Hello !
In PHP 5.4 alpha, an exception is throwing if a subclass of
\DirectoryIterator not called the parent constructor.
Moreover, this exception can not be catched in the constructor of the
subclass.
This behavious seems to be a good idea, because \DirectoryIterator may
be in an inconsistant state if the parent constructor is not called.
But i think that it's not a good idea, because it's a BC break.
It's not the case in 5.3 and i have unit test cases which fail by this
new behavior, because moked \DirectoryIterator class does not call the
parent constructor.
In context of unit test, the fact that \DirectoryIterator is
inconsistant may be not a problem and can be the desired behavior.
There is a bug report : https://bugs.php.net/bug.php?id=55300
Best regards,
Fred
========================================================================
Frédéric Hardy : Architecte d'application/Admin. système/Ergonome
CV : http://blog.mageekbox.net/public/cv.frederic.hardy.pdf
Blog : http://blog.mageekbox.net
Twitter : http://twitter.com/mageekguy
Hello,
2011/7/28 Frédéric Hardy frederic.hardy@mageekbox.net:
Hello !
In PHP 5.4 alpha, an exception is throwing if a subclass of
\DirectoryIterator not called the parent constructor.
Moreover, this exception can not be catched in the constructor of the
subclass.
This behavious seems to be a good idea, because \DirectoryIterator may be in
an inconsistant state if the parent constructor is not called.
But i think that it's not a good idea, because it's a BC break.
It's not the case in 5.3 and i have unit test cases which fail by this new
behavior, because moked \DirectoryIterator class does not call the parent
constructor.
In context of unit test, the fact that \DirectoryIterator is inconsistant
may be not a problem and can be the desired behavior.
We have two ways internally of execute code that needs to be executed
as soon as we instantiate the object:
- In the constructor
- In the handler managing instantiation.
Doing it in (1) is problematic as PHP gives no implicit guarantee that
it will be called. Doing it in (2) is also problematic as it makes the
class "magic", by putting code with effects in a place where it
doesn't belong.
From a design perspective it is better to execute such code in the
constructor, especially if it takes argument, so (1) is "more correct"
than (2).
Now, as I said, PHP does not force you to call the parent constructor.
In almost every cases, not calling the overridden constructor is bad
practice and yields inconsistent results.
For internal classes, skipping code that often do mostly
initialization is dangerous and leads to crashes.
Now, for the issue at hand:
Even though it is a BC break, I believe that it is a very small one
and that it should be seen as a bug fix.
Note that the restriction is only here if the user tries to do
something terribly wrong.
IMO, it should remain impossible to extend DirectoryIterator's
__construct without calling the parent construct.
Best,
There is a bug report : https://bugs.php.net/bug.php?id=55300
Best regards,
Fred========================================================================
Frédéric Hardy : Architecte d'application/Admin. système/Ergonome
CV : http://blog.mageekbox.net/public/cv.frederic.hardy.pdf
Blog : http://blog.mageekbox.net
Twitter : http://twitter.com/mageekguy--
--
Etienne Kneuss
http://www.colder.ch
2011/7/28 Frédéric Hardy frederic.hardy@mageekbox.net:
Hello !
In PHP 5.4 alpha, an exception is throwing if a subclass of
\DirectoryIterator not called the parent constructor.
Moreover, this exception can not be catched in the constructor of the
subclass.
This behavious seems to be a good idea, because \DirectoryIterator may be in
an inconsistant state if the parent constructor is not called.
But i think that it's not a good idea, because it's a BC break.
It's not the case in 5.3 and i have unit test cases which fail by this new
behavior, because moked \DirectoryIterator class does not call the parent
constructor.
In context of unit test, the fact that \DirectoryIterator is inconsistant
may be not a problem and can be the desired behavior.
I strongly agree. Throwing an exception ONLY because the parent constructor wasn't called is a serious departure from expectations. It is fine for other code in the parent class to fail later due to incomplete/improper initialization which may likely be caused by failure to call the parent constructor earlier, (In fact, that is even expected in many cases) but I cannot conceive of any acceptable reason for the error described here. Even though the change was certainly well intentioned, it clearly didn't account for the possibility of unusual but valid coding situations (such as mocks and other code generation tactics that should be able to reasonably depend on consistent language behaviors).
John Crenshaw
Priacta, Inc.
2011/7/28 Frédéric Hardy frederic.hardy@mageekbox.net:
Hello !
In PHP 5.4 alpha, an exception is throwing if a subclass of
\DirectoryIterator not called the parent constructor.
Moreover, this exception can not be catched in the constructor of the
subclass.
This behavious seems to be a good idea, because \DirectoryIterator may be in
an inconsistant state if the parent constructor is not called.
But i think that it's not a good idea, because it's a BC break.
It's not the case in 5.3 and i have unit test cases which fail by this new
behavior, because moked \DirectoryIterator class does not call the parent
constructor.
In context of unit test, the fact that \DirectoryIterator is inconsistant
may be not a problem and can be the desired behavior.I strongly agree. Throwing an exception ONLY because the parent constructor wasn't called is a serious departure from expectations. It is fine for other code in the parent class to fail later due to incomplete/improper initialization which may likely be caused by failure to call the parent constructor earlier, (In fact, that is even expected in many cases) but I cannot conceive of any acceptable reason for the error described here. Even though the change was certainly well intentioned, it clearly didn't account for the possibility of unusual but valid coding situations (such as mocks and other code generation tactics that should be able to reasonably depend on consistent language behaviors).
If the constructor MUST be called, then it would seem that you must
not be allowed to extend it and instead, have another method which you
must use.
Badly, beforeConstruct() and/or afterConstruct(), but then we are
moving to AOP (which would be nice).
Enforcement of the constructor can only be achieved by making it final.
Richard Quadling
Twitter : EE : Zend : PHPDoc
@RQuadling : e-e.com/M_248814.html : bit.ly/9O8vFY : bit.ly/lFnVea