#!/bin/sh
# Check the format of GNU Emacs change log entries.

# Copyright 2014 Free Software Foundation, Inc.

# This file is part of GNU Emacs.

# GNU Emacs is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# GNU Emacs is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.

# Written by Paul Eggert.

# Use a UTF-8 locale if available, so that the UTF-8 check works.
# Use U+00A2 CENT SIGN to test whether the locale works.
cent_sign_utf8_octal='\302\242'
at_sign=`
  printf "${cent_sign_utf8_octal}@" |
  awk '{print substr($0, 2)}' 2>/dev/null
`
if test "$at_sign" != @; then
  at_sign=`
    printf "${cent_sign_utf8_octal}@" |
    LC_ALL=en_US.utf8 awk '{print substr($0, 2)}' 2>/dev/null
  `
  if test "$at_sign" = @; then
    LC_ALL=en_US.utf8; export LC_ALL
  fi
fi

# Check the log entry.
exec awk '
  /^#/ { next }

  !/^.*$/ {
    print "Invalid character (not UTF-8)"
    status = 1
  }

  nlines == 0 && !/[^[:space:]]/ { next }

  { nlines++ }

  nlines == 1 && /^[[:space:]]/ {
    print "White space at start of first line"
    status = 1
  }

  nlines == 2 && /[^[:space:]]/ {
    print "Nonempty second line"
    status = 1
  }

  /[[:cntrl:]]/ {
    print "Text contains control character; please use spaces instead of tabs"
    status = 1
  }

  72 < length && /[[:space:]]/ {
    print "Line longer than 72 characters"
    status = 1
  }

  140 < length {
    print "Word longer than 140 characters"
    status = 1
  }

  /^Signed-off-by: / {
    print "'Signed-off-by:' present"
    status = 1
  }

  END {
    if (nlines == 0) {
      print "Empty change log entry"
      status = 1
    }
    exit status
  }
' <"$1"