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Fix "ob_get_*() === false will always evaluate to false" false positive #6097

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Merged
staabm merged 4 commits into from
Jul 24, 2026
Merged

Fix "ob_get_*() === false will always evaluate to false" false positive #6097

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83d0eaf
Fix "ob_get_*() === false will always evaluate to false" false positive
staabm Jul 24, 2026
1cd15a8
cs
staabm Jul 24, 2026
0f4bf66
Update output-buffering.php
staabm Jul 24, 2026
7a6b35b
Update OutputBufferingDynamicReturnTypeExtension.php
staabm Jul 24, 2026
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8 changes: 5 additions & 3 deletions src/Type/Php/OutputBufferingDynamicReturnTypeExtension.php
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Original file line number Diff line number Diff line change
Expand Up @@ -8,11 +8,10 @@
use PHPStan\DependencyInjection\AutowiredService;
use PHPStan\Reflection\FunctionReflection;
use PHPStan\Reflection\ParametersAcceptorSelector;
use PHPStan\Type\Constant\ConstantBooleanType;
use PHPStan\Type\DynamicFunctionReturnTypeExtension;
use PHPStan\Type\IntegerRangeType;
use PHPStan\Type\Type;
use PHPStan\Type\TypeCombinator;
use PHPStan\Type\TypeUtils;
use function in_array;

/**
Expand Down Expand Up @@ -48,7 +47,10 @@ public function getTypeFromFunctionCall(

$outputBufferLevelType = $scope->getType(new FuncCall(new Name('ob_get_level'), []));
if (IntegerRangeType::createAllGreaterThanOrEqualTo(1)->isSuperTypeOf($outputBufferLevelType)->yes()) {
return TypeCombinator::remove($defaultReturnType, new ConstantBooleanType(false));
// checking error state return values of ob_* functions is essentially useless
// as this usually means that your system is out of memory and your process is going to die anyway.
// that's why error states oftentimes are not checked.
return TypeUtils::toBenevolentUnion($defaultReturnType);
}

return $defaultReturnType;
Expand Down
52 changes: 26 additions & 26 deletions tests/PHPStan/Analyser/nsrt/output-buffering.php
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Original file line number Diff line number Diff line change
Expand Up @@ -17,8 +17,8 @@ function activeBuffer(): void
{
ob_start();
assertType('int<1, max>', ob_get_level());
assertType('string', ob_get_contents());
assertType('int', ob_get_length());
assertType('(string|false)', ob_get_contents());
assertType('(int|false)', ob_get_length());
}

function obCleanAndFlushKeepBuffer(): void
Expand All @@ -27,17 +27,17 @@ function obCleanAndFlushKeepBuffer(): void
assertType('int<1, max>', ob_get_level());
ob_clean();
assertType('int<1, max>', ob_get_level());
assertType('string', ob_get_contents());
assertType('(string|false)', ob_get_contents());
ob_flush();
assertType('int<1, max>', ob_get_level());
assertType('string', ob_get_contents());
assertType('(string|false)', ob_get_contents());
}

function getCleanClosesBuffer(): void
{
ob_start();
assertType('int<1, max>', ob_get_level());
assertType('string', ob_get_clean());
assertType('(string|false)', ob_get_clean());
assertType('int<0, max>', ob_get_level());
assertType('string|false', ob_get_contents());
}
Expand All @@ -46,7 +46,7 @@ function getFlushClosesBuffer(): void
{
ob_start();
assertType('int<1, max>', ob_get_level());
assertType('string', ob_get_flush());
assertType('(string|false)', ob_get_flush());
assertType('int<0, max>', ob_get_level());
assertType('string|false', ob_get_contents());
}
Expand All @@ -55,7 +55,7 @@ function endCleanClosesBuffer(): void
{
ob_start();
assertType('int<1, max>', ob_get_level());
assertType('string', ob_get_contents());
assertType('(string|false)', ob_get_contents());
ob_end_clean();
assertType('int<0, max>', ob_get_level());
assertType('string|false', ob_get_contents());
Expand All @@ -65,7 +65,7 @@ function endFlushClosesBuffer(): void
{
ob_start();
assertType('int<1, max>', ob_get_level());
assertType('string', ob_get_contents());
assertType('(string|false)', ob_get_contents());
ob_end_flush();
assertType('int<0, max>', ob_get_level());
assertType('string|false', ob_get_contents());
Expand All @@ -77,10 +77,10 @@ function nested(): void
assertType('int<1, max>', ob_get_level());
ob_start();
assertType('int<2, max>', ob_get_level());
assertType('string', ob_get_contents());
assertType('(string|false)', ob_get_contents());
ob_end_clean();
assertType('int<1, max>', ob_get_level());
assertType('string', ob_get_contents());
assertType('(string|false)', ob_get_contents());
ob_end_clean();
assertType('int<0, max>', ob_get_level());
assertType('string|false', ob_get_contents());
Expand All @@ -99,15 +99,15 @@ function fullyQualified(): void
{
\ob_start();
assertType('int<1, max>', ob_get_level());
assertType('string', \ob_get_contents());
assertType('string', ob_get_contents());
assertType('(string|false)', \ob_get_contents());
assertType('(string|false)', ob_get_contents());
}

function levelNarrowedToConstInt(): void
{
if (ob_get_level() === 2) {
assertType('2', ob_get_level());
assertType('string', ob_get_clean());
assertType('(string|false)', ob_get_clean());
// closing call decrements the const-int level, keeping it exact
assertType('1', ob_get_level());
}
Expand All @@ -123,18 +123,18 @@ function levelNarrowedToIntRange(): void
{
if (ob_get_level() >= 1) {
assertType('int<1, max>', ob_get_level());
assertType('string', ob_get_clean());
assertType('(string|false)', ob_get_clean());
}
}

function levelNarrowedToUnionInt(): void
{
if (ob_get_level() === 1 || ob_get_level() === 3) {
assertType('1|3', ob_get_level());
assertType('string', ob_get_contents());
assertType('(string|false)', ob_get_contents());
ob_start();
assertType('2|4', ob_get_level());
assertType('string', ob_get_contents());
assertType('(string|false)', ob_get_contents());
}
}

Expand All @@ -150,7 +150,7 @@ function levelNarrowedToBoundedIntRange(): void
{
if (ob_get_level() >= 2 && ob_get_level() <= 5) {
assertType('int<2, 5>', ob_get_level());
assertType('string', ob_get_clean());
assertType('(string|false)', ob_get_clean());
// closing call shifts the whole range down, preserving the upper bound
assertType('int<1, 4>', ob_get_level());
}
Expand Down Expand Up @@ -180,7 +180,7 @@ function pureCallableKeepsLevel(callable $cb): void
ob_start();
$cb();
assertType('int<1, max>', ob_get_level());
assertType('string', ob_get_clean());
assertType('(string|false)', ob_get_clean());
}

function impureFunctionForgetsLevel(): void
Expand All @@ -206,7 +206,7 @@ function pureFunctionKeepsLevel(): void
ob_start();
$x=pureFunction();
assertType('int<1, max>', ob_get_level());
assertType('string', ob_get_clean());
assertType('(string|false)', ob_get_clean());
}

class Service
Expand Down Expand Up @@ -245,7 +245,7 @@ function pureMethodKeepsLevel(Service $service): void
ob_start();
$x=$service->pureMethod();
assertType('int<1, max>', ob_get_level());
assertType('string', ob_get_clean());
assertType('(string|false)', ob_get_clean());
}

function impureStaticMethodForgetsLevel(): void
Expand All @@ -269,23 +269,23 @@ function arrayMapPureCallbackKeepsLevel(array $a): void
ob_start();
array_map('strtoupper', $a);
assertType('int<1, max>', ob_get_level());
assertType('string', ob_get_clean());
assertType('(string|false)', ob_get_clean());
}

function laterInvokedCallableKeepsLevel(callable $cb): void
{
ob_start();
register_shutdown_function($cb);
assertType('int<1, max>', ob_get_level());
assertType('string', ob_get_clean());
assertType('(string|false)', ob_get_clean());
}

function builtinKeepsLevel(): void
{
ob_start();
printf('hello');
assertType('int<1, max>', ob_get_level());
assertType('string', ob_get_clean());
assertType('(string|false)', ob_get_clean());
}

class WithImpureConstructor
Expand Down Expand Up @@ -326,15 +326,15 @@ function pureConstructorKeepsLevel(): void
ob_start();
new WithPureConstructor();
assertType('int<1, max>', ob_get_level());
assertType('string', ob_get_clean());
assertType('(string|false)', ob_get_clean());
}

function noConstructorKeepsLevel(): void
{
ob_start();
new WithoutConstructor();
assertType('int<1, max>', ob_get_level());
assertType('string', ob_get_clean());
assertType('(string|false)', ob_get_clean());
}

/** @param class-string $className */
Expand All @@ -351,7 +351,7 @@ function builtinConstructorKeepsLevel(): void
ob_start();
new \ArrayObject();
assertType('int<1, max>', ob_get_level());
assertType('string', ob_get_clean());
assertType('(string|false)', ob_get_clean());
}

function withRequire(): void
Expand Down
5 changes: 5 additions & 0 deletions tests/PHPStan/Rules/Comparison/StrictComparisonOfDifferentTypesRuleTest.php
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Original file line number Diff line number Diff line change
Expand Up @@ -1261,6 +1261,11 @@ public function testBug14878(): void
$this->analyse([__DIR__ . '/../../Analyser/nsrt/bug-14878.php'], []);
}

public function testBug14985(): void
{
$this->analyse([__DIR__ . '/data/bug-14985.php'], []);
}

public function testBug14847(): void
{
$this->analyse([__DIR__ . '/data/bug-14847.php'], [
Expand Down
15 changes: 15 additions & 0 deletions tests/PHPStan/Rules/Comparison/data/bug-14985.php
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Original file line number Diff line number Diff line change
@@ -0,0 +1,15 @@
<?php

declare(strict_types=1);

namespace Bug14985;

ob_start();
$a = ob_get_clean();

// There is no check whether ob_start() was successful, so the if condition cannot be guaranteed to be always false, as PHPStan claims.
if ($a === false) {
echo "false";
}


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