LogarithmInvalidRealDomain

warning native on by default

Group: Probable bugs

Use a positive logarithm argument.

Example

<?php
$n = log(-7);

Reported:

• line 2: Use a positive logarithm argument.

Detection

• log, log10 or log1p has a proven numeric value outside its real-valued finite-result domain: log/log10 argument <= 0; log1p argument <= -1. Also report log base <= 0 or equal to 1 when explicit.
• Resolve builtin functions, extension classes, constants and method receivers, including aliases and supported named arguments. Inspect reachable operations in one lexical scope with bounded local flow.
• Emit one finding per violating operation. Never infer policy from names or comments. When the proof is inconclusive, nothing is reported.

Exceptions (no report)

• Exclude shadowed or unresolved symbols, incomplete code, unknown required constants, ambiguous receiver identity and unsupported versions. Reassignment, escaping aliases, and unknown calls invalidate dependent flow facts.
• Both @custos-ignore LogarithmInvalidRealDomain and @noinspection LogarithmInvalidRealDomain suppress this native rule.

Fix

None. A safe repair requires choosing values, error handling, or application behavior.

PHP versions

Apply throughout PHP 5.3–8.5 only where the extension API and syntax exist. Do not flag API unavailability through this rule.

Options

None. Use normal rule configuration to enable or disable the inspection.

Configure

In custos.json:

{
  "rules": {
    "LogarithmInvalidRealDomain": {
      "enabled": false
    }
  }
}

Suppress

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

// @custos-ignore LogarithmInvalidRealDomain