stat(1) returns outdated info

Hi,

I've written a little script that gives me a message upon login in case of pending commit in my local git repository.

It worked OK until I upgraded to 14.04.1: Then, it started to show false positive.

In the end, I tracked the problem to be related with stat(1) returning outdated information (See hereunder for more details).

Does anyone has a clue of why stat(1) returns outdated info?

Best regards,

Cyrille

=======================================

Technical details:
==============

The script is placed in the /etc/update-mot-d.d/ folder and does the following:

if [ -d /etc/.git ];then
  cd /etc
  diff=$(sudo git status --porcelain);
  if [ -n "$diff" ];then
    echo
    echo '!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!'
    echo
    echo 'WARNING: There are uncommited changes in the /etc directory!'
    echo
    echo ' Please run "cd /etc;git status" to figure out what is going on.'
    echo
    echo '!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!'
  fi
fi

Now, as I said, it started to return false positive after the upgrade to Ubuntu 14.04.1. For example, yesterday, I've created a file /etc/test during a few hours and then deleted it and today I've had a false positive against this file (It's quite easily reproductible).

Hopefully, I'd changed my script to give me more information:

if [ -d /etc/.git ];then
  cd /etc
  diff=$(sudo git status --porcelain);
  if [ -n "$diff" ];then
    echo
    echo '!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!'
    echo
    echo 'WARNING: There are uncommited changes in the /etc directory!'
    echo
    echo ' Please run "cd /etc;git status" to figure out what is going on.'

echo "$diff"
f=$(echo $diff | cut -f 2 -d " " -)
git ls-files --debug $f
stat --format "%n %Y %Z %s" $f
    echo
    echo '!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!'
  fi
fi

And, the result was this:

login as: support
support@xxx's password:
Welcome to Ubuntu 14.04.1 LTS (GNU/Linux 3.13.0-37-generic x86_64)

 * Documentation: https://help.ubuntu.com/

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

WARNING: There are uncommited changes in the /etc directory!

    Please run "cd /etc;git status" to figure out what is going on.
?? test
test 1414588482 1414588482 0

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

  System information as of Wed Oct 29 14:54:19 CET 2014

  System load: 0.28 Processes: 153
  Usage of /: 4.6% of 45.71GB Users logged in: 1
  Memory usage: 1% IP address for p1p1: a.b.c.d
  Swap usage: 0%

  Graph this data and manage this system at:
    https://landscape.canonical.com/

16 packages can be updated.
16 updates are security updates.

Last login: Wed Oct 29 14:54:19 2014 from 2001::
support@xxx:~$ stat /etc/test
stat: cannot stat ‘/etc/test’: No such file or directory
support@xxx:~$

See how stat(1) returns outdated information during the motd?