IntlGregorianMonthOffByOne

warning native off by default PHP ≥ 5.5

Group: Probable bugs

Use zero-based Gregorian month numbers. This opt-in rule applies the policy described in Detection.

Example

<?php
$c = new IntlGregorianCalendar(); $c->set(2026, 12, 18);

Reported:

• line 2: Use zero-based Gregorian month numbers.

Detection

• Enabled policy states that literal month arguments use conventional month numbering. Report a literal integer 1 through 12 in the month position of a resolved IntlGregorianCalendar constructor or its set(year, month, day) form. Skip computed month values, field/value set forms, and unresolved constructors.
• Resolve builtin functions, extension classes, method receivers, constants and named arguments. Follow unchanged locals and aliases only within the same bounded lexical scope. Require a reachable path; merge branch facts only when all incoming paths establish them.
• Emit one finding at the violating operation, not one per evidence statement. Rebinding, writes, by-reference escape, unresolved calls that can mutate relevant state, and exhausted analysis budgets remove proof.

Exceptions (no report)

• Exclude shadowed builtins, unresolved receivers, incomplete syntax and unknown prerequisite facts. An extension function name alone does not prove an application function is that builtin.
• A dominating valid guard or repair described in Detection prevents the finding. Both legacy noinspection and custos-ignore forms suppress this ID.

Fix

No automatic fix. The required repair depends on error handling, data selection, lifecycle ordering or application policy.

All edits use exact byte ranges and preserve comments and evaluation order. Offer no fix when its stated prerequisites cannot be proven or the replacement is unsupported by the configured PHP version.

PHP versions

Requires PHP 5.5 or later and the referenced extension API. Respect method-specific introduction versions within PHP 5.3–8.5; unsupported optional APIs cannot establish facts. Named arguments require PHP 8.0 or later.

Configure

In custos.json:

{
  "rules": {
    "IntlGregorianMonthOffByOne": {
      "enabled": true
    }
  }
}

Suppress

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

// @custos-ignore IntlGregorianMonthOffByOne