Edit report at https://bugs.php.net/bug.php?id=61747&edit=1
ID: 61747
User updated by: chealer at gmail dot com
Reported by: chealer at gmail dot com
Summary: User-defined error handler run despite at sign (@)
error control operator
Status: Not a bug
Type: Bug
Package: *General Issues
PHP Version: 5.4.0
Block user comment: N
Private report: N
New Comment:
You write:
If you choose to treat @-preceded errors like any other error, that's fine.
Yet http://ca3.php.net/manual/en/language.operators.errorcontrol.php says a
custom error handler should call error_reporting().
So why should a custom error handler which chooses to treat @-preceded errors
like any other error call error_reporting()?
You write:
By default PHP ignores errors from calls preceded by @, but since you are
writing your own you should have the power to override any and all such
defaults.
I'm not sure I would say that custom error handlers *should* have the power to
override error suppression, but I certainly understand that it can be useful.
In any case, offering that flexibility doesn't have to make it more complicated
to write a simple custom handler. set_error_handler() could simply have an
argument to control whether the callback is called even on normally suppressed
errors.
Previous Comments:
------------------------------------------------------------------------
[2012-04-16 22:34:14] [email protected]
I didn't say that I think custom error handlers should ignore suppressed
errors.
I said that the authors of the custom error handlers should decide what to do
with them so they should called error_reporting() and take an appropriate
action. I have seen systems that use the @ to classify something that generates
an E_WARNING as non-critical for example, where an E_WARNING without the @
causes someone to get paged.
And it is documented on the set_error_handler() page. It says:
error_reporting() settings will have no effect and your error handler
will be called regardless - however you are still able to read the
current value of error_reporting and act appropriately. Of particular
note is that this value will be 0 if the statement that caused the
error was prepended by the @ error-control operator.
The point of a custom error handler is to override the default PHP error
handling behaviour. By default PHP ignores errors from calls preceded by @, but
since you are writing your own you should have the power to override any and
all
such defaults. If you choose to treat @-preceded errors like any other error,
that's fine.
This really isn't going to change.
------------------------------------------------------------------------
[2012-04-16 21:50:00] chealer at gmail dot com
I meant it would be inefficient to ask PHP programmers to include
if (!(error_reporting() & $errno)) {
// This error code is not included in error_reporting
return;
}
in all custom error handlers they write, if the problem could be addressed once
and for all by the PHP interpreter.
If that is your stance though, this requirement should be documented in
http://ca3.php.net/manual/en/function.set-error-handler.php
And if you really think that custom error handlers should ignore suppressed
errors, then not calling custom error handlers would be more of a bugfix (for
those handlers that fail to do it) than a BC break. Certainly, that wouldn't be
a "major BC break", although it may be disruptive enough to warrant waiting for
a major release to do such a behavior change.
I'm not saying there's something *wrong* (in the sense of buggy) with the
current implementation, as long as how it works is documented (which wasn't the
case until recently), and the requirement to check for suppressed errors is
documented in set_error_handler()'s documentation (which is still not the case).
------------------------------------------------------------------------
[2012-04-16 21:31:03] [email protected]
There is nothing inefficient about calling error_reporting(). It is a trivially
small and fast internal function. And like I said, changing anything here would
be a major BC break. There is nothing wrong with the current implementation.
------------------------------------------------------------------------
[2012-04-16 21:23:27] chealer at gmail dot com
This is a duplicate of #52338.
Note that I partly disagree with the fix. Custom error handlers *can* check
error_reporting(), as illustrated in the example from
http://ca3.php.net/manual/en/function.set-error-handler.php
function myErrorHandler($errno, $errstr, $errfile, $errline)
{
if (!(error_reporting() & $errno)) {
// This error code is not included in error_reporting
return;
}
[...]
}
However, it would be rather inefficient if custom error handlers *should* (had
to) do that, in general. If that was the case, PHP should simply not call
user-defined error handlers when @ was used.
I think user-defined error handlers *should* do something like that, but only
in some cases.
------------------------------------------------------------------------
[2012-04-16 20:59:18] chealer at gmail dot com
I'm sorry. This was fixed in
http://svn.php.net/viewvc/phpdoc/en/trunk/language/operators.xml?r1=322134&r2=323370
We now have:
When prepended to an expression in PHP, any error messages that might be
generated by that expression will be ignored.
If you have set a custom error handler function with set_error_handler() then
it will still get called, but this custom error handler can (and should) call
error_reporting() which will return 0 when the call that triggered the error
was preceded by an @.
Note that this second sentence contradicts the first in some [edge] cases. At
least, the second sentence should immediately follow the first, rather than
having its own paragraph.
------------------------------------------------------------------------
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