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Commit a9f590b

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Prevent accurate comparison of floating-point numbers
1 parent 18c0b6e commit a9f590b

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3 files changed

+107
-0
lines changed

3 files changed

+107
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lines changed
Lines changed: 61 additions & 0 deletions
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<?php declare(strict_types = 1);
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namespace PHPStan\Rules\Operators;
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use PhpParser\Node;
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use PhpParser\Node\Expr\BinaryOp;
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use PHPStan\Analyser\Scope;
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use PHPStan\Rules\Rule;
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use PHPStan\Type\FloatType;
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class OperandsInComparisonRule implements Rule
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{
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public function getNodeType(): string
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{
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return BinaryOp::class;
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}
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/**
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* @param Node $node
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* @param Scope $scope
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* @return string[]
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*/
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public function processNode(Node $node, Scope $scope): array
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{
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if (!$node instanceof BinaryOp\Equal
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&& !$node instanceof BinaryOp\Identical
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&& !$node instanceof BinaryOp\GreaterOrEqual
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&& !$node instanceof BinaryOp\SmallerOrEqual
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) {
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return [];
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}
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$rightType = $scope->getType($node->right);
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$leftType = $scope->getType($node->left);
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if ($rightType instanceof FloatType || $leftType instanceof FloatType) {
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if ($node instanceof BinaryOp\Equal || $node instanceof BinaryOp\Identical) {
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return [
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'You can not use an exact comparison for floating-point numbers.
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Should use `abs($left - $right) < $epsilon`, where $epsilon maximum permissible error.',
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];
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}
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if ($node instanceof BinaryOp\GreaterOrEqual) {
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return [
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'You can not use an exact comparison for floating-point numbers.
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Should use `$left - $right >= $epsilon`, where $epsilon maximum permissible error.',
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];
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}
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if ($node instanceof BinaryOp\SmallerOrEqual) {
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return [
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'You can not use an exact comparison for floating-point numbers.
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Should use `$right - $left >= $epsilon`, where $epsilon maximum permissible error.',
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];
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}
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}
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return [];
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}
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}
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<?php declare(strict_types = 1);
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namespace PHPStan\Rules\Operators;
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use PHPStan\Rules\Rule;
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class OperandsInComparisonRuleTest extends \PHPStan\Testing\RuleTestCase
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{
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protected function getRule(): Rule
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{
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return new OperandsInComparisonRule();
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}
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public function testRule(): void
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{
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$this->analyse([__DIR__ . '/data/operators.php'], [
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[
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'You can not use an exact comparison for floating-point numbers.
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Should use `abs($left - $right) < $epsilon`, where $epsilon maximum permissible error.',
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113,
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],
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[
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'You can not use an exact comparison for floating-point numbers.
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Should use `abs($left - $right) < $epsilon`, where $epsilon maximum permissible error.',
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114,
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],
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[
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'You can not use an exact comparison for floating-point numbers.
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Should use `$left - $right >= $epsilon`, where $epsilon maximum permissible error.',
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115,
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],
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[
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'You can not use an exact comparison for floating-point numbers.
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Should use `$right - $left >= $epsilon`, where $epsilon maximum permissible error.',
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116,
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],
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]);
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}
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}

‎tests/Rules/Operators/data/operators.php‎

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explode($mixed, $mixed) + $int;
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};
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$float === 123.2;
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$float == 123.2;
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$float >= 123.2;
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$float <= 123.2;

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