When on-disk file has changed, I use the following function to re-read
buffer:

(defun refresh-file ()
  (interactive)
  (revert-buffer t (not (buffer-modified-p)) t)
  )

(global-set-key [f5] 'refresh-file)

I have seen (again this morning) I wind up with a corrupted buffer.  It
appears a segment of the data is correct, but data has been reordered.
I'm looking at a python source file.  For example, in the middle of the
buffer, it
looks like the beginning of the file is inserted (sorry I no longer have
this buffer and can't be precise).

Kill buffer, and reload file, and it's fixed.




In GNU Emacs 24.4.1 (x86_64-redhat-linux-gnu, GTK+ Version 3.14.11)
 of 2015-04-07 on buildvm-06.phx2.fedoraproject.org
Windowing system distributor `Fedora Project', version 11.0.11603000
System Description: Fedora release 21 (Twenty One)

Configured using:
 `configure --build=x86_64-redhat-linux-gnu
 --host=x86_64-redhat-linux-gnu --program-prefix=
 --disable-dependency-tracking --prefix=/usr --exec-prefix=/usr
 --bindir=/usr/bin --sbindir=/usr/sbin --sysconfdir=/etc
 --datadir=/usr/share --includedir=/usr/include --libdir=/usr/lib64
 --libexecdir=/usr/libexec --localstatedir=/var
 --sharedstatedir=/var/lib --mandir=/usr/share/man
 --infodir=/usr/share/info --with-dbus --with-gif --with-jpeg --with-png
 --with-rsvg --with-tiff --with-xft --with-xpm --with-x-toolkit=gtk3
 --with-gpm=no build_alias=x86_64-redhat-linux-gnu
 host_alias=x86_64-redhat-linux-gnu 'CFLAGS=-DMAIL_USE_LOCKF -O2 -g
 -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2
 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4
 -grecord-gcc-switches -m64 -mtune=generic' 'LDFLAGS=-Wl,-z,relro ''

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

Major mode: Python

Minor modes in effect:
  diff-auto-refine-mode: t
  jedi-mode: t
  global-auto-complete-mode: t
  auto-complete-mode: t
  display-time-mode: t
  override-global-mode: t
  shell-dirtrack-mode: t
  delete-selection-mode: t
  tooltip-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 input:
<prior> <up> <up> <up> <up> <up> <up> <up> <up> <up>
<up> C-SPC <down> <down> <down> C-c # C-x C-s C-x v
v C-x v = C-x o r e m o v e <backspace> <backspace>
<backspace> <backspace> <backspace> <backspace> c l
e a n u p C-c C-c M-x s h e l l <return> M-p <return>
C-x C-f t e s T _ u <tab> <backspace> <backspace> <backspace>
t _ u <tab> <return> y e s <return> <C-home> C-s c
o n s i d e r e d C-s C-s C-s C-s C-a C-s c o n s i
d C-s C-a <next> <next> <next> <prior> C-x k <return>
C-x C-f t e s t _ u <tab> <return> C-s c o n s i d
e r e d C-s C-s C-s C-s C-s C-r C-r C-a C-s C-s C-s
C-a C-h c <f5> C-h f r e f r e s h - f i l e <return>
C-x C-f C-g C-x o C-e <left> <left> <left> <return>
<help-echo> <help-echo> <help-echo> C-h v e m a c s
- v e r <tab> <return> <help-echo> <help-echo> <help-echo>
C-SPC <down> <down> <down> <down> <down> <down> M-w
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
C-x C-f <return> C-x 1 g <down> f C-x C-f t e s C-g
C-x b t e s t _ u <tab> <return> C-s - - l i m i t
- C-r C-r C-a C-r l i m i t _ n e w <help-echo> <help-echo>
<help-echo> C-a C-s p a r t i a l C-a <help-echo> C-x
C-f <return> g <down> <down> <down> <down> <down> <down>
<down> <down> <down> <down> <down> <down> <down> <down>
<down> <down> <down> <down> <down> <down> f <help-echo>
<help-echo> M-x r e p o r t <tab> <return>

Recent messages:
Type C-x 1 to delete the help window.
Quit

Mark set
Directory has changed on disk; type g to update Dired
Quit
Mark saved where search started [3 times]
Directory has changed on disk; type g to update Dired
Local value of py-indent-offset set to 4
Using the CPython shell

Load-path shadows:
/home/nbecker/.emacs.d/elpa/ipython-2927/ipython hides
/home/nbecker/.emacs.d/lisp/ipython

Features:
(shadow sort mail-extr emacsbug sendmail eieio-opt speedbar sb-image
ezimage dframe find-func help-mode misearch multi-isearch diff-mode
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mail-parse rfc2231 rfc2047 rfc2045 ietf-drums mailabbrev mail-utils
gmm-utils mailheader pcvs-util add-log vc warnings vc-dispatcher vc-hg
network-stream auth-source gnus-util mm-util mail-prsvr password-cache
starttls tls jedi-direx direx eieio eieio-core jedi jedi-core
python-environment epc ctable concurrent deferred imenu dired flymake
ido ess-toolbar ess-mouse mouseme browse-url ess-menu ess-swv ess-noweb
ess-noweb-font-lock-mode ess-bugs-l essd-els ess-sas-d ess-sas-l
ess-sas-a ess-sta-d ess-sta-l cc-vars cc-defs make-regexp ess-sp6-d
ess-sp3-d ess-julia ess-r-d ess-r-completion ess-tracebug format-spec
ess-roxy hideshow ess-help ess-developer eldoc ess-s-l ess ess-inf
ess-mode ess-noweb-mode ess-utils ess-custom ess-compat ess-site
auto-complete popup zoom-frm frame-cmds frame-fns avoid browse-kill-ring
edmacro kmacro rst time felineherd byte-opt thingatpt use-package
diminish bytecomp byte-compile cconv bind-key easy-mmode ipython advice
help-fns executable shell pcomplete python-mode info-look cl-macs
compile cl gv cl-loaddefs cl-lib comint ansi-color ring info easymenu
diminish-autoloads package epg-config delsel cus-start cus-load
time-date tooltip electric uniquify ediff-hook vc-hooks lisp-float-type
mwheel x-win x-dnd tool-bar dnd fontset image regexp-opt fringe
tabulated-list newcomment lisp-mode prog-mode register page menu-bar
rfn-eshadow timer select scroll-bar mouse jit-lock font-lock syntax
facemenu font-core frame cham georgian utf-8-lang misc-lang vietnamese
tibetan thai tai-viet lao korean japanese hebrew greek romanian slovak
czech european ethiopic indian cyrillic chinese case-table epa-hook
jka-cmpr-hook help simple abbrev minibuffer 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 make-network-process dbusbind gfilenotify dynamic-setting
system-font-setting font-render-setting move-toolbar gtk x-toolkit x
multi-tty emacs)

Memory information:
((conses 16 248657 26119)
 (symbols 48 35288 16)
 (miscs 40 160 351)
 (strings 32 62111 7050)
 (string-bytes 1 1794555)
 (vectors 16 30112)
 (vector-slots 8 950184 74983)
 (floats 8 170 618)
 (intervals 56 2593 0)
 (buffers 960 28)
 (heap 1024 141858 53739))


-- 
*Those who don't understand recursion are doomed to repeat it*