Should a function return null?
E.g.
function test()
{
return null; // vs return;
}
Is the latter considered bad practice or doesn’t it matter?
PS
Whether it is bad practice shouldn’t be subjective IMHO.
If you don’t return anything, just use return; or omit it at all at the end of the function.
If your function is usually returns something but doesn’t for some reason, return null; is the way to go.
That’s similar to how you do it e.g. in C: If your function doesn’t return things, it’s void, otherwise it often return either a valid pointer or NULL.
Answer：
Always is a good practice to show what you’re returning.
But as a tip, the following are all equivalent:
function test()
{
return null;
}
function test()
{
return;
}
function test()
{
}
In all cases there for var_dump(test()); will be:
NULL
Answer：
An undefined function return value in PHP always equals NULL, so it does not make any difference (the runtime does this).
What makes a difference is that you make use of docblocks and document the return value with the @return tag so clever IDE’s offer info here.
If you want to signal per the docblock that not-returning a value is intended, you can use void:
* @return void
If you want to signal that returning NULL is intended, you can use null or NULL (depending on your code-style for uppercase PHP standard constants):
* @return null
or:
* @return NULL
That should make the coders intention visible as by PHP this is would be always null as the factual return value.
Read on:
More details and updated information is in PeeHaa’s answer to this same question.
Answer：
It is just plain silly to return null if there is nothing to return. Doing return; shows intend of not actually returning anything. And makes it clear what the function does.
The fact that PHP does not have a void return type yet should not be a reason to make the intend less clear. Also note that PHP 7.1 will provide support for the void return type:
function test(): void {
return null; // this will error
}
Answer：
When you use return type declarations with the nullable prefix “?” there is a difference!
The PHP documentation says …
As of PHP 7.1.0, return values can be marked as nullable by prefixing the type name with a question mark (?). This signifies that the function returns either the specified type or NULL.
So, when you return nothing the error message will be:
Fatal error: Uncaught TypeError: Return value of test() must be of the type string or null, none returned in ...
And when you return return; the error message will be:
Fatal error: A function with return type must return a value (did you mean "return null;" instead of "return;"?) in ...
When you return null, everything is fine.
Answer：
Semantically, I don’t think there’s a difference between the two. According to the PHP documentation on return:
If no parameter is supplied, then the parentheses must be omitted and
NULL will be returned.
I personally like putting the NULL there. Then there’s no question as to what’s being returned, making your debugging a little easier.
Answer：
The PEAR best practices page does a return null in their “Return early” example. This increases readability which we should always try to do since we write code for humans, not computers.
source: http://pear.php.net/manual/en/standards.bestpractices.php
