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Posted: Sun Feb 08, 2009 7:18 am

Hi,

is there a way to find uncaught exceptions globally/per method?

Thanks,
Ingmar

Posted: Sun Feb 08, 2009 7:41 am

Exceptions are raised in Run-Time (e.g. while your scripts are running) and you can test your code in order to see if they are properly handled.

Certainly you can statically (without any execution) analyze your scripts in order to find out where the exceptions are generated and where they are caught, but in-general it's very hard to say if all possible combinations are properly handled and no one exception could be left uncaught.

I think it's easier to generate test-cases with adequate code coverage, run them and analyze the results.

Posted: Sun Feb 08, 2009 7:45 am

It's obvious that use cases for automated testing should be applied in order to find all exceptions, but proper IDEs do this on a code analysis level too. I assume PHPED can't do this? If so, is it planned as a feature?

Thanks,
Ingmar

Posted: Sun Feb 08, 2009 8:23 am

no, with dynamic languages like php it's hardly possible to analyze code branches and find the exceptions that aren't properly cautch in particular. Because of php's type-less nature, it's almost always unknown what class instances are stored in the variables. Sometimes it's not even known what methods are called. Just for example:

Code:

function A($cls, $mth, $arg) {
$a = new $cls;
$a->$mth($arg);
}

Posted: Sun Feb 08, 2009 8:32 am

Code:

function A($cls, $mth, $arg) {
$a = new $cls;
$a->$mth($arg);
}

Well, but if it looked like this:

Code:

function A($cls, $mth, $arg) {
if($cls === NULL) { throw new SpecialException('whoopie'); }
$a = new $cls;
$a->$mth($arg);
}

, I should be able to scan my project folder for calls to A() that don't catch SpecialException, shouldn't I? Of course I'm screwed when it comes to things like dynamic method naming, but the exception converage of static code would be of great help. Especially if you could also ask for cases of too general exception handling like

Code:

try {
A();
} catch (Exception $e) {
echo 'Caught Exception: ', $e->getMessage(), "\n";
}

Posted: Sun Feb 08, 2009 9:07 am

Quote:

I should be able to scan my project folder for calls to A() that don't catch SpecialException, shouldn't I?

Well, there are two distinct perspectives, the caller's and the callee's. When you see a particular method, you always know whether it can generate an exception and it's not cautch locally. So you just need to see where this method is called from. It's where you get all the problems with unknown methods/unknown classes. With my example, you can not be sure that method called in the function A is not the method that generates an exception.
Well, even if you know method name, it's not helpful because you need classname too and it's problematic with many PHP code available from many php libraries/frameworks/cms.

Posted: Sun Feb 08, 2009 9:24 am

You are still true about 'your case' that implies dynamic object generation, but if 'my case' would be covered, I'd already be pretty happy. Meaning, that all instances of code that's explicitly calling A(), which do not handle SpecialException, get reported to me.

Posted: Sun Feb 08, 2009 9:40 am

Quote:

Meaning, that all instances of code that's explicitly calling A(), which do not handle SpecialException

ok. What's about all instances of code that call these instances of code calling A()? For example:

Code:

function B() { // does not handle "SpecialException" generated by A
A("foo", "foo", "foo");
}

function C() {
try {
B();
}
catch (SpecialException $e) {
...
}
}

Should B() be found as non-handling SpecialException generated by A?

Posted: Sun Feb 08, 2009 11:35 am

Code:

function B() { // does not handle "SpecialException" generated by A
A("foo", "foo", "foo");
}

function C() {
try {
B();
}
catch (SpecialException $e) {
...
}
}

In this case, no. But in this case, D would be spotted:

Code:

function B() { // does not handle "SpecialException" generated by A
A("foo", "foo", "foo");
}

function C() {
try {
B();
}
catch (SpecialException $e) {
...
}

function D() {
B();
}

The system would have to find any throwing of an Exception and traverse all the way up.

Posted: Sun Feb 08, 2009 12:07 pm

thanks, It's clearer now.