Skip to content

Nothing is lower than null and object is never equal to null #4131

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Jul 21, 2025
+96 −5
Merged

Nothing is lower than null and object is never equal to null #4131

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
8 changes: 8 additions & 0 deletions src/Type/NullType.php
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -110,6 +110,10 @@ public function isSmallerThan(Type $otherType, PhpVersion $phpVersion): TrinaryL
return $otherType->isGreaterThan($this, $phpVersion);
}

if ($otherType->isObject()->yes()) {
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The PR title says "Nothing is lower than null" but this change sounds to me like the opposite.

The method asks "is null smaller than object?" and you return "yes".

Maybe I'm running on fumes with only half the brain but I'd like this to be explained. Thanks.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

My bad, I missed some explanation.

Nothing is lower then null so
null <= $anything is always true
$anything < null is always false

And an object cannot be equal to null so
null < $object is always true
$object <= null is always false

return TrinaryLogic::createYes();
}

return TrinaryLogic::createMaybe();
}

Expand All @@ -123,6 +127,10 @@ public function isSmallerThanOrEqual(Type $otherType, PhpVersion $phpVersion): T
return $otherType->isGreaterThanOrEqual($this, $phpVersion);
}

if ($otherType->isObject()->yes()) {
return TrinaryLogic::createYes();
}

return TrinaryLogic::createMaybe();
}

Expand Down
8 changes: 8 additions & 0 deletions src/Type/Traits/UndecidedComparisonCompoundTypeTrait.php
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -13,11 +13,19 @@ trait UndecidedComparisonCompoundTypeTrait

public function isGreaterThan(Type $otherType, PhpVersion $phpVersion): TrinaryLogic
{
if ($otherType->isNull()->yes() && $this->isObject()->yes()) {
Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This add some logic in the trait but I didn't find another way except creating an ObjectComparisonCompoundTypeTrait and an ObjectComparisonTypeTrait.

Do you prefer to create two new traits ?

return TrinaryLogic::createYes();
}

return TrinaryLogic::createMaybe();
}

public function isGreaterThanOrEqual(Type $otherType, PhpVersion $phpVersion): TrinaryLogic
{
if ($otherType->isNull()->yes()) {
return TrinaryLogic::createYes();
}

return TrinaryLogic::createMaybe();
}

Expand Down
15 changes: 14 additions & 1 deletion src/Type/Traits/UndecidedComparisonTypeTrait.php
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -5,18 +5,27 @@
use PHPStan\Php\PhpVersion;
use PHPStan\TrinaryLogic;
use PHPStan\Type\MixedType;
use PHPStan\Type\NullType;
use PHPStan\Type\Type;

trait UndecidedComparisonTypeTrait
{

public function isSmallerThan(Type $otherType, PhpVersion $phpVersion): TrinaryLogic
{
if ($otherType->isNull()->yes()) {
return TrinaryLogic::createNo();
}

return TrinaryLogic::createMaybe();
}

public function isSmallerThanOrEqual(Type $otherType, PhpVersion $phpVersion): TrinaryLogic
{
if ($otherType->isNull()->yes() && $this->isObject()->yes()) {
return TrinaryLogic::createNo();
}

return TrinaryLogic::createMaybe();
}

Expand All @@ -32,11 +41,15 @@ public function getSmallerOrEqualType(PhpVersion $phpVersion): Type

public function getGreaterType(PhpVersion $phpVersion): Type
{
return new MixedType();
return new MixedType(subtractedType: new NullType());
}

public function getGreaterOrEqualType(PhpVersion $phpVersion): Type
{
if ($this->isObject()->yes()) {
return new MixedType(subtractedType: new NullType());
}

return new MixedType();
}

Expand Down
8 changes: 4 additions & 4 deletions tests/PHPStan/Analyser/nsrt/bcmath-number.php
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -190,10 +190,10 @@ public function bcVsNull(Number $a): void
assertType('*ERROR*', $a ** $b);
assertType('*ERROR*', $a << $b);
assertType('*ERROR*', $a >> $b);
assertType('bool', $a < $b);
assertType('bool', $a <= $b);
assertType('bool', $a > $b);
assertType('bool', $a >= $b);
assertType('false', $a < $b);
assertType('false', $a <= $b);
assertType('true', $a > $b);
assertType('true', $a >= $b);
assertType('int<-1, 1>', $a <=> $b);
assertType('bool', $a == $b);
assertType('bool', $a != $b);
Expand Down
20 changes: 20 additions & 0 deletions tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3588,6 +3588,26 @@ public function testBug13171(): void
]);
}

public function testBug10719(): void
{
$this->checkThisOnly = false;
$this->checkNullables = true;
$this->checkUnionTypes = true;
$this->checkExplicitMixed = true;

$this->analyse([__DIR__ . '/data/bug-10719.php'], []);
}

public function testBug9141(): void
{
$this->checkThisOnly = false;
$this->checkNullables = true;
$this->checkUnionTypes = true;
$this->checkExplicitMixed = true;

$this->analyse([__DIR__ . '/data/bug-9141.php'], []);
}

public function testBug3396(): void
{
$this->checkThisOnly = false;
Expand Down
16 changes: 16 additions & 0 deletions tests/PHPStan/Rules/Methods/data/bug-10719.php
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,16 @@
<?php declare(strict_types = 1);

namespace Bug10719;

use DateTime;

$dt1 = null;
$dt2 = new DateTime();

if (rand(0, 1)) {
$dt1 = (clone $dt2)->setTimestamp($dt2->getTimestamp() + 1000);
}

if ($dt1 > $dt2) {
echo $dt1->getTimestamp();
}
26 changes: 26 additions & 0 deletions tests/PHPStan/Rules/Methods/data/bug-9141.php
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,26 @@
<?php declare(strict_types = 1);

namespace Bug9141;

use DateTimeImmutable;

class HelloWorld
{

private ?DateTimeImmutable $startTime;

public function __construct() {
$this->startTime = new DateTimeImmutable();
}

public function getStartTime(): ?DateTimeImmutable
{
return $this->startTime;
}

}

$helloWorld = new HelloWorld();
if ($helloWorld->getStartTime() > new DateTimeImmutable()) {
echo sprintf('%s', $helloWorld->getStartTime()->format('d.m.y.'));
}
Loading