I think we should change the "Function Declarations" in the Coding standards page, so it advises people to use type hinting, when declaring functions that have arrays as arguments.

See more on: http://drupal.org/node/318016

The text could say:

"When the function takes an array as an argument, use type hinting."

And as an example we could use

function my_func(array $foo, $bar) {



jbrown’s picture

Title:Revise the section about "Function Declarations" in the Conding standards page.» Add type hinting to function declaration coding standards
arianek’s picture

Issue tags:-Type Hinting+developer


jhodgdon’s picture

Project:Documentation» Drupal core
Version:» 8.x-dev
Component:Correction/Clarification» documentation
Assigned:johsw» Unassigned
Issue tags:-developer+coding standards

Normally we discuss coding standards in the Drupal Core issue queue, so moving there.

YesCT’s picture

I was looking around the coding standards and also doc standards, and could not find a reference to type hinting. But I thought we did type hinting except for strings.

YesCT’s picture

from conversation with @chx in irc:

We do not type hint primitive types. you can't scalar hint with php
We always hint if we can -- arrays and objects.
But if it can be NULL, we do not type hint because php is ... wont let us.

I've found adding type hints to patches sometimes exposes where the comments in the doc block @param was wrong. That sometimes it whatever or NULL, or it's mixed type, etc.

So type hinting seems to be a good thing.

jhodgdon’s picture

Title:Add type hinting to function declaration coding standards» [policy] Add type hinting to function declaration coding standards

we've been making titles like this for coding standards issues...

jhodgdon’s picture

Project:Drupal core» Drupal Technical Working Group
Component:documentation» Documentation
Issue summary:View changes

Coding standards decisions are now supposed to be made by the TWG

tizzo’s picture

Project:Drupal Technical Working Group» Coding Standards
pfrenssen’s picture

There was already a sniff in the Coder module that was detecting if type hints were missing, but in #2560651: PHP_Codesniffer flagging 'Type hint "array" missing...' but type hints not a standard this sniff was removed with the argument that the coding standards do not require it.

I think omitting this type hint is not only a bad practice from a coding standards point of view but an actual bug, so I am 100% in favour of this being added to the standard.

pfrenssen’s picture

drunken monkey’s picture

Title:[policy] Add type hinting to function declaration coding standards» Add type hinting to function declaration coding standards

Also very much in favor of this! I think it's already more or less an unspoken law to use type hinting, and it does make a lot of sense – we should just make it official.

But if it can be NULL, we do not type hint because php is ... wont let us.

Luckily, this is not true (anymore?) – by just setting NULL as the default value for the parameter, you can add an "or NULL" option to your type hint.

PS: Since there is now an entire queue just for coding standards, I think the "[policy]" prefix isn't needed anymore?
And maybe we should use category "Plan" now, or define our own system for the categories?

pfrenssen’s picture

Proposed update for the Function declaration section in the main coding standard page. The code example is updated as well as the sentence in bold text.

function funstuff_get_animal(HerdInterface $herd, array $options = array()) {
  $name = !empty($options['animal_name']) ? $options['animal_name'] : 'Fido';
  return $herd->getAnimal($name);

Arguments with default values go at the end of the argument list. Always use type hints when possible. Always attempt to return a meaningful value from a function if one is appropriate.

Proposed update for the Type hinting section in the coding standards for object oriented code. Adding the sentence in bold text:

PHP supports optional type specification for function and method parameters for classes and arrays. Although called "type hinting" it does make a type required, as passing an object a parameter that does not conform to that type will result in a fatal error.

  • DO specify a type hint for arrays, and when conformity to a specific interface is an assumption made by the function or method. Specifying the required interface makes debugging easier as passing in a bad value will give a more useful error message.
  • DO NOT use a class as the type in type hinting. If specifying a type, always specify an Interface. That allows other developers to provide their own implementations if necessary without modifying existing code.