----- Ursprüngliche Message -----
> Von: Charles Sprayberry <cspray....@gmail.com> > An: "internals@lists.php.net" <internals@lists.php.net> > CC: > Gesendet: 1:56 Dienstag, 5.Februar 2013 > Betreff: [PHP-DEV] SplFileObject::__toString potentially returns false > >T here was a previous discussion on the return value of > SplFileObject::__toString being > an alias to SplFileObject::current() but that was about the design decision > why and not > really suggesting any kind of change or a technical error. In the > discussion it was > established that: > > (1) Changing this would be a BC break > (2) It isn't really a bug in the codebase, the docs were just wrong > > The current implementation has a bug in that current() can potentially > return false, if > false is returned from the __toString() magic method a catchable fatal > error occurs. > [...] > I would say that SplFileObject:__toString() being an alias to > SplFileObject::current() > makes the use cases for the method very limited and that the current > implementation is > mistaken in returning current(). I can think of no use case where > SplFileObject::__toString() > should return this value. If need to get the current line you're probably > iterating and in > that case should be using foreach() and don't really need to manually take > care of that. > Even if there is a use case for manually invoking > `SplFileObject::current()` you probably > aren't casting a string in that situation and a more expressive method call > is better. > > (1) Leave the implementation the way it is and simply return a blank string > when > current() would return false > > (2) Change the implementation to return SplFileInfo::__toString() > > (3) Change the implementation to return entire file contents > > (4) Return some other unthought of string but remains consistent and logical > > I am personally partial to (2) or (3) perhaps in 5.5 but (1) could probably > happen > sooner? Thoughts? > I often use this object. A few things I can notice: - In practice I never ran over this error. Mainly because I use `foreach` rather than the object itself in string context to obtain the line(s). - Even I did not run into a concrete problem, I would consider this a bug because the object itself is violating the __toString() interface. When I get that error with my own code, I always consider this a bug and fix it. So this should be fixed in PHP core code when I keep myself as a mark. - Because SplFileObject is a subtype of SplFileInfo, it should return the same for the same interface, e.g. `__toString()` must return the same type of value as of SplFileInfo to not break the substitution. Only the more specific parts of the interface are allowed to offer more specific behavior. Right now it violates LSP. This should be addressed and fixed behaving exactly like SplFileInfo. IMHO fixing all these flaws require a BC break which I would consider something good in this specific case. So I welcome a BC break as soon as possible so that in the future functions accepting a SplFileInfo also work with SplFileObjects if they make use of the string context. Until then, a workaround is to provide your own subclass of SplFileObject that overwrites `__toString()` again. Maybe this is something useful for projects that make use of the SplFileObject already. -- hakre -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
