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Report maybe division by zero in InvalidBinaryOperationRule #3419

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1 change: 1 addition & 0 deletions conf/config.level2.neon
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Original file line number Diff line number Diff line change
Expand Up @@ -184,6 +184,7 @@ services:
class: PHPStan\Rules\Operators\InvalidBinaryOperationRule
arguments:
bleedingEdge: %featureToggles.bleedingEdge%
reportMaybes: %reportMaybes%
tags:
- phpstan.rules.rule
-
Expand Down
9 changes: 8 additions & 1 deletion src/Parser/TryCatchTypeVisitor.php
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Expand Up @@ -24,7 +24,14 @@ public function beforeTraverse(array $nodes): ?array

public function enterNode(Node $node): ?Node
{
if ($node instanceof Node\Stmt || $node instanceof Node\Expr\Match_) {
if (
$node instanceof Node\Stmt
|| $node instanceof Node\Expr\Match_
|| $node instanceof Node\Expr\AssignOp\Div
|| $node instanceof Node\Expr\AssignOp\Mod
|| $node instanceof Node\Expr\BinaryOp\Div
|| $node instanceof Node\Expr\BinaryOp\Mod
) {
if (count($this->typeStack) > 0) {
$node->setAttribute(self::ATTRIBUTE_NAME, $this->typeStack[count($this->typeStack) - 1]);
}
Expand Down
68 changes: 68 additions & 0 deletions src/Rules/Operators/InvalidBinaryOperationRule.php
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Expand Up @@ -2,17 +2,24 @@

namespace PHPStan\Rules\Operators;

use DivisionByZeroError;
use PhpParser\Node;
use PHPStan\Analyser\MutatingScope;
use PHPStan\Analyser\Scope;
use PHPStan\Node\Printer\ExprPrinter;
use PHPStan\Parser\TryCatchTypeVisitor;
use PHPStan\Rules\Rule;
use PHPStan\Rules\RuleErrorBuilder;
use PHPStan\Rules\RuleLevelHelper;
use PHPStan\ShouldNotHappenException;
use PHPStan\Type\BenevolentUnionType;
use PHPStan\Type\Constant\ConstantIntegerType;
use PHPStan\Type\ErrorType;
use PHPStan\Type\ObjectType;
use PHPStan\Type\Type;
use PHPStan\Type\TypeCombinator;
use PHPStan\Type\VerbosityLevel;
use function array_map;
use function sprintf;
use function strlen;
use function substr;
Expand All @@ -27,6 +34,7 @@ public function __construct(
private ExprPrinter $exprPrinter,
private RuleLevelHelper $ruleLevelHelper,
private bool $bleedingEdge,
private bool $reportMaybes,
)
{
}
Expand Down Expand Up @@ -108,6 +116,39 @@ public function processNode(Node $node, Scope $scope): array
->assignVariable($rightName, $rightType, $rightType);

if (!$scope->getType($newNode) instanceof ErrorType) {
if (
$this->reportMaybes
&& (
$node instanceof Node\Expr\AssignOp\Div
|| $node instanceof Node\Expr\AssignOp\Mod
|| $node instanceof Node\Expr\BinaryOp\Div
|| $node instanceof Node\Expr\BinaryOp\Mod
)
&& !$this->isDivisionByZeroCaught($node)
&& !$this->hasDivisionByZeroThrowsTag($scope)
) {
$rightType = $scope->getType($right);
// as long as we don't support float-ranges, we prevent false positives for maybe floats
if ($rightType instanceof BenevolentUnionType && $rightType->isFloat()->maybe()) {
return [];
}

$zeroType = new ConstantIntegerType(0);
if ($zeroType->isSuperTypeOf($rightType)->maybe()) {
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This logic should be implemented as a $callback for the RuleLevelHelper above instead. It will make sure this is correctly reported on level 2 (when it's always zero) and on level 7 (when it might be a zero).

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the callback passed to RuleLevelHelper is only invoked for union types and intersection types.
in our case we pass in a expr which is resolved into a IntegerRangeType, which means the callback does not have any effect in this context.

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I get it. But still I'm missing at least asking for $this->reportMaybes so that maybe-zero is reported only on level 7+.

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Hey, it'd still be useful if the RuleLeveLHelper eliminated some situations. I can see that in the tests you're currently asserting an error that shouldn't be asserted because it's on a BenevolentUnionType.

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I tried testing the benevolent case, but for some reason the benevolence is lost somewhere?

https://phpstan.org/r/c0d12375-468d-46a2-8778-fcedc0d5e26f

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That's not how you type a benevolent union type in PHPDoc.

It's not officially supported, there's just a semi-secret pseudotype __benevolent<...>. Check the functionMap.

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@staabm staabm Sep 11, 2024 •
edited
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ok, hopefully I got it right now. my understanding about the expected results about the divisor are

  • we should not error on benevolent unions containing float (no matter the $checkBenevolentUnionTypes flag)
  • we should not error on float
  • we should error on unions with int|float
  • we should error on benevolent unions with non-float but number-castable types respecting $checkBenevolentUnionTypes (e.g. (int|true))

I tried endless variants of how to represent this condition via RuleLevelHelper callback, but couldn't find one which works for all this conditions

return [
RuleErrorBuilder::message(sprintf(
'Binary operation "%s" between %s and %s might result in an error.',
substr(substr($this->exprPrinter->printExpr($newNode), strlen($leftName) + 2), 0, -(strlen($rightName) + 2)),
$scope->getType($left)->describe(VerbosityLevel::value()),
$scope->getType($right)->describe(VerbosityLevel::value()),
))
->line($left->getStartLine())
->identifier(sprintf('%s.invalid', $identifier))
->build(),
];
}
}

return [];
}

Expand All @@ -124,4 +165,31 @@ public function processNode(Node $node, Scope $scope): array
];
}

private function isDivisionByZeroCaught(Node $node): bool
{
$tryCatchTypes = $node->getAttribute(TryCatchTypeVisitor::ATTRIBUTE_NAME);
if ($tryCatchTypes === null) {
return false;
}

$tryCatchType = TypeCombinator::union(...array_map(static fn (string $class) => new ObjectType($class), $tryCatchTypes));

return $tryCatchType->isSuperTypeOf(new ObjectType(DivisionByZeroError::class))->yes();
}

private function hasDivisionByZeroThrowsTag(Scope $scope): bool
{
$function = $scope->getFunction();
if ($function === null) {
return false;
}

$throwsType = $function->getThrowType();
if ($throwsType === null) {
return false;
}

return $throwsType->isSuperTypeOf(new ObjectType(DivisionByZeroError::class))->yes();
}

}
144 changes: 141 additions & 3 deletions tests/PHPStan/Rules/Operators/InvalidBinaryOperationRuleTest.php
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Expand Up @@ -19,11 +19,14 @@ class InvalidBinaryOperationRuleTest extends RuleTestCase

private bool $checkImplicitMixed = false;

private bool $checkBenevolentUnionTypes = false;

protected function getRule(): Rule
{
return new InvalidBinaryOperationRule(
new ExprPrinter(new Printer()),
new RuleLevelHelper($this->createReflectionProvider(), true, false, true, $this->checkExplicitMixed, $this->checkImplicitMixed, true, false),
new RuleLevelHelper($this->createReflectionProvider(), true, false, true, $this->checkExplicitMixed, $this->checkImplicitMixed, true, $this->checkBenevolentUnionTypes),
true,
true,
);
}
Expand Down Expand Up @@ -282,7 +285,12 @@ public function testBug3515(): void

public function testBug8827(): void
{
$this->analyse([__DIR__ . '/../../Analyser/nsrt/bug-8827.php'], []);
$this->analyse([__DIR__ . '/../../Analyser/nsrt/bug-8827.php'], [
[
'Binary operation "/" between int<0, max> and int<0, max> might result in an error.',
25,
],
]);
}

public function testRuleWithNullsafeVariant(): void
Expand Down Expand Up @@ -659,6 +667,14 @@ public function testBenevolentUnion(): void
'Binary operation "/" between (array<string, string>|bool|int|object|resource) and BinaryOpBenevolentUnion\\Foo results in an error.',
105,
],
[
'Binary operation "/" between (array<string, string>|bool|int|object|resource) and (array<string, string>|bool|int|object|resource) might result in an error.',
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This one. It might be int / int so this shouldn't be reported.

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Oh I get it, but int can still include zero so this should be reported.

But: We can still create an artifical example for example of (float|int) that shouldn't be reported because we don't report X / float.

108,
],
[
'Binary operation "/=" between 1 and (array<string, string>|bool|int|object|resource) might result in an error.',
111,
],
[
'Binary operation "/=" between array{} and (array<string, string>|bool|int|object|resource) results in an error.',
114,
Expand All @@ -667,14 +683,34 @@ public function testBenevolentUnion(): void
'Binary operation "/=" between BinaryOpBenevolentUnion\\Foo and (array<string, string>|bool|int|object|resource) results in an error.',
117,
],
[
"Binary operation \"/=\" between '123' and (array<string, string>|bool|int|object|resource) might result in an error.",
120,
],
[
'Binary operation "/=" between 1.23 and (array<string, string>|bool|int|object|resource) might result in an error.',
123,
],
[
'Binary operation "/=" between (array<string, string>|bool|int|object|resource) and (array<string, string>|bool|int|object|resource) might result in an error.',
126,
],
[
'Binary operation "%" between (array<string, string>|bool|int|object|resource) and array{} results in an error.',
135,
],
[
'Binary operation "%" between (array<string, string>|bool|int|object|resource) and BinaryOpBenevolentUnion\\Foo results in an error.',
'Binary operation "%" between (array<string, string>|bool|int|object|resource) and BinaryOpBenevolentUnion\Foo results in an error.',
136,
],
[
'Binary operation "%" between (array<string, string>|bool|int|object|resource) and (array<string, string>|bool|int|object|resource) might result in an error.',
139,
],
[
'Binary operation "%=" between 1 and (array<string, string>|bool|int|object|resource) might result in an error.',
142,
],
[
'Binary operation "%=" between array{} and (array<string, string>|bool|int|object|resource) results in an error.',
145,
Expand All @@ -683,6 +719,18 @@ public function testBenevolentUnion(): void
'Binary operation "%=" between BinaryOpBenevolentUnion\\Foo and (array<string, string>|bool|int|object|resource) results in an error.',
148,
],
[
"Binary operation \"%=\" between '123' and (array<string, string>|bool|int|object|resource) might result in an error.",
151,
],
[
'Binary operation "%=" between 1.23 and (array<string, string>|bool|int|object|resource) might result in an error.',
154,
],
[
'Binary operation "%=" between (array<string, string>|bool|int|object|resource) and (array<string, string>|bool|int|object|resource) might result in an error.',
157,
],
[
'Binary operation "-" between (array<string, string>|bool|int|object|resource) and array{} results in an error.',
166,
Expand Down Expand Up @@ -810,4 +858,94 @@ public function testBug7863(): void
]);
}

/**
* @dataProvider dataDivisionByMaybeZero
* @param list<array{0: string, 1: int, 2?: string|null}> $expectedErrors
*/
public function testDivisionByMaybeZero(bool $checkBenevolentUnionTypes, array $expectedErrors): void
{
$this->checkBenevolentUnionTypes = $checkBenevolentUnionTypes;

$this->analyse([__DIR__ . '/data/invalid-division.php'], $expectedErrors);
}

public function dataDivisionByMaybeZero(): iterable
{
yield [
false,
[
[
'Binary operation "/" between int and int<0, max> might result in an error.',
12,
],
[
'Binary operation "/=" between int and int<0, max> might result in an error.',
13,
],
[
'Binary operation "%" between int and int<0, max> might result in an error.',
21,
],
[
'Binary operation "%=" between int and int<0, max> might result in an error.',
22,
],
[
'Binary operation "/" between int and int<0, max> might result in an error.',
61,
],
[
'Binary operation "/" between int and float|int might result in an error.',
90,
],
[
'Binary operation "/" between int and (int|true) might result in an error.',
106,
],
[
'Binary operation "/" between int and -5|int<0, max> might result in an error.',
123,
],
],
];

yield [
true,
[
[
'Binary operation "/" between int and int<0, max> might result in an error.',
12,
],
[
'Binary operation "/=" between int and int<0, max> might result in an error.',
13,
],
[
'Binary operation "%" between int and int<0, max> might result in an error.',
21,
],
[
'Binary operation "%=" between int and int<0, max> might result in an error.',
22,
],
[
'Binary operation "/" between int and int<0, max> might result in an error.',
61,
],
[
'Binary operation "/" between int and float|int might result in an error.',
90,
],
[
'Binary operation "/" between int and (int|true) might result in an error.',
106,
],
[
'Binary operation "/" between int and -5|int<0, max> might result in an error.',
123,
],
],
];
}

}
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