Problem/Motivation

=== NULL vs is_null, which one is better and recommended to use in Drupal core?

In PHP 7 (phpng), is_null is actually marginally faster than ===, although the performance difference between the two is far smaller.

PHP 5.5.9
is_null - float(2.2381200790405)
=== - float(1.0024659633636)
=== faster by ~100ns per call

PHP 7.0.0-dev (built: May 19 2015 10:16:06)
is_null - float(1.4121870994568)
=== - float(1.4577329158783)
is_null faster by ~5ns per call

See https://www.php.net/manual/en/function.is-null.php#117344

Proposed resolution

Remaining tasks

  • Do a benchmark
  • Choose which one to use
  • Replacing

User interface changes

API changes

Data model changes

Release notes snippet

CommentFileSizeAuthor
#7 CheckNullBenchmark.php.txt1.15 KBjungle
#7 result.php7_.3.9.txt11.18 KBjungle
#4 CheckNullBenchmark.php_.txt936 bytesjungle
#4 7.4.2.txt7.7 KBjungle
#4 7.3.39.txt7.71 KBjungle

Comments

jungle created an issue. See original summary.

cilefen’s picture

cilefen commented
Component: php.module » base system
Issue tags: +Performance
init90’s picture

init90
Location Ukraine
commented

+1 to is_null, for me it more readable variant

jungle’s picture

jungle
He/Him
Location Chongqing, China
commented
StatusFileSize
new 7.3.39.txt7.71 KB
new 7.4.2.txt7.7 KB
new CheckNullBenchmark.php_.txt936 bytes

Used phpbench, https://phpbench.readthedocs.io/en/latest/index.html

Command used: 

phpbench  run  CheckNullBenchmark.php --report=default

Reports and the CheckNullBenchmark.php file attached.


Tested against PHP 7.3.9 and 7.4.2. is_null seems slightly better. Or no noticeable difference.

personally, I prefer === NULL, as I prefer === than == when they two are interchangable under a context.

Would vote for won't fix.

jungle’s picture

jungle
He/Him
Location Chongqing, China
commented
Status: Active » Needs review
jungle’s picture

jungle
He/Him
Location Chongqing, China
commented

Or rescope this to replacing is_null($variable) to \is_null($variable)?

See a link @alexpott shared on slack to @catch https://twitter.com/Stof70/status/1251236840876761089 or Null checks are a performance bottleneck of this library #96

jungle’s picture

jungle
He/Him
Location Chongqing, China
commented
StatusFileSize
new result.php7_.3.9.txt11.18 KB
new CheckNullBenchmark.php.txt1.15 KB

No obvious difference from the benchmark, among ===NULL, is_null() and \is_null()

Theoretically, under the namespaced context, \is_null() is better than is_null() probably,

  • to is_null(), looking up function is_null() at the current namespace first, not found, continue and found \is_null(), and executing,
  • to \is_null(), no extra lookup
andypost’s picture

andypost
he/him
Primary language Russian
commented

I bet it expected behaviour of PHP since namespaces started to work - lookup in namespace first and then in global scope

Interesting to check performance impact of prefixing all "global" functions... Better to explore it in separate issue

alexpott’s picture

alexpott
he/they
Primary language English
Location 🇪🇺🌍
commented

This is likely to only have an impact in functions that are called many many times - I don’t think a blanket replace is in order here - but many we could identify any low level global function calls where this is significant.

dqd’s picture

dqd
Location London | N.Y.C | Paris | Hamburg | Berlin
commented

#7 - Look at this and this video (time set to the important point) demonstrating (in another case) how is_array vs \is_array() or is_null() vs. \is_null() can be a huge difference in performance.

init90’s picture

init90
Location Ukraine
commented

Here is a discussion about implementing a fully qualified function in Typo 3: Should we use fully qualified function (FQN) calls like \is_array in the core?

cilefen’s picture

cilefen commented

@init90 I feel like there is such an issue for Drupal but I couldn't find it in a quick search.

catch’s picture

catch
he/him
Primary language English
commented

From one of those links:

Alternatively you can declare all PHP build in function used in the file like:
use function is_array;

This might be a nicer way to do it than \is_array() everywhere.

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smustgrave’s picture

smustgrave commented
Status: Needs review » Needs work

Think it would be nice to maybe have a phpcs check? Should this be a policy idea maybe?

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