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QaFoo.com:
Never Use null
May 03, 2016 @ 13:07:32

On the QaFoo.com blog they've made a recommendation in their latest post - they suggest that you never use null.

When doing code reviews together with our customers we see a pattern regularly which I consider problematic in multiple regards – the usage of null as a valid property or return value. We can do better than this.

Let's go into common use cases first and then discuss how we can improve the code to make it more resilient against errors and make it simpler to use. Most issues highlighted are especially problematic when others are using your source code. As long as you are the only user (which hopefully is not the case) those patterns might be fine.

They talk about some of the most common uses they see for using null in PHP applications including setters for class properties (injection). They point out that in PHP 7 a missing value on a property would result in a Fatal error and make the functionality harder to test overall. They suggest that all required dependencies be injected on object construction instead, making it easier to know the current state of the object on testing. They also talk some about using null as a return value, how it could make debugging difficult and a solution that could make more sense - throwing an exception instead.

tagged: never use null return value injection setter solution suggestion debugging

Link: https://qafoo.com/blog/083_never_use_null.html

Three Devs & A Maybe:
Episode 92 - Where is the Value? with Joe Watkins
Apr 01, 2016 @ 10:13:42

The Three Devs & a Maybe podcast has published their latest episode, Episode #92 - Where is the Value? with Joe Watkins. This time hosts Michael Budd, Fraser Hart, Lewis Cains and Edd Mann are joined again by Joe Watkins, a core developer on the PHP language.

In this week’s episode we start off discussion with a recent PHP RFC Joe has been working on in-regard to typed properties, bringing up the value (if any) surrounding getters and setters. We then move on to Joe’s views on designing a programming language, and his mind-set that there should be no defined scope surrounding the features that the language should adopt. Finally, we wrap up the show with an update on how stabilisation of uopz is going for PHP 7, along with a reflection on the ‘Hacking on PHP 7’ screencasts we released earlier this month.

You can listen to this latest episode either through the in-page audio player or by downloading the mp3 of the show. You can also subscribe to their feed if you'd like this and other episodes (past and future) delivered right to your client of choice.

tagged: threedevsandamaybe podcast ep92 value joewatkins rfc uopz php7

Link: http://threedevsandamaybe.com/where-is-the-value-with-joe-watkins/

QaFoo:
Testing Effects of Commands With Phake::capture()
Mar 11, 2016 @ 09:15:15

On the QaFoo blog they've posted an article sharing a quick testing tip when using Phake to test APIs where the calls don't return any data.

Today I want to share a simple trick for the excellent Mocking library Phake (I wrote about it before) when testing state on APIs that don't return values.

Testing becomes harder when you are using command / query separation in your code and service operations don't return values anymore. If your command method creates objects and passes them down the stack, then you usually want to make assertions on the nature of the changes.

He gives an example of a class that creates an Order object and saves it but doesn't return a value. He shows how to update this with Phake in the test to capture and verify that the calls are correctly made and the number of products on the order is correct.

tagged: phake capture tutorial example unittest return value

Link: https://qafoo.com/blog/078_phake_capture.html

Johannes Schlüter:
References - Still bad in PHP 7
Feb 19, 2016 @ 09:18:45

Johannes Schlüter has a post to his site that talks about references in PHP 7 and how they're "still bad" based on some of his previous findings.

I'm known for telling "Don't use references" (also as video) as those cause different problems (i.e. with foreach) and hurt performance. The reason for the performance loss is that references disable copy-on-write while most places in PHP assume copy-on-write. Meanwhile we have PHP 7. In PHP 7 the internal variable handling changed a lot among other things the reference counting moved from the zval, the container representing a variable, to the actual element. So I decided to run a little test to verify my performance assumption was still valid.

He includes his testing code that calls a function (strlen) in a loop and compares the handling against two methods, one passing by reference the other not. The results are shown in time taken to execute. He compares the results for PHP 5 and PHP 7, noting that PHP 7 is marginally better when passed by value, by-reference is still about the same.

tagged: reference php7 php5 compare value byreference byvalue test benchmark execution

Link: http://schlueters.de/blog/archives/180-References-Still-bad-in-PHP-7.html

Joshua Thjissen:
Incrementing values in PHP
Oct 13, 2015 @ 10:50:01

Joshua Thjissen has a post to his site looking at a relatively common operation in PHP code - incrementing values - but gets a lot more in-depth than just a simple overview.

Take a variable, increment it with 1. That sounds like a simple enough job right? Well.. from a PHP developer point of view that might seem the case, but is it really? There are bound to be some catches to it (otherwise we wouldn’t write a blogpost about it). So, there are a few different ways to increment a value, and they MIGHT seem similar, they work and behave differently under the hood of PHP, which can lead to – let’s say – interesting results.

He starts with the most basic situations, updating known integer values, but shows the curious things that can happen when the same operations are done on strings. He digs down into the bytecode that's generated from these bits of code, showing the order of operations when the code is actually executed. He then gets into more detail on each kind of operator, starting with the unary increment operator then moving on to the add assignment expression and add operator. For each he describes the behind the scenes bytcode actions happening and where in the PHP source code its being handled (and how).

tagged: increment value integer string bytecode indepth source

Link: https://www.adayinthelifeof.nl/2015/10/13/incrementing-values-in-php/

Bernhard Schussek:
Value Objects in Symfony Forms
Sep 10, 2015 @ 11:35:20

Bernhard Schussek has posted a tutorial on his Webmozart.io site talking about the use of value objects in Symfony forms. By nature value objects don't allow the use of "setters" to assign/change values but he shows how to use a custom data mapper to work around the problem.

Many times, Symfony developers wonder how to make a form work with value objects. For example, think of a Money object with two fields $amount and $currency. [...] Can you write a form type for this class without adding the methods setAmount() and setCurrency()? In this post, I will show you how.

He starts with a bit of an overview on what value objects are and how the concept of immutability comes into play. He shows examples of potential issues if setters are allowed to change data and what should be done when a value change is actually needed. He then gets into the heart of the matter, integrating the forms handling with simple value objects. He goes through building a simple form and the use of the empty_data option to create a new value object with the form values. This works fine but breaks down if you need to update an object. Instead he creates a custom data mapper that sets up two methods, mapDataToForms and mapFormsToData, that allow for both interactions to work correctly.

tagged: value object symfony form tutorial custom data mapper emptydata

Link: https://webmozart.io/blog/2015/09/09/value-objects-in-symfony-forms/

Rob Allen:
ZendInput fallback value
Aug 11, 2015 @ 12:49:26

Rob Allen has posted another article about the ZendInput component of the Zend Framework (he talks about empty values here) this time covering the use of fallback values when the input doesn't contain the needed data.

Recently an issue was reported against ZendInputFilter where the reporter has discovered a regression where the fallback value wasn't being populated correctly. ?Matthew investigated, fixed it and asked me to review it. I was fascinated as I didn't realise (or had completely forgotten!) that ZendInput and ZendInputFilter supported fallback values so I looked into it and it turns out that it's simple and works exactly as its name implies.

He includes a simple example of a fallback for a name value set using the setFallback method on the Input object. He does point out one "wrinkle" in the functionality, however, dependent on the values set for required, allow_empty and continue_if_empty. Certain combinations could make the value either be returned differently than expected or not at all. He includes a small test script that shows the various combinations and what their expected output should look like.

tagged: zendinput fallback value zendframework2 tutorial

Link: http://akrabat.com/zendinput-fallback-value/

Rob Allen:
ZendInput and empty values
Aug 04, 2015 @ 10:49:15

Rob Allen has a post to his site to help clear up some confusion with how the ZendInput component handles "empty" between the required, allow_empty and continue_if_empty logic.

These settings define what happens when you try to validate an empty value for a given input. For ZendInput, empty means exactly equal to null, an empty string or an empty array.

He starts by outlining each of the three settings including both their default settings and its intent. He gets into a bit more detail on continue_if_empty as it has additional logic that depends on the results of the other two settings. He includes a small test application that cycles through a set of values and evaluates them through a ZendInput instance. The output is also included in the post so you can verify your system is seeing the same evaluation results.

tagged: zendinput empty value evaluation required allowempty continueifempty tutorial

Link: http://akrabat.com/zend-input-empty-values/

Freek Lijten:
Value objects
Jul 16, 2015 @ 10:17:14

Freek Lijten has written up a post looking at value objects, how he feels they're not used enough in modern development and a few practical applications of them in action.

I would like to talk about value objects for a bit. Value objects are very underused, very powerful and general good stuff. They might not change your world but they will change, very subtle, a lot of the code you write. I hope to give the shortest possible introduction to the concept and follow up with a couple of example that make me like value objects so much.

He briefly introduces some of the basics of value objects including one of the main points: their immutability. He gives an example of working with a "10 Euro" object, pointing out that once an operation is performed using it, it becomes a different object not just one with a value changed. He also illustrates with an email address example pointing out that email addresses themselves (not the relation to the user) almost never change. He ends the post with another interesting value object scenario using IDs and making them type hint-able.

tagged: value object

Link: http://www.freeklijten.nl/home/2015/07/16/Value-objects

Nikita Popov:
Internal value representation in PHP 7 - Part 2
Jun 22, 2015 @ 10:45:41

Nikita Popov has posted the second part of a series looking at how PHP 7 represents values internally. In the first part of the series the focus was on the major change from PHP 5: the zval updates and how they're allocated. This new post gets into more of the details on each of the types and how they're handled.

In the first part of this article, high level changes in the internal value representation between PHP 5 and PHP 7 were discussed. As a reminder, the main difference was that zvals are no longer individually allocated and don’t store a reference count themselves. Simple values like integers or floats can be stored directly in a zval, while complex values are represented using a pointer to a separate structure.

[...] In the following the details of the individual complex types will be discussed and compared to the previous implementation in PHP 5. One of the complex types are references, which were already covered in the previous part. Another type that will not be covered here are resources, because I don’t consider them to be interesting.

He goes through a few of the different types including strings and arrays and then gets into detail on how objects have changed from PHP 5 to PHP7. He also talks about "indirect zvals" (the IS_INDIRECT handling) that points to another zval instance rather than embedding it. Finally, he talks about two other constants, IS_CONSTANT and IN_CONSTANT_AST, and how they're used behind the scenes with some example code to illustrate.

tagged: internal value variable representation php7 zval types string array object constant ast

Link: http://nikic.github.io/2015/06/19/Internal-value-representation-in-PHP-7-part-2.html