StrlenInEmptyStringCheckContext

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Group: Control flow · PhpStorm name: StrlenInEmptyStringCheckContextInspection

Measuring a string's length only to know whether it is empty (strlen($s) > 0, !mb_strlen($s), if (strlen($s))) is indirect and slower than comparing with the empty string. Suggest an identity comparison with '' instead, casting to string when the value is not known to be a string.

Example

Yoda style:

Before

<?php
function probe(string $name, ?string $alias, int $count, $raw, array $bag)
{
    if (strlen($name)) {}
    while (!mb_strlen($name, 'UTF-8')) {}
    if (!(strlen($alias))) {}
    $a = mb_strlen($raw) ? 'y' : 'n';
    $b = $count > 2 and strlen(trim($raw));

    $c = 0 === mb_strlen($name);
    $d = strlen($count) <> 0;
    $e = strlen($alias)  ==  0;
    $f = mb_strlen($name) > 0;
    $g = strlen($bag['k']) >= 1;
    $h = strlen($name) < 1;

    $i = 0 < strlen($name);
    $j = strlen($name) > 1;
    $k = (strlen($name)) > 0;
    $l = strlen($name) ?: 5;
    return strlen($name);
}

if (strlen($argv[1])) {}

After fix

<?php
function probe(string $name, ?string $alias, int $count, $raw, array $bag)
{
    if ('' !== $name) {}
    while ('' === $name) {}
    if (!('' !== (string)$alias)) {}
    $a = '' !== (string)$raw ? 'y' : 'n';
    $b = $count > 2 and '' !== trim($raw);

    $c = '' === $name;
    $d = '' !== (string)$count;
    $e = '' === (string)$alias;
    $f = '' !== $name;
    $g = '' !== (string)$bag['k'];
    $h = '' === $name;

    $i = 0 < strlen($name);
    $j = strlen($name) > 1;
    $k = (strlen($name)) > 0;
    $l = strlen($name) ?: 5;
    return strlen($name);
}

if ('' !== (string)$argv[1]) {}

Reported:

• line 4: Compare with an empty string instead: ''' !== $name'.
• line 5: Compare with an empty string instead: ''' === $name'.
• line 6: Compare with an empty string instead: ''' !== (string)$alias'.
• line 7: Compare with an empty string instead: ''' !== (string)$raw'.
• line 8: Compare with an empty string instead: ''' !== trim($raw)'.
• line 10: Compare with an empty string instead: ''' === $name'.
• line 11: Compare with an empty string instead: ''' !== (string)$count'.
• line 12: Compare with an empty string instead: ''' === (string)$alias'.
• line 13: Compare with an empty string instead: ''' !== $name'.
• line 14: Compare with an empty string instead: ''' !== (string)$bag['k']'.
• line 15: Compare with an empty string instead: ''' === $name'.
• line 24: Compare with an empty string instead: ''' !== (string)$argv[1]'.

Options

Option	Type	Default	Effect
(none)			Operand order follows the global comparison style (regular default / yoda).

Configure

In custos.json:

{
  "rules": {
    "StrlenInEmptyStringCheckContext": {
      "enabled": false
    }
  }
}

Suppress

Before the statement or declaration (or the first statement of the file), either of:

// @custos-ignore StrlenInEmptyStringCheckContext

/**
 * @noinspection StrlenInEmptyStringCheckContextInspection
 */