Bash does not read up the whole script which it is currently executing

[famzah]

Configuration Information [Automatically generated, do not change]:
Machine: i486
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='i486' 
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='i486-pc-linux-gnu' 
-DCONF_VENDOR='pc' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' -DSHELL 
-DHAVE_CONFIG_H   -I.  -I../bash -I../bash/include -I../bash/lib   -g -O2 -Wall
uname output: Linux famzahpc 2.6.28-14-generic #47-Ubuntu SMP Sat Jul 25 
00:28:35 UTC 2009 i686 GNU/Linux
Machine Type: i486-pc-linux-gnu

Bash Version: 3.2
Patch Level: 48
Release Status: release

Description:
        First I would like to say that I'm not sure if this is a bug or a 
feature of Bash.
        If it is a feature, please let me know how to turn it off; or better 
make it disabled by default...
        
        The problem is that Bash does not read up the whole script which it is 
currently executing.
        As a result of this, if we update the script file with a newer version 
while it is running, this may lead to unpredicted results.

Repeat-By:
        Detailed instructions can be found at 
http://www.famzah.net/bashbug-script-read/
        
        Here is the proof-of-concept scenario:
        1) The script initial version is "old.sh".
        2) I run the script and it executes some commands which take very long 
time to complete (like some "rsync" which transfers a lot of data).
        3) Meanwhile, I update the script with a newer version "new.sh" which 
is no logically different than the initial one. Just a comment is deleted. Here 
is a diff.
        4) The already running "old.sh" script is supposed to finish up, and 
the next new call to it should execute the new "new.sh" version.
        5) However, we end up in a situation where the script, which we 
replaced and was already running, suddenly totally misbehaves.
        6) In our test scenario, the already running "old.sh" script deletes 
our "/home" directory which must never happen, having the Bash scripts' source 
code in mind.

Fix:
        Detailed information can be found at 
http://www.famzah.net/bashbug-script-read/
        
        Proposed solution:
        *) Read up the whole script file in memory, so that we have a 
consistent copy of it, regardless of whether we update the script file during 
the execution. This is how ELF binaries are executed on Linux systems.
        or
        *) If the above is not possible due to performance or other reasons, 
please introduce an option so that we can force Bash to copy the script in 
memory before executing it.