GdAlphaOutsideSupportedRange

error native on by default

Group: Probable bugs

Identify imagecolorallocatealpha or imagecolorclosestalpha with known integer alpha below zero or above127.

Detection

• Report imagecolorallocatealpha or imagecolorclosestalpha with known integer alpha below zero or above127.
• 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.
• An integer interval proves invalid alpha only when entirely below zero or entirely above 127. A concrete, loop-free path from the start of the scope may establish an invalid first read before a later loop rewrites the value. Unknown branches, prior calls, references and unsupported operations end that additional proof. Steps and fresh assignments are evaluated in order; merely creating an uninvoked capture does not execute it. Crossing intervals and arithmetic that may overflow to float provide no range proof. Loop heads widen after their second visit, and integer comparisons narrow their body values.
• Both @custos-ignore GdAlphaOutsideSupportedRange and @noinspection GdAlphaOutsideSupportedRange 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": {
    "GdAlphaOutsideSupportedRange": {
      "enabled": false
    }
  }
}

Suppress

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

// @custos-ignore GdAlphaOutsideSupportedRange