ExhaustedGeneratorReused

error native on by default PHP ≥ 5.5

Group: Probable bugs

Detect a resolved Generator identity traversed again after a proven complete iterator_to_array call or complete foreach.

Example

<?php
function values() { yield 1; } $g = values(); iterator_to_array($g); foreach ($g as $v) {}

Reported:

• line 2: Create a fresh generator before traversing again.

Detection

• Report a resolved Generator identity traversed again after a proven complete iterator_to_array call or complete foreach.
• Resolve builtin calls and named arguments before checking the contract. Project-local callees are considered only when their bodies or immutable summaries establish the required facts. The default is enabled, with positive proof required.
• For flow-dependent conditions, require a reachable source-to-use path with no intervening invalidation. Unknown calls, ambiguous aliases or recursion cannot establish definite facts. When the proof is inconclusive, nothing is reported.
• The traversed expression must be a plain local variable in both traversals. A call, property or other expression may hand back a different generator each time it is evaluated, so two textually identical calls are never one identity.

Exceptions (no report)

• Early breaks, potentially exceptional completion, IteratorAggregate values, and creation of a fresh generator invalidate exhaustion proof.
• Unresolved targets, incomplete required facts, suppressed findings and PHP versions lacking the referenced API or language feature produce no report. User declarations shadowing builtin names are not builtin contracts.
• No report after a proven iterator_to_array when the variable can be rebound by code the local flow facts do not follow: a closure capturing it by reference, a global or static declaration of it in the same scope (for top-level code, a global declaration of it in any function of the file), an extract or parse_str call or an include/require in the same scope.
• The directly preceding empty foreach proves exhaustion only when it iterates by value and does not reuse the generator variable as its own key or value target.

Fix

No automatic fix: recreation and materialization have different side effects and memory costs.

PHP versions

Available from PHP 5.5. Builtin behavior and argument contracts follow the configured PHP version. Extension-specific calls require resolved extension API symbols; do not treat same-named application functions as extension calls.

Options

None. Enable or disable this rule through normal rule configuration.

Configure

In custos.json:

{
  "rules": {
    "ExhaustedGeneratorReused": {
      "enabled": false
    }
  }
}

Suppress

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

// @custos-ignore ExhaustedGeneratorReused