FileWriteResultUnchecked

warning native on by default

Group: Probable bugs

Detect discarded file_put_contents followed on the same path by a resolved success marker: an unconditional return true or literal success response.

Example

<?php
function bad($path, $payload) { file_put_contents($path, $payload); return true; }

Reported:

• line 2: Verify the write before reporting success.

Detection

• Report discarded file_put_contents followed on the same path by a resolved success marker: an unconditional return true or literal success response.
• 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, recursion or analysis-budget exhaustion cannot establish definite facts.

Exceptions (no report)

• Writes whose result is checked or whose function explicitly does not promise persistence are excluded; do not identify success from function names.
• 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.

Fix

No automatic fix: handling partial or failed writes requires an application contract.

PHP versions

Apply only on PHP versions supporting the referenced APIs and syntax (within PHP 5.3–8.5). 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": {
    "FileWriteResultUnchecked": {
      "enabled": false
    }
  }
}

Suppress

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

// @custos-ignore FileWriteResultUnchecked