StringOffsetWriteTruncatesValue

error native on by default

Group: Probable bugs

Identify assignment of a proven string longer than one byte to an integer offset on a value proven to be a string; multibyte character strings still count bytes.

Detection

• Report assignment of a proven string longer than one byte to an integer offset on a value proven to be a string; multibyte character strings still count bytes.
• Resolve builtin functions, classes, constants and methods, including imports and supported named arguments. Follow only bounded local facts within one lexical scope. Receiver and argument provenance must establish the specific API contract; variable names and comments never prove intent.
• Report one finding per violating operation. A reachable path, unchanged value identity and applicable API behavior are required. Intervening mutation, unknown calls involving tracked values, escaped aliases or exhausted analysis budgets invalidate proof.

Exceptions (no report)

• Exclude unresolved required symbols, user-defined lookalikes, incomplete syntax, unknown required values and unsupported versions.
• Both @custos-ignore StringOffsetWriteTruncatesValue and @noinspection StringOffsetWriteTruncatesValue suppress this native rule.

Fix

None. A repair requires a semantic decision or application error-handling policy.

PHP versions

Available in PHP 5.3–8.5 where the referenced API exists. Do not apply extension contracts when the resolved API is unavailable. Gate syntax and version-specific behavior to the configured target.

Configure

In custos.json:

{
  "rules": {
    "StringOffsetWriteTruncatesValue": {
      "enabled": false
    }
  }
}

Suppress

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

// @custos-ignore StringOffsetWriteTruncatesValue