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Scream!

PHP

Recently I was debugging some code. That happens. But this code was cluttered with @-operators suppressing error messages. That's annoying. So I wrote a simple extension disabling this operator. That helped.

I then proposed that extension to pecl, while doing that I found out that Gopal has written a similar extension before. After short discussions we added that extension, using the name scream to pecl and released the extension there. Documentation is written and committed and should appear in the PHP documentation within hours.

Posted by Johannes Schlüter in PHP Comments: (9) Trackback: (1)
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PHP-Extension Scream
Die PHP-Extension Scream deaktiviert den @-Operator. Das ist nützlich, um ein Script besser debuggen zu können. Manche Leute kennen wohl nicht die Funktion error_reporting und dekorieren deshalb ihr Script massenhaft mit dem Klammeraffen...
Weblog: Mr. Foo
Tracked: Feb 27, 10:18

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Ian said,

Friday, February 27. 2009 at 00:20 (Link) (Reply)

That's excellent. I'm installing this in my dev environments right now.
HÃ¥vard Eide said,

Friday, February 27. 2009 at 08:12 (Link) (Reply)

Brilliant! Simple, but yet very useful!
Kae Verens said,

Friday, February 27. 2009 at 08:38 (Link) (Reply)

would this not cause problems where the @ is used for expediency?

for example:
[geshi lang=php]$id=(int)@$_REQUEST['id'];[/lang]
where you want an id from GET or POST, or 0 if it's not available.
That, instead of the more verbose
[geshi lang=php]$id=(isset($_REQUEST['id'])?(int)$_REQUEST['id']:0);[/lang]
fa said,

Friday, February 27. 2009 at 13:18 (Link) (Reply)

I don't see the problem here.
I wouldn't use this extension in production code anyway and your approach #1 doesn't look very "expedient" - more unreadable and not "working as intended". Your approach #2 is much cleaner and easily readable anyway.
Giorgio Sironi said,

Friday, February 27. 2009 at 13:24 (Link) (Reply)

Can't you just do:
sed -i -e 's/@//g' `find . | grep php`
(of course @ should be a more complex regex)?
Johannes said,

Friday, February 27. 2009 at 13:45 (Link) (Reply)

As you noted the regexp has to be a bit complexer and I don't want to change the code - I just want to understand why it doesn't work.

Oh and there are valid reasons for the @ - when accessing external resources and doing error handling afterwards. Something along these lines of $fp = @fopen('http://...', 'r'); if (!$fp) { handle_error_nicely(); } - There I won't like my error log having all these errors due to temporary net problems...

So I see this clearly as debugging help for bad code.
Alexandr said,

Tuesday, March 3. 2009 at 02:03 (Link) (Reply)

$fp = @fopen('http://...', 'r'); if (!$fp) { handle_error_nicely(); }

you look for something cleaner and more and easily readable.

why you didn't try

$old_error_reporting_value = error_reporting(0);
$fp = @fopen('http://...', 'r'); if (!$fp) { handle_error_nicely(); }
error_reporting($old_error_reporting_value);

???
Alexandr said,

Tuesday, March 3. 2009 at 02:06 (Link) (Reply)

second code sample need to be without @
like this:

$old_error_reporting_value = error_reporting(0);
$fp = fopen('http://...', 'r'); if (!$fp) { handle_error_nicely(); }
error_reporting($old_error_reporting_value);
Johannes Schlüter said,

Tuesday, March 3. 2009 at 09:13 (Link) (Reply)

This would also disable errors reported while handle_error_nicely() is being called. Yes, this can be fixed bei moving the second error_Reporting call between the fopen and the if but still the @ makes it quite clear which errors are to be ignored.

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