> As someone building a framework that uses a container I would very much care > about the distinction between group 2 and group 3.
Larry, this is very valuable feedback. However can you be more specific on when/why? I'm completely open to such an interface if it is actually needed by some code out there. Seeing said code would help, maybe it was mentioned already, I apologize if I missed it. Le 11 novembre 2016 à 19:42:11, Daniel Plainview (daniel.pla...@gmail.com(mailto:daniel.pla...@gmail.com)) a écrit: > > > So why even mention it then? > > I think it's because most implementations are not aware of this difference, > but it's important. > It doesn't automatically mean that the interface must reflect the > DependencyNotFoundException. > @throws FooException means "it's your possible issue, take care of it". > @throws DependencyNotFoundException means "My arm can be broken, take care of > it". > @throws ConfigrationDoesNotExistException means "My leg is broken, take care > of it". > > > As someone building a framework that uses a container I would very much > > care about the distinction between group 2 and group 3 > > Could you, please, provide us a real use-case when you need to catch > DependencyNotFoundException? > > On Friday, November 11, 2016 at 9:19:11 PM UTC+3, Larry Garfield wrote: > > I'm not suggesting converting all exceptions that might possibly happen to > > MisconfiguredServiceException. I'm saying there's 3 broad categories: > > > > 1) What you asked for doesn't exist. > > 2) What you asked for is broken. > > 3) Something else happened, WTF? (Eg, a database-backed container has a > > missing DB.) > > > > I agree that group 3 is out of scope. Group 1 is already covered. The > > question is group 2, where "there is something wrong with the container but > > it's not that what you asked for is missing" is, I assert, legitimately in > > scope. As someone building a framework that uses a container I would very > > much care about the distinction between group 2 and group 3. That doesn't > > mean fully exploring all possible details of group 2 and what might break, > > just indicating the separation between groups 2 and 3. > > > > The current text says, in essence, "for group 2, throw anything but the > > same as group 1". So why even mention it then? And no, that's not a > > suggestion to remove yet more things from the spec. :-) (That way lies more > > incompatibility.) I'm saying there should be a clearly defined exception > > for group 1, a clearly defined parent exception for group 2 (subclasses > > specific to a given implementation entirely welcome), and group 3 is > > not-our-problem. > > > > --Larry Garfield > > > > On 11/07/2016 12:20 PM, Daniel Plainview wrote: > > > The major problem with unchecked exceptions is that it is not class > > > consumer business. > > > What do you say when someone throws SomethingIsBrokenInsideOfMe to you? > > > I'd say "hey, take a vacation, fix yourself, you look unhealthy". Is it > > > not my business what exactly is broken (leg or arm, whatever, it doesn't > > > help to fix my issue). But it is fair enough if library throws > > > YouAreWrong exception in my face when I'm screwed up. > > > > > > When you make a typo in your Container implementation, it could fail with > > > something like \TypeError. It is "unhappy-path", isn't it? Is it > > > MisconfiguredServiceException? I don't think so. What do you do then? You > > > go and fix your implementation. What happens if configuration is broken? > > > You go and fix it as well. I don't see much difference here. > > > > > > MisconfiguredServiceException for me is an illusory solution for > > > "unhappy-path". You can't trust it. What does it exactly mean? What if > > > you make a syntax typo in your PHP configuration (with arrays, let's > > > say), should it raise the MisconfiguredServiceException? Or it should > > > bubble up \ParseError? I mean, it is more like > > > ConfigurationIsTotallyScrewedUp rather than simple MisconfiguredService. > > > It's vague exception that means "something is wrong with *them*". I'd > > > rather catch ALL other (non-NotFoundException) exceptions if I want to > > > avoid program crash for some reason. I can trust \Exception (or even > > > \Throwable). The meaning is simply same: "something is wrong with them" > > > and I don't really care what exactly is. > > > > > > Can you please provide real-life example when you want to catch > > > MisconfiguredServiceException (excepting "I want to log it differently", > > > because it doesn't look real-life, honestly; and it is too universal > > > answer for any kind of exceptions)? > > > > > > On Monday, November 7, 2016 at 5:27:58 PM UTC+3, Larry Garfield wrote: > > > > Container nesting is part of the spec, and a stated goal of the spec, > > > > so it's a valid use case to consider. > > > > > > > > True, there are many different ways that things can break. Consistent > > > > and constructive handling of the not-happy path is a critical part of > > > > spec development. See also: HTML5, the majority of which is not new > > > > stuff but standardizing the many different ways that browsers used to > > > > handle badly formed HTML. It's a total mess because the unhappy path > > > > was never well-defined, so everyone did it differently, so code broke > > > > in a variety of inconsistent ways. My issue is that "throw anything > > > > other than X" is not a consistent and constructive handling of the > > > > non-happy path. > > > > > > > > The biggest distinction I would draw would be between "you asked for > > > > something that's not there" and "you asked for something that's > > > > broken". Those are very different things; one implies I screwed up, the > > > > other implies the configurer screwed up. I can see the argument for not > > > > specifying a separate exception for every possible way that the > > > > requested service is broken (there are many, that's true), but a clear > > > > distinction between those two broad categories ("missing" and "broken") > > > > seems like a much better baseline. > > > > > > > > In that case, I would revise my ask to defining two exceptions: > > > > > > > > * NotFoundException extends ContainerExceptionInterface (thrown if the > > > > requested service isn't defined anywhere) > > > > * MisconfiguredServiceException extends ContainerExceptionInterface > > > > (thrown if the requested service is defined, but for whatever reason > > > > can't be instantiated) > > > > > > > > And implementers are free to subclass the latter if they choose, but > > > > must still have that exception flag on them. (I'm flexible on the name, > > > > the one I have there is likely not the best name.) > > > > > > > > --Larry Garfield > > > > > > > > On 11/05/2016 12:59 PM, Daniel Plainview wrote: > > > > > > A situation of "if your child container throws exception X, you're > > > > > > required to catch it and turn it into anything that's not X but is > > > > > > still Y" seems needlessly convoluted > > > > > > > > > > You did it by introducing "child container", Container contract > > > > > doesn't have any child containers, this contract is very simple and > > > > > straightforward. By saying about child containers, you mean that you > > > > > know how internals of the Container work, you know about "child > > > > > containers", but you shouldn't care about it when you want to use > > > > > Container. > > > > > > > > > > > but doesn't provide me as a developer sufficient debug information. > > > > > > I'd potentially want to log differently depending on which > > > > > > exception it is, but I can't do that if I have no idea what the > > > > > > second exception is going to be; I just know what it's *not* going > > > > > > to be, which means I'd need a Pokemon-catch if I wanted to log it. > > > > > > That's what I am not comfortable with. > > > > > > > > > > I asked you above, what do you think about > > > > > DependencyArgumentTypeMismatchException, > > > > > MissingRequiredArgumentException and many other exceptions, what > > > > > makes them less important than DependencyNotFoundException? They are > > > > > all about wrong configuration (or similar issues that indicates of > > > > > internal problems of Container, not user's failure). > > > > > > > > > > I mean, you can say that "I'd potentially want to log differenty > > > > > DependencyArgumentTypeMismatchException and > > > > > MissingRequiredArgumentException, but I don't know how to catch > > > > > them". There are millions of reasons why container can be broken, > > > > > after all, you can't predict them all. > > > > > > > > > > DependencyNotFoundException is unchecked, because it is not client's > > > > > problem, but internal issue of Container itself. Service does exist, > > > > > but configuration is wrong, client has nothing to do with it, there > > > > > is no sense to reflect it in the interface. > > > > > > > > > > On Saturday, November 5, 2016 at 3:38:06 AM UTC+3, Larry Garfield > > > > > wrote: > > > > > > On 11/04/2016 06:27 AM, David Négrier wrote: > > > > > > > I'll try an analogy with Java. > > > > > > > > > > > > > > In Java, there is a difference between checked and unchecked > > > > > > > exceptions. Checked exceptions are the exceptions that should be > > > > > > > catched by the user. Unchecked exceptions are the exceptions for > > > > > > > which it makes no sense to catch them. There is no reason to > > > > > > > catch an "unchecked exception" because there is no way the user > > > > > > > can provide an interesting alternative behaviour in the catch > > > > > > > statement. So unchecked exception should essentially always > > > > > > > bubble up all the way to the top of the application and trigger > > > > > > > an exception middleware. > > > > > > > > > > > > > > For PSR-11, we deemed that the NotFoundExceptionInterface was a > > > > > > > checked exception (because if the container does not contain the > > > > > > > entry you are looking for, the user can maybe try an alternative > > > > > > > behaviour like looking for an alias or creating a default entry). > > > > > > > We also deemed that the DependencyNotFoundExceptionInterface was > > > > > > > an unchecked exception (because it means the container is poorly > > > > > > > configured and there is little to do about it except display an > > > > > > > error message). > > > > > > > > > > > > > > Finally, we think that checked exceptions should be part of a PSR > > > > > > > while unchecked exceptions should be out of any PSR (because > > > > > > > there is no need to standardize an exception if you don't need to > > > > > > > catch it). > > > > > > > > > > > > > > Of course, there is no absolute truth here. We could decide that > > > > > > > the NotFoundExceptionInterface should be "unchecked" (because you > > > > > > > can always call "has" before "get" so there is no reason this > > > > > > > exception should be catched). Also, since it boils down to "what > > > > > > > valid use case can I have to catch a > > > > > > > DependencyNotFoundExceptionInterface?", we could also find a > > > > > > > valid use case for catching DependencyNotFoundExceptionInterface > > > > > > > and decide it should be part of the PSR. But so far, a quick > > > > > > > survey of frameworks out there has shown that no-one ever catches > > > > > > > the "dependency not found exceptions". > > > > > > > > > > > > > > Also, Larry, you say: > > > > > > > > > > > > > > ... based on the spec alone (no metadoc, no GitHub threads) the > > > > > > > following would be legal: > > > > > > > > > > > > > > try { > > > > > > > $c1->get('a'); > > > > > > > } catch (NotFoundExceptionInterface $e) { > > > > > > > print $e->getMessage(); > > > > > > > // prints "Service 'b' not found" > > > > > > > } > > > > > > > > > > > > > > This is not completely true. The spec states that: > > > > > > > > > > > > > > A call to get can trigger additional calls to get (to fetch the > > > > > > > dependencies). If one of those dependencies is missing, the > > > > > > > NotFoundExceptionInterface triggered by the inner get call SHOULD > > > > > > > NOT bubble out. Instead, it should be wrapped in an exception > > > > > > > implementing the ContainerExceptionInterface that does not > > > > > > > implement the NotFoundExceptionInterface. > > > > > > > > > > > > > > So your code example is only valid if the container decides not > > > > > > > to follow the recommendation (we used "SHOULD NOT" instead of > > > > > > > "MUST NOT" to cope with existing containers). Of course, we could > > > > > > > also strengthen the wording and write: If one of those > > > > > > > dependencies is missing, the NotFoundExceptionInterface triggered > > > > > > > by the inner get call MUST NOT bubble out. > > > > > > > This way, your code sample would be illegal (but it would be > > > > > > > harder for existing containers to implement PSR-11). I have no > > > > > > > strong opinion about the "SHOULD NOT" vs "MUST NOT" idea so far. > > > > > > > Your comments are welcome. > > > > > > > > > > > > > > ++ > > > > > > > David. > > > > > > > > > > > > See, I would disagree with dependency-not-found being an unchecked > > > > > > exception. I think that's the fundamental difference. A situation > > > > > > of "if your child container throws exception X, you're required to > > > > > > catch it and turn it into anything that's not X but is still Y" > > > > > > seems needlessly convoluted, but doesn't provide me as a developer > > > > > > sufficient debug information. I'd potentially want to log > > > > > > differently depending on which exception it is, but I can't do that > > > > > > if I have no idea what the second exception is going to be; I just > > > > > > know what it's *not* going to be, which means I'd need a > > > > > > Pokemon-catch if I wanted to log it. That's what I am not > > > > > > comfortable with. > > > > > > > > > > > > I am generally very skeptical about SHOULD, and favor MUST in > > > > > > nearly all cases by default. SHOULD should be read as "you're > > > > > > allowed to be incompatible here", which is a statement a spec > > > > > > should make as rarely as possible. > > > > > > > > > > > > --Larry Garfield > > > > -- > You received this message because you are subscribed to a topic in the Google > Groups "PHP Framework Interoperability Group" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/php-fig/2pnhudRUpQg/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > php-fig+unsubscr...@googlegroups.com(mailto:php-fig+unsubscr...@googlegroups.com). > To post to this group, send email to > php-fig@googlegroups.com(mailto:php-fig@googlegroups.com). > To view this discussion on the web visit > https://groups.google.com/d/msgid/php-fig/a3502dd2-6319-4072-9c09-0c42af509c71%40googlegroups.com(https://groups.google.com/d/msgid/php-fig/a3502dd2-6319-4072-9c09-0c42af509c71%40googlegroups.com?utm_medium=email&utm_source=footer). > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "PHP Framework Interoperability Group" group. 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