/develop."
    echo "    Refusing to continue until you've landed your local changes into origin/develop."
    echo
    exit 1 # TODO: Revert this line so we bail out.
  fi

  current_branch=$(current_branch)
  if [ "$current_branch" != "release-candidate" ]; then
    echo "Checking out the release-candidate branch..."
    git checkout release-candidate
  fi

  enforce_changelog_version

  if [ $(git rev-list --tags --max-count=1 2> /dev/null) ]; then
    last_version=$(git describe --tags $(git rev-list --tags --max-count=1))
    last_version=${last_version#v}
    last_version=$(echo "$last_version" | sed "s:\.:\\\\.:g")
    if grep -Ilr "$last_version" . | grep -v -f "$dir/versionignore"; then
      echo "Old version $last_version found in the files above."
      read -r -p "Continue? [y/N] " response
      case $response in
        [yY][eE][sS]|[yY]) ;;
        *)
          echo "Aborting release merge. Please run $parentcmd $cmd bump"
          exit 1
          ;;
      esac
    fi
  fi

  echo "Merging release-candidate into stable and develop..."
  
  # Legend of commits.
  # Each numbered commit corresponds to a set of commands below, with all `o` symbols having been
  # committed by earlier steps in the release process.
  #
  #           develop o-o----------3
  #                      \        /
  # release-candidate     o--o---2
  #                           \ /
  #            stable o--------1

  # Commit #1: Create the releasable merge commit in stable.
  git fetch
  if [ ! $(git rev-parse --verify stable 2> /dev/null) ]; then
    git checkout -b stable origin/stable
  else
    git checkout stable
  fi
  git rebase origin/stable
  git merge --no-ff release-candidate --no-edit

  # Commit #2: Connect stable to develop's ancestry by merging stable back into the
  # release-candidate.
  git checkout release-candidate
  git merge --no-ff stable --no-edit

  # Commit #3: Merge the release-candidate into develop.
  if [ ! $(git rev-parse --verify develop 2> /dev/null) ]; then
    git checkout -b develop origin/develop
  else
    git checkout develop
  fi
  git rebase origin/develop
  # The following lines will only create one commit thanks to the --no-commit argument here.
  git merge --no-ff --no-commit release-candidate --no-edit
  git reset HEAD .gitattributes
  git checkout -- .gitattributes
  git commit -m "merged release-candidate"
  git branch -D release-candidate

  git checkout stable
}

publish_release() {
  version=$(version_for_platform $1)
  if [ -z "$version" ]; then
    echo "Must provide a ${U}version${N} argument."
    exit 1
  fi

  current_branch=$(current_branch)
  if [ "$current_branch" != "stable" ]; then
    echo "This command must be run from the ${B}stable${N} branch."
    echo
    echo "Your current branch: $current_branch"
    exit 1
  fi

  enforce_changelog_version

  ghtoken="$(cut -d " " -f 2 <<< $(cat ~/.config/gh/hosts.yml | grep "oauth_token: "))"
  if [ -z "$ghtoken" ]; then
    echo "Error: Unable to find a token in ~/.config/gh/hosts.yml."
    echo
    echo "You must authenticate with the official GitHub command line interface tool:"
    echo "https://github.com/cli/cli"
    echo
    echo "Not to be confused with the following unofficial (and no longer maintained) GitHub command line tool that this script used to use:"
    echo "https://github.com/node-gh/gh"
    echo
    echo "To proceed, do the following:"
    echo "1. Install the official command line tool"
    echo "2. Authenticate using 'gh auth login'"
    echo "    a. When it asks 'What account do you want to log into?', choose 'GitHub.com'"
    echo "    b. When it asks 'How would you like to authenticate?', choose 'Login with a web browser'"
    echo "3. Re-run the scripts/release command"
    echo
    echo "You will probably have to delete or move the old gh to make way for the new (official) one."
    exit 1
  fi

  curl -sH "Authorization: token $ghtoken" \
    "https://api.github.com/repos/material-components/material-components-ios/releases/tags/$version" \
    | grep -q 'message": "Not Found'

  if [ $? -ne 0 ]; then # Found the release
    echo "Release already cut."
    echo
    echo "    Release URL: https://github.com/material-components/material-components-ios/releases/tag/$version"
    open "https://github.com/material-components/material-components-ios/releases/tag/$version"
    exit 0
  fi

  git push origin stable develop

  tmp_path=$(mktemp -d)

  curl -s \
    -H "Authorization: token $ghtoken" \
    -H "Content-Type: application/json" \
    -X POST \
    -d '{"tag_name":"'$version'","target_commitish":"stable","name":"'$version'","draft":true}' \
    "https://api.github.com/repos/material-components/material-components-ios/releases" > "$tmp_path/release"

  if [ $? -ne 0 ]; then # Found the release
    echo "Failed to draft the release. Check that it doesn't already exist before continuing."
    echo "https://api.github.com/repos/material-components/material-components-ios/releases"
    exit 1
  fi

  htmlurl=$(cat "$tmp_path/release" | grep '^  "html_url' | cut -d'"' -f4)
  htmlurl=$(echo $htmlurl | sed "s:/tag/:/edit/:")

  echo "A draft release has been made."
  echo
  echo "    Edit the draft: $htmlurl"
  echo
  echo "Update the release's description with the following:${B}"
  awk '/# / { print $0; while(getline > 0) {if (/^# /) exit; print $0 }}' "$rootdir/CHANGELOG.md" | tail -n +2
  echo ${N}

  echo "Deleting remote release-candidate..."
  git push origin :release-candidate

  git checkout develop

  echo "Press enter to open the release draft url in your browser:"
  read

  if [ "$(uname)" == "Darwin" ]; then
    open $htmlurl
  elif [ "$(expr substr $(uname -s) 1 5)" == "Linux" ]; then
    xdg-open $htmlurl
  fi
}

publish_podspec() {
  cat <<EOL
          |\\___/|
         (,\\  /,)\\
         /     /  \\       DRAGON SAYS HALT:
        (@_^_@)/   \\      HAS THE INTERNAL CL LANDED?
         W//W_/     \\     DO NOT PUBLISH THIS RELEASE UNTIL
       (//) |        \\    IT HAS LANDED.
     (/ /) _|_ /   )  \\
   (// /) '/,_ _ _/  (~^-.
 (( // )) ,-{        _    \`.
(( /// ))  '/\\      /       \\
(( ///))     \`.   {       }  \\
 ((/ ))    .----~-.\\   \\-'    ~-__
          ///.----..>   \\ \\_      ~--____
           ///-._ _  _ _}    ~--------------
EOL
  echo "Press enter to confirm that the internal CL has landed."
  read

  cd "$rootdir"
  echo "Verifying Cocoapod trunk permissions"
  pod trunk me > cocoapods_permissions.log
  if grep -Fq "MaterialComponents" cocoapods_permissions.log; then
    echo "Running a pod trunk push from stable..."
    git checkout stable
    pod trunk push MaterialComponents.podspec
    rm cocoapods_permissions.log
  else
    echo "You do not have the right permissions to push the pod via the CocoaPods API. See cocoapods_permissions.log for more info."
  fi
}

# Generators

generate_release_apidiff() {
  CHANGELOG_TMP_PATH=$(mktemp -d)

  validate_commit() {
    git cat-file -t $1 >> /dev/null 2> /dev/null || { echo "$1 is not a valid commit."; exit 1; }
  }

  # Verify commits
  if [ -n "$1" ]; then
    old_commit=$(git rev-list -n 1 $1)
  else
    old_commit=$(git rev-list -n 1 origin/stable)
  fi
  new_commit=$(git rev-list -n 1 $(get_latest_branch))

  if [[ -z "$old_commit" || -z "$new_commit" ]]; then
    echo "Unable to get commit shas."
    exit 1
  fi

  validate_commit $old_commit
  validate_commit $new_commit

  TMP_PATH=$(mktemp -d)
  OLD_ROOT_PATH="$TMP_PATH/old"
  NEW_ROOT_PATH="$TMP_PATH/new"
  clean_clones() {
    if [ ! -z "$OLD_ROOT_PATH" ]; then
      rm -rf "$OLD_ROOT_PATH"
    fi
    if [ ! -z "$NEW_ROOT_PATH" ]; then
      rm -rf "$NEW_ROOT_PATH"
    fi
  }
  trap clean_clones EXIT

  # We do not need LFS for the temporary clones; they are used solely to do API diffs.
  # See https://github.com/git-lfs/git-lfs/issues/2406 for where this flag came from.
  export GIT_LFS_SKIP_SMUDGE=1

  "$dir/temporary_clone_at_ref" "$OLD_ROOT_PATH" $old_commit
  "$dir/temporary_clone_at_ref" "$NEW_ROOT_PATH" $new_commit
  
  unset GIT_LFS_SKIP_SMUDGE

  # Find command in all component src directories and grab search path for "Material$component.h"
  old_header_search_paths=""
  new_header_search_paths=""
  for d in $NEW_ROOT_PATH/components/*/src; do
    folder=$(dirname $d)
    component=$(basename $folder)
    old_header_search_paths="$old_header_search_paths --oldargs -I$OLD_ROOT_PATH/components/$component/src/ "
    new_header_search_paths="$new_header_search_paths --newargs -I$NEW_ROOT_PATH/components/$component/src/ "
  done

  if [ ! -f "$dir/external/material-motion-apidiff/src/pathapidiff" ]; then
    git submodule update --init --recursive
  fi

  ALL_CHANGELOG_PATH="$TMP_PATH/changelog"
  ALL_ERROR_LOG_PATH="$TMP_PATH/errlog"

  echo "Changelog=$ALL_CHANGELOG_PATH"
  echo "Errors=$ALL_ERROR_LOG_PATH"

  # Run new pathdiff script on each umbrella header in array
  for umbrella_header_path in $(generate_release_umbrella_headers "$old_commit" | grep -v "private"); do
    umbrella_header=$(basename "$umbrella_header_path")
    component=$(echo "$umbrella_header" | cut -d'.' -f1 | sed 's:^Material::')
    component_path=$(dirname "$umbrella_header_path")

    echo -n "Diffing $component ($component_path)..."

    if [ ! -f "$OLD_ROOT_PATH/$umbrella_header_path" ]; then
      echo >> $ALL_CHANGELOG_PATH
      echo "### $component" >> $ALL_CHANGELOG_PATH
      echo >> $ALL_CHANGELOG_PATH
      if [[ "$component" = *"+"* ]]; then
        echo "**New extension.**" >> $ALL_CHANGELOG_PATH
      else
        echo "**New component.**" >> $ALL_CHANGELOG_PATH
      fi

      echo "New!"
      continue
    fi

    CHANGES_PATH="$TMP_PATH/${component}changes"
    ERROR_PATH="$TMP_PATH/${component}errlog"

    "$dir/external/material-motion-apidiff/src/pathapidiff" \
       "$OLD_ROOT_PATH" "$NEW_ROOT_PATH" objc "/$umbrella_header_path" \
       >> "$CHANGES_PATH" \
       2>> "$ERROR_PATH"

    if [ -s "$CHANGES_PATH" ]; then
      echo >> $ALL_CHANGELOG_PATH
      echo "### $component" >> $ALL_CHANGELOG_PATH
      cat "$CHANGES_PATH" >> $ALL_CHANGELOG_PATH

      echo -n " Changes detected."
    fi

    if [ -s "$ERROR_PATH" ]; then
      echo "### $component" >> "$ALL_ERROR_LOG_PATH"
      cat "$ERROR_PATH" >> "$ALL_ERROR_LOG_PATH"
    fi

    echo
  done
}

generate_release_authors() {
  git log origin/stable...$(get_latest_branch) --format="%ae" | sort | uniq
}

generate_release_components() {
  if [ -n "$1" ]; then
    old_commit="$1"
  else
    old_commit=origin/stable
  fi
  git diff --name-only "$old_commit"..$(get_latest_branch) components/ \
    | grep "src/" | cut -d'/' -f2- | rev | cut -d'/' -f3- | rev | sed 's|/src||' | sort | uniq
}

generate_release_files() {
  if [ -n "$1" ]; then
    old_commit="$1"
  else
    old_commit=origin/stable
  fi
  git diff --name-only "$old_commit"..$(get_latest_branch) components/
}

generate_release_umbrella_headers() {
  for file in $(generate_release_files "$@"); do
    file_dir=$(dirname $file)
    if ls "$file_dir"/Material*.h 1> /dev/null 2>&1; then
      ls "$file_dir"/Material*.h | grep -v "_table"
    fi
  done | sort | uniq
}

generate_release_headers() {
  git diff --name-only origin/stable..$(get_latest_branch) components/ \
    | grep -i -e "components\/.*\/src\/.*\.h" \
    | grep -v -i -e "\/private\/"
}

generate_release_log() {
  git --no-pager log  origin/stable..$(get_latest_branch) "$@"
}

generate_release_diff() {
  git_diff=diff
  if [ "$1" == "--use_diff_tool" ]; then
    git_diff=difftool
    shift 1
  fi

  git $git_diff origin/stable..$(get_latest_branch) "$@"
}

generate_release_notes() {
  # Echoes the SHA's title as a CHANGELOG.md entry.
  sha_to_changelog_entry() {
    sha="$1"
    git log \
      -1 \
      --pretty="* [%s](https://github.com/material-components/material-components-ios/commit/%H) (%an)" \
      --no-merges \
      "$sha"
  }
  # Returns a non-zero value if the given SHA affects any paths other than the given path.
  # Ignores modifications to MaterialComponents.podspec.
  does_commit_affect_other_paths() {
    sha="$1"
    path="$2"
    git diff-tree --no-commit-id --name-only -r "$sha" \
      | grep -v "$path" \
      | grep -v "MaterialComponents.podspec" \
      | grep -v "MaterialComponentsBeta.podspec" \
      | grep -v "catalog/Podfile" \
      | grep -v "snapshot_test_goldens"
  }
  # Echoes a list of changelog entries that affect a given path and only that path.
  changes_for_path() {
    path="${1:-components/}"
    git log \
        --pretty="%H" \
        --no-merges \
        origin/stable..$(get_latest_branch) "$path" | while read sha; do
      if [[ ! $(does_commit_affect_other_paths "$sha" "$path") ]]; then
        sha_to_changelog_entry "$sha"
      fi
    done
  }
  # Echoes a list of changes that affect the given path AND other paths.
  changes_for_multiple_paths() {
    path="${1:-components/}"
    git log \
        --pretty="%H" \
        --no-merges \
        origin/stable..$(get_latest_branch) "$path" | while read sha; do
      if [[ $(does_commit_affect_other_paths "$sha" "$path") ]]; then
        sha_to_changelog_entry "$sha"
      fi
    done
  }
  # Echoes a list of breaking changelog entries for a given path.
  filter_breaking_changes() {
    cat - | grep "\[.*\]\!" | perl -pe "s|\* \[\[.+?\]!|* [**Breaking**:|" | sort
  }
  # Echoes a list of non-breaking changelog entries for a given path.
  filter_non_breaking_changes() {
    cat - | grep -v "\[.*\]\!" | perl -pe "s|\* \[\[.+?\] |* [|" | sort
  }

  has_breaking_changes=false
  has_non_breaking_changes=false

  # Output breaking changes that affect specific components.

  find components -type d -name 'src' | sort | while read path; do
    folder=$(dirname $path)

    if [[ $(changes_for_path "$folder" | filter_breaking_changes) ]]; then
      component=$(echo $folder | cut -d'/' -f2-)

      if [ "$has_breaking_changes" = false ]; then
        has_breaking_changes=true
        echo
        echo "## Breaking changes"
      fi
      echo
      echo "### $component"
      echo

      changes_for_path "$folder" | filter_breaking_changes
    fi
  done

  # Output breaking changes that affect multiple components.

  all_breaking_changes_for_multiple_paths() {
    find components -type d -name 'src' | while read path; do
      folder=$(dirname $path)
      changes_for_multiple_paths "$folder" | filter_breaking_changes
    done | sort | uniq
  }
  if [[ $(all_breaking_changes_for_multiple_paths) ]]; then
    has_breaking_changes=true
    echo
    echo "## Multi-component breaking changes"
    echo
    all_breaking_changes_for_multiple_paths
  fi

  # Output changes that affect specific components.

  find components -type d -name 'src' | sort | while read path; do
    folder=$(dirname $path)

    if [[ $(changes_for_path "$folder" | filter_non_breaking_changes) ]]; then
      component=$(echo $folder | cut -d'/' -f2-)

      echo
      echo "### $component"
      echo

      changes_for_path "$folder" | filter_non_breaking_changes
    fi
  done

  # Output changes that affect multiple components.

  all_non_breaking_changes_for_multiple_paths() {
    find components -type d -name 'src' | while read path; do
      folder=$(dirname $path)
      changes_for_multiple_paths "$folder" | filter_non_breaking_changes
    done | sort | uniq
  }
  if [[ $(all_non_breaking_changes_for_multiple_paths) ]]; then
    has_non_breaking_changes=true
    echo
    echo "## Multi-component changes"
    echo
    all_non_breaking_changes_for_multiple_paths
  fi
}

other_thing() {
  find components -type d -name 'src' | sort | while read path; do
    folder=$(dirname $path)
    component=$(echo $folder | cut -d'/' -f2-)

    if [[ $component == private* ]]; then
      continue;
    fi

    if [ $(git log --pretty=oneline --no-merges origin/stable..$(get_latest_branch) $folder \
           | wc -l) == "0" ]; then
      continue
    fi

    componentdiff() {
      git log \
        --pretty="* [%s](https://github.com/material-components/material-components-ios/commit/%H) (%an)" \
        --no-merges \
        origin/stable..$(get_latest_branch) \
        $folder | grep -v "\[automated\]"
    }

    if [[ $(componentdiff) ]]; then
      echo
      echo "### $component"

      if [[ $(componentdiff | grep "\[$component\]\!") ]]; then
        echo
        echo "#### Breaking changes"
        echo

        componentdiff \
          | grep "\[$component\]\!" \
          | sed "s|\[$component\]!|**Breaking**: |" \
          | sort
      fi

      if [[ $(componentdiff | grep -v "\[$component\]\!") ]]; then
        echo

        componentdiff \
          | grep -v "\[$component\]!" \
          | sed "s|\[$component\] ||" \
          | sort
      fi
    fi

  done
}

generate_release_source() {
  git diff --name-only origin/stable..$(get_latest_branch) components/ \
    | grep "src/"
}

generate_release_stories() {
  generate_release_log | grep -i pivotal
}

if [ $# -eq 0 ]; then
  usage
  exit 1
fi

if [ ! $(git rev-parse --is-inside-work-tree -q 2> /dev/null) ]; then
  echo "Must be run from a git directory."
  exit 1
fi

if [ -t 1 ] ; then # We're writing directly to terminal
  readonly B=$(tput bold)
  readonly U=$(tput smul)
  readonly N=$(tput sgr0)
else # We're in a pipe
  readonly B=""
  readonly U=""
  readonly N=""
fi

rootdir=$( cd "$(dirname $(git rev-parse --git-dir))" && pwd )

#enforce_clean_state

case "$1" in
  cut)        cut_release ${@:2} ;;
  test)       test_release ${@:2} ;;
  bump)       bump_release ${@:2} ;;
  merge)      merge_release ${@:2} ;;
  publish)    publish_release ${@:2} ;;
  podspec)    publish_podspec ${@:2} ;;

  apidiff)    generate_release_apidiff ${@:2} ;; # args: [base sha]
  authors)    generate_release_authors ${@:2} ;;
  components) generate_release_components ${@:2} ;; # args: [base sha]
  diff)       generate_release_diff ${@:2} ;;
  files)      generate_release_files ${@:2} ;; # args: [base sha]
  headers)    generate_release_headers ${@:2} ;;
  log)        generate_release_log ${@:2} ;;
  notes)      generate_release_notes ${@:2} ;;
  source)     generate_release_source ${@:2} ;;
  stories)    generate_release_stories ${@:2} ;;
  umbrellas)  generate_release_umbrella_headers ${@:2} ;; # args: [base sha]

  abort)      abort_release ${@:2} ;;

  *)          usage ;;
esac