bug#39944: 27.0.90; JIT Stealth timer errors

[Eli Zaretskii]

I see these errors in the 27.0.90 pretest from time to time:

  Error running timer ‘jit-lock-stealth-fontify’: (error "Invalid time format")

This didn't happen in previous versions of Emacs, so I think this is
some regression, most probably due to changes in timer.el or related
time functions.

Does anyone else see this?  (You have to enable jit-lock-stealth to
see this.)


In GNU Emacs 27.0.90 (build 1, i686-pc-mingw32)
 of 2020-03-01 built on HOME-C4E4A596F7
Windowing system distributor 'Microsoft Corp.', version 5.1.2600
System Description: Microsoft Windows XP Service Pack 3 (v5.1.0.2600)

Recent messages:
Getting mail from d:/usr/eli/data/mail.new...
Counting new messages...done (1)
Saving file d:/usr/eli/rmail/INBOX...
Wrote d:/usr/eli/rmail/INBOX
Computing summary lines...done
1 new message read
No following nondeleted message
Saving file d:/usr/eli/rmail/INBOX...
Wrote d:/usr/eli/rmail/INBOX
Error running timer ‘jit-lock-stealth-fontify’: (error "Invalid time format") 
[2 times]

Configured using:
 'configure -C --prefix=/d/usr --with-wide-int --with-modules
 'CFLAGS=-Og -gdwarf-4 -g3''

Configured features:
XPM JPEG TIFF GIF PNG RSVG SOUND NOTIFY W32NOTIFY ACL GNUTLS LIBXML2
HARFBUZZ ZLIB TOOLKIT_SCROLL_BARS MODULES THREADS JSON PDUMPER LCMS2
GMP

Important settings:
  value of $LANG: ENU
  locale-coding-system: cp1255

Major mode: RMAIL

Minor modes in effect:
  shell-dirtrack-mode: t
  desktop-save-mode: t
  save-place-mode: t
  show-paren-mode: t
  display-battery-mode: t
  display-time-mode: t
  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
  temp-buffer-resize-mode: t
  buffer-read-only: t
  line-number-mode: t

Load-path shadows:
d:/usr/share/emacs/site-lisp/soap-inspect hides 
d:/usr/share/emacs/27.0.90/lisp/net/soap-inspect
d:/usr/share/emacs/site-lisp/soap-client hides 
d:/usr/share/emacs/27.0.90/lisp/net/soap-client

Features:
(shadow emacsbug pcase shell pcomplete comint ansi-color rfc2104
gnutls network-stream nsm mail-extr smtpmail mailalias sendmail
eieio-opt speedbar sb-image ezimage dframe find-func mule-diag
help-fns radix-tree misearch multi-isearch time-stamp shr-color color
shr url-cookie url-domsuf url-util url-parse auth-source json map
url-vars svg xml dom browse-url cl-extra help-mode make-mode conf-mode
bat-mode noutline outline cc-awk jka-compr vc-cvs vc-dispatcher vc-bzr
texinfo mule-util info view enriched flyspell add-log vc-git diff-mode
easy-mmode bug-reference rmailsum qp rmailmm message rmc puny
format-spec rfc822 mml mml-sec password-cache epa epg epg-config
gnus-util text-property-search time-date subr-x seq mm-decode
mm-bodies mm-encode mailabbrev gmm-utils mailheader mail-parse rfc2231
rmail rmail-loaddefs rfc2047 rfc2045 ietf-drums mm-util mail-prsvr
mail-utils desktop frameset server find-lisp dired dired-loaddefs
filecache mairix cus-edit cus-start cus-load wid-edit saveplace
midnight ispell derived generic-x cc-mode cc-fonts easymenu cc-guess
cc-menus cc-cmds cc-styles cc-align cc-engine cc-vars cc-defs paren
xref cl-seq project ring eieio byte-opt bytecomp byte-compile cconv
eieio-core cl-macs gv eieio-loaddefs cl-loaddefs cl-lib battery time
tooltip eldoc electric uniquify ediff-hook vc-hooks lisp-float-type
mwheel dos-w32 ls-lisp disp-table term/w32-win w32-win w32-vars
term/common-win tool-bar dnd fontset image regexp-opt fringe
tabulated-list replace newcomment text-mode elisp-mode lisp-mode
prog-mode register page tab-bar menu-bar rfn-eshadow isearch timer
select scroll-bar mouse jit-lock font-lock syntax facemenu font-core
term/tty-colors frame minibuffer 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 composite charscript charprop case-table
epa-hook jka-cmpr-hook help simple abbrev obarray 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 threads w32notify w32 lcms2
multi-tty make-network-process emacs)

Memory information:
((conses 16 526189 45228)
 (symbols 48 20376 1)
 (strings 16 118191 2769)
 (string-bytes 1 3365518)
 (vectors 16 32257)
 (vector-slots 8 464721 70974)
 (floats 8 282 384)
 (intervals 40 56525 1222)
 (buffers 888 238))