Edit report at https://bugs.php.net/bug.php?id=55416&edit=1
ID: 55416
Comment by: harvey dot robin at gmail dot com
Reported by: roan dot kattouw at gmail dot com
Summary: array_map() throws PHP warning if the callback
throws an exception
Status: Open
Type: Bug
Package: Arrays related
Operating System: Ubuntu Natty
PHP Version: 5.4.0alpha3
Block user comment: N
Private report: N
New Comment:
I've just come across this too and I'm really surprised at this inconsistent behavior, for
me the question isn't "what kind of situation needs throw a exception in map
function" but "why would the map function behave differently to any other situation".
If you change array_map to array_walk in the original example then the exception propagates upward,
as expected.
At the very least, I'd expect to see a note on the PHP manual page warning users that
exceptions work differently for the callback parameter to array_walk.
Previous Comments:
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[2011-08-16 16:20:17] mah at everybody dot org
http://www.mediawiki.org/wiki/Special:Code/MediaWiki/94433
has Roan's actual use case.
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[2011-08-15 09:35:40] roan dot kattouw at gmail dot com
Basically what I'm doing is
implode("\n", array_map('readStyleFile', $files)
where $files is an array of file names, and readStyleFile() can throw an exception if something is
wrong (in this case it's if the file doesn't exist, but other cases are imaginable). This
exception then propagates up a few levels and is caught and handled. Throwing an exception from
inside the map callback works just fine: it stops the callback, stops array_map(), propagates up to
the caller of array_map(), then works its way up the call stack like any other exception. The only
issue is that warning that won't go away.
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[2011-08-15 08:54:02] laruence@php.net
I was wondering what kind of situation needs throw a exception in map function?
and why doing that? thanks
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[2011-08-13 20:40:11] roan dot kattouw at gmail dot com
Something I forgot to mention in the original report:
Using @array_map(...) suppresses the warning. However, it also suppresses any other notices or
warnings that might happen in the callback. That's why I put the $foo = $bar['baz'];
bit in barf(): if you use @array_map, the "Undefined variable" notice, which is
legitimate, goes away as well.
More generally, @ is kind of a blunt instrument that often suppresses more than you expect it to,
masking mistakes.
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[2011-08-13 20:32:50] roan dot kattouw at gmail dot com
The attached patch fixes this by not throwing the warning if EG(exception) is not NULL. IMO the
warning should be removed completely (because it's superfluous, and I don't see offhand
how it can be triggered other than by an exception, but I don't know PHP core at all), but
it's easy to tweak my patch into doing that instead; this patch is just the minimal solution.
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