bug#24359: 25.1; batch-byte-compile exits with code 0 even if errors occurred

[Philipp <p.stephani2@gmail.com>]

Create a file /tmp/a.el with the following content:

;;; -*- lexical-binding: t; -*-
(let (a)
  (add-to-list 'a t))

Then run:

$ emacs -batch -Q -f batch-byte-compile /tmp/a.el ; echo $?

In toplevel form:
/tmp/a.el:2:1:Error: ‘add-to-list’ can’t use lexical var ‘a’; use ‘push’ or
    ‘cl-pushnew’
0

Expected behavior: The status code is nonzero because an error occurred.

Actual behavior: The status code is zero.

This is because this class of error (and others) use
byte-compile-log-warning, which doesn't properly set the error flag.



In GNU Emacs 25.1.3 (x86_64-unknown-linux-gnu, GTK+ Version 3.10.8)
 of 2016-09-03 built on unknown
Repository revision: 803ad6f7e7a9c6bcf8a6cbf8eaad17501b114a33
Windowing system distributor 'The X.Org Foundation', version 11.0.11702000
System Description:	Ubuntu 14.04 LTS

Configured features:
XPM JPEG TIFF GIF PNG SOUND GSETTINGS NOTIFY GNUTLS FREETYPE XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11

Important settings:
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message dired format-spec rfc822 mml
mml-sec password-cache epg epg-config gnus-util mm-decode mm-bodies
mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail
rfc2047 rfc2045 ietf-drums mm-util help-fns help-mode easymenu
cl-loaddefs pcase cl-lib mail-prsvr mail-utils time-date mule-util
tooltip eldoc electric uniquify ediff-hook vc-hooks lisp-float-type
mwheel x-win term/common-win x-dnd tool-bar dnd fontset image regexp-opt
fringe tabulated-list newcomment elisp-mode lisp-mode prog-mode register
page menu-bar rfn-eshadow timer select scroll-bar mouse jit-lock
font-lock syntax facemenu font-core frame cl-generic cham georgian
utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean
japanese eucjp-ms cp51932 hebrew greek romanian slovak czech european
ethiopic indian cyrillic chinese charscript case-table epa-hook
jka-cmpr-hook help simple abbrev minibuffer cl-preloaded nadvice
loaddefs button faces cus-face macroexp files text-properties overlay
sha1 md5 base64 format env code-pages mule custom widget
hashtable-print-readable backquote inotify dynamic-setting
system-font-setting font-render-setting move-toolbar gtk x-toolkit x
multi-tty make-network-process emacs)

Memory information:
((conses 16 87400 6705)
 (symbols 48 19696 0)
 (miscs 40 300 146)
 (strings 32 14554 3984)
 (string-bytes 1 425298)
 (vectors 16 11995)
 (vector-slots 8 435911 5924)
 (floats 8 162 31)
 (intervals 56 184 0)
 (buffers 976 22)
 (heap 1024 35418 1075))