Edit report at https://bugs.php.net/bug.php?id=51882&edit=1
ID: 51882
User updated by: jacob at mediashaker dot com
Reported by: jacob at mediashaker dot com
Summary: Call To Member Function on Non-Object Should Throw
An Exception
Status: Open
Type: Feature/Change Request
Package: *General Issues
Operating System: Centos 5.3
PHP Version: 5.2.13
Block user comment: N
Private report: N
New Comment:
It's simply a general headache. I'm aware of the register_shutdown_function
tricks but unless I've done it wrong, they don't provide a full, accurate
stacktrace. In any case, this is exactly what this proposal is meant to avoid -
created separate error-handling code paths for a common error that does not,
from experience with other dynamic languages, need to be fatal.
In Python I get:
AttributeError: User instance has no attribute 'sayHello'
It's got a full traceback, it's catchable, it has a nicely subclassed error
type. Fatal errors have none of this.
It's a larger issue in cases where you have more complex object object graphs,
in cases where you have references to objects that pass hands frequently. etc.
In an enterprise application with object compositions and complex class
hierarchies, it's not unusual to have situations where you don't have the
object you expect to have. Certainly, this is a bug, but bugs are the reality
of software development and tracing them should be as easy as reasonably
possible.
Unless you have xdebug installed for traceback information, you've got to find
the line of code that initially caused the error and then do something like
`var_dump(debug_backtrace())` to figure out the code path that led to the
error. In a production system with hundreds of deployments, you often can't
simply go around sprinkling debug statements in production code just to get
debug information you could've had for free if the thing were an exception.
If my web app has a nice exception handling mechanism where uncaught errors are
caught by a final, top-level exception handler, where I do things such as
e-mail a sysadmin, or display the error in a pretty-formatted HTML page, these
fatal errors slip through the cracks.
Unless this is a performance decision, or because the development team is
limited by legacy support / backwards compatibility, the behavior simply sucks.
From my POV, this does not need to be as difficult as PHP makes it.
In general, PHP's errors are wonky. Half of them use trigger_error and error
codes, others use exceptions, and finally, there's this big guy which is a
fatal error.
Previous Comments:
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[2011-07-20 15:47:43] binarycleric at gmail dot com
I disagree with changing this from being a fatal error.
Trying to call a method on an object that doesn't exist should always result in
a fatal error because you are
especially calling non-existent code. Trying to call a procedural function that
doesn't exist should result in the
same behavior. I personally wouldn't want anything other than a fatal error to
occur if I tried to call
"some_import_func($herp, $derp);" and it didn't exist, because there is really
no sane way to recover from that. We
have "function_exists" and "method_exists" for a reason.
If you are having constant problems like this with your code then that is
usually a symptom of a larger problem in
how your application is structured. There are hacks and workarounds to get
stacktrace information after a fatal
error using things like "register_shutdown_function", but your code really
shouldn't try to "recover" from a failure
that catastrophic.
I don't mean for this comment to have an "internet toughguy" additude, I'm just
trying to show you that your code
may have more serious problems then you realize. You already have a good
number
of tools in your toolbox, you just
need to learn to use them better.
------------------------------------------------------------------------
[2010-05-21 19:19:32] jacob at mediashaker dot com
Description:
------------
Call to a member function on a non-object is one of the most common reasons a
php script might crash.
Granted, there's often a whole chain of responsibility that falls apart for it
to get to this point.
The problem with this fatal error is that it provides absolutely no debugging
or traceback information when it happens. PHP blows up on fatal errors and all
you're left with is a line number and no idea how it got there.
It would be awesome if it threw an exception with it's requisite traceback
information.
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Edit this bug report at https://bugs.php.net/bug.php?id=51882&edit=1
