DivisionFromZero::pass() - Code Metrics - Inspection of "Add Division analzers" - ovr/phpsa - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Pull Request — master (#254)

by Enrico

created 2016-10-13 18:06 UTC

DivisionFromZero::pass() B

↳ Parent: DivisionFromZero

Complexity

Conditions	4
Paths	6

Size

Total Lines	22
Code Lines	13

Duplication

Lines	0
Ratio	0 %

Importance

Changes	1
Bugs	0	Features	0

Metric	Value
cc	4
eloc	13
nc	6
nop	2
dl	0
loc	22
rs	8.9197
c	1
b	0
f	0

<?php

namespace PHPSA\Analyzer\Pass\Expression;

use PhpParser\Node\Expr;
use PHPSA\Analyzer\Helper\DefaultMetadataPassTrait;
use PHPSA\Analyzer\Pass\AnalyzerPassInterface;
use PHPSA\Context;

class DivisionFromZero implements AnalyzerPassInterface
{
    use DefaultMetadataPassTrait;

    const DESCRIPTION = 'Checks for division from 0. For example: `0/$x`, `false%$x`';

    /**
     * @param Expr $expr
     * @param Context $context
     * @return bool
     */
    public function pass(Expr $expr, Context $context)
    {
        $compiler = $context->getExpressionCompiler();

        if ($expr instanceof Expr\AssignOp) {
            $left = $compiler->compile($expr->var);
        } elseif ($expr instanceof Expr\BinaryOp) {
            $left = $compiler->compile($expr->left);
        }

        if ($left->getValue() == 0) {
function myFunction($a) {
    switch ($a) {
        case 'foo':
            $x = 1;
            break;

        case 'bar':
            $x = 2;
            break;
    }

    // $x is potentially undefined here.
    echo $x;
}
            $context->notice(
                'division_from_zero',
                "You are trying to divide from zero",
                $expr
            );

            return true;
        }
        
        return false;
    }

    /**
     * @return array
     */
    public function getRegister()
    {
        return [
            Expr\BinaryOp\Div::class,
            Expr\BinaryOp\Mod::class,
            Expr\AssignOp\Div::class,
            Expr\AssignOp\Mod::class,
        ];
    }
}


1			<?php
2
3			namespace PHPSA\Analyzer\Pass\Expression;
4
5			use PhpParser\Node\Expr;
6			use PHPSA\Analyzer\Helper\DefaultMetadataPassTrait;
7			use PHPSA\Analyzer\Pass\AnalyzerPassInterface;
8			use PHPSA\Context;
9
10			class DivisionFromZero implements AnalyzerPassInterface
11			{
12			use DefaultMetadataPassTrait;
13
14			const DESCRIPTION = 'Checks for division from 0. For example: `0/$x`, `false%$x`';
15
16			/**
17			* @param Expr $expr
18			* @param Context $context
19			* @return bool
20			*/
21			public function pass(Expr $expr, Context $context)
22			{
23			$compiler = $context->getExpressionCompiler();
24
25			if ($expr instanceof Expr\AssignOp) {
26			$left = $compiler->compile($expr->var);
27			} elseif ($expr instanceof Expr\BinaryOp) {
28			$left = $compiler->compile($expr->left);
29			}
30
31			if ($left->getValue() == 0) {
			0 ignored issues – show Bug introduced 2016-10-13 18:19 UTC by Report Bug Copy Issue Report The variable `$left` does not seem to be defined for all execution paths leading up to this point. If you define a variable conditionally, it can happen that it is not defined for all execution paths. Let’s take a look at an example: function myFunction($a) { switch ($a) { case 'foo': $x = 1; break; case 'bar': $x = 2; break; } // $x is potentially undefined here. echo $x; } In the above example, the variable `$x` is defined if you pass “foo” or “bar” as argument for `$a`. However, since the `switch` statement has no default case statement, if you pass any other value, the variable `$x` would be undefined. Available Fixes Check for existence of the variable explicitly: function myFunction($a) { switch ($a) { case 'foo': $x = 1; break; case 'bar': $x = 2; break; } if (isset($x)) { // Make sure it's always set. echo $x; } } Define a default value for the variable: function myFunction($a) { $x = ''; // Set a default which gets overridden for certain paths. switch ($a) { case 'foo': $x = 1; break; case 'bar': $x = 2; break; } echo $x; } Add a value for the missing path: function myFunction($a) { switch ($a) { case 'foo': $x = 1; break; case 'bar': $x = 2; break; // We add support for the missing case. default: $x = ''; break; } echo $x; } Loading history...
32			$context->notice(
33			'division_from_zero',
34			"You are trying to divide from zero",
35			$expr
36			);
37
38			return true;
39			}
40
41			return false;
42			}
43
44			/**
45			* @return array
46			*/
47			public function getRegister()
48			{
49			return [
50			Expr\BinaryOp\Div::class,
51			Expr\BinaryOp\Mod::class,
52			Expr\AssignOp\Div::class,
53			Expr\AssignOp\Mod::class,
54			];
55			}
56			}
57

ovr / phpsa

Pull Request — master (#254)

DivisionFromZero::pass() B

Complexity

Size

Duplication

Importance

Available Fixes

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