CtypeIntegerInterpretedAsCharacterCode

warning native off by default

Group: Probable bugs

An integer ctype argument can be interpreted as a character code. Pass a string when testing the characters of its decimal representation. This inspection is disabled by default because the intended policy or use can vary.

Example

<?php
$ok=ctype_digit(48);

Reported:

• line 2: Pass a string to avoid character-code interpretation.

Detection

• Resolved ctype_digit receives integer literal in range 0–255; report disabled-by-default interpretation/deprecation hazard. String literals and explicit string casts excluded; initial detector restricts to ctype_digit rather than all ctype functions.
• Resolve builtin functions, classes, constants and methods; user-defined lookalikes are excluded. Follow only bounded local proof in one lexical scope.
• Emit one finding per violating operation, not per supporting evidence statement. When the proof is inconclusive, nothing is reported.

Exceptions (no report)

• Do not report unresolved or shadowed builtin names, unknown values, or incomplete receiver/type provenance. Unknown calls, aliases escaping, and intervening writes invalidate local proof. Similar code outside the stated detection contract is not a finding.
• Both standard suppression forms suppress this native ID.

Fix

None. Choosing a repair requires intent or additional runtime information.

PHP versions

Available throughout supported PHP 5.3–8.5 where the referenced builtin/extension is available. Respect syntax/version-specific receiver contracts; unavailable APIs are not this rule’s concern.

Configure

In custos.json:

{
  "rules": {
    "CtypeIntegerInterpretedAsCharacterCode": {
      "enabled": true
    }
  }
}

Suppress

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

// @custos-ignore CtypeIntegerInterpretedAsCharacterCode