ExceptionConstructedNotThrown

warning native on by default

Group: Probable bugs

Constructing an exception and discarding it does not interrupt execution. Throw the exception when the failure should stop the operation.

Example

<?php
new RuntimeException("Invalid");

Reported:

• line 2: Throw the discarded exception.

Detection

• A standalone new-expression statement constructs a resolved Throwable subtype, with no assignment, return, throw or use of the result. User class ancestry must prove Throwable; recognize resolved builtin exception classes.
• 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.
• Exclude a Throwable class with a custom constructor or destructor: constructing or disposing of that object can be intentional observable work. Require the supported builtin lifecycle contract, including inherited builtin methods for resolved subtypes.
• 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": {
    "ExceptionConstructedNotThrown": {
      "enabled": false
    }
  }
}

Suppress

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

// @custos-ignore ExceptionConstructedNotThrown