post-commit

#!/bin/sh

# Copyright (c) 2016 by Thomas Weber
# Released under MIT License (see LICENSE file)

# We want to run LDoc to update the documentation, but we can't
# add files to a commit that's currently running. We use the method
# presented in the following link to check whether pre-commit ran
# and we need to update and add the documentation.
#   http://stackoverflow.com/questions/3284292#12802592
# If we don't add/delete the .commit "flag" file, then git reset
# would result in an infinitive loop if we abort the commit on
# ldoc errors


if [ -e ".commit" ]
then
  rm ".commit"
  # The current state of the documentation may contain changes that
  # were not committed yet. We don't want them to be in the current
  # commit.  Therefore we remove the documentation and re-generate
  # it from the state of the most recent commit.
  rm -rf doc
  # Because the working copy may contain stuff that is not yet part
  # of the last commit, we checkout the last commit and re-generate
  # the documentation from it.
  tmpCurrentCommitDir=$(mktemp -d)

  # We'll get an error "fatal: working tree [...] already exists" if we don't
  # unset GIT_WORK_TREE. See http://stackoverflow.com/questions/34224729
  unset GIT_WORK_TREE
  git clone . "$tmpCurrentCommitDir"

  # We run ldoc and check whether there is any output on stderr.
  # If so, there is something wrong and we abort the commit.
  errors=$(ldoc -iq "$tmpCurrentCommitDir" 2>&1 >/dev/null)
  if [ "$errors" ]
  then
    # The errors contain paths of the temporarily cloned repo. We remove that
    # temporary directory info to avoid confusion.
    errors=$(echo $errors | sed "s?${tmpCurrentCommitDir}/??g")
    echo $errors
    message="The commit with message\n\n"
    message="$message$(git log -1 --pretty=%B)"
    message="$message""\n\ncaused the following problem with LDoc:"
    message="$message\n\n$errors\n\n"
    message="$message""Revert commit?"
    if zenity --question --title="Commit problem" --text="$message"
    then
      git reset HEAD^
    else
      # Just pretend there were no errors
      errors=""
    fi
  fi

  if ! [ "$errors" ]
  then
    git add doc
    # --no-verify to bypass pre-commit and avoid looping
    git commit --amend -C HEAD --no-verify
  fi

  # Now we re-generate the documentation to represent the state of the
  # working copy and get rid of the temporary clone.
  #rm -rf "$tmpCurrentCommitDir"
  ldoc -iq .
fi