Even easier to reproduce:

<?php var_dump(exec("echo ' '")); ?>

My suggestion:

http://ecl.zoone.com.br/etc/patches/bug43908.patch

In your patch it appears that you are still deliberately removing whitespace. Why?

The actual implementation strip trailing whitespaces, my patch also do it, but when the string contains only whitespaces, it remove just \r and \n.

> The actual implementation strip trailing whitespaces, my patch also do
> it, but when the string contains only whitespaces, it remove just \r
> and \n.

So why are you explicitly fixing only half of the bug and leaving the other half in?

Because that is intentional, however, it affect results as your case, when the string is consisting entirely of whitespace.

Well, anyway, maybe this isn't a good idea, it was only my idea.

Could we have this fix in the next version please? Just remove all the code that removes the whitespace?

Expected behaviour and can not be changed. RTFM: http://php.net/exec

This is most certainly not expected behaviour, and furthermore, it is dataloss.

If you must preserve backwards compatibility, which is certainly fair, then I recommend you add a new boolean option to the exec() call to preserve the whitespace. Either way, this bug is not bogus.

I have an application whose output may or may not contain lines that contain only whitespace. I need for this whitespace to be preserved as otherwise I cannot parse the output correctly.

Please note that I'm not talking about the trailing "\n" which is mentioned in the documentation. I'm referring to all other whitespace, especially spaces and tabs.

Reclassified.

I've just run into this "feature", writing a tool that needs to be able to read in a file from a given commit repo.  Because of the "feature", every line in the resulting file is stripped of trailing whitespace, creating a lot of spurious diffs.

I am at a loss to see the motivation for this behavior.  Information is being discarded, with no possibility of recovering it.  The only workaround I can think of is to
1. Use sed, or a comparable utility, to add a non-whitespace character to the end of every line
2. Make the PHP exec() call
3. In PHP, strip the spurious character from the end of each line.

Please put in the extra flag to turn this behavior off.

If you want the raw unaltered output from the command use shell_exec() not 
exec(). By definition exec() has to use a delimiter in order to create the array. 
If you don't want it to do that, just grab the raw via shell_exec() and do your 
own parsing.

If I use shell_exec(), is there any way to get the exit code?

With regard to the need for a delimiter, I guess that, like Arne, I'm wondering why we couldn't just use the newline character for that purpose.

If you want full control, use proc_open/proc_close. proc_close() will give you 
the exit code or you can write $? to one of the streams to get a more accurate 
one. I suppose you could also do something intelligent with $? on the 
shell_exec() command, but that is more of a hack. All these exec() functions 
simply apply different levels of filtering and usability on top of the low-level 
proc_open() call. If it isn't doing what you want drop down a level and implement 
what you need. There are plenty of cases where you want \r\n and all other 
whitespace stripped from the end of lines.