ConflictingContentLengthHeaders

warning native on by default

Group: Probable bugs

Send one consistent Content-Length value.

Example

Finding:

<?php
header("Content-Length: 4"); header("Content-Length: 8", false);

Reported:

• line 2: Send one consistent Content-Length value.

Detection

• Track header calls with constant Content-Length values and replacement flag. Report a call appending a different valid decimal value while an earlier effective Content-Length remains. Header names are case insensitive; trim optional whitespace. Numerically equal decimal lengths are consistent.
• Emit one finding per violating operation. Flow facts require a reachable path with no intervening mutation, escaped alias or unknown call involving the tracked value. When the proof is inconclusive, nothing is reported.

Exceptions (no report)

• Replacement calls, header_remove, equal values, unknown header values and branch-dependent state are excluded.
• Exclude shadowed builtin symbols, unresolved required types, incomplete syntax and unsupported PHP versions.

Fix

No automatic fix. Choosing a repair requires runtime information, error-handling policy or a semantic decision.

PHP versions

Available throughout PHP 5.3–8.5.

Configure

In custos.json:

{
  "rules": {
    "ConflictingContentLengthHeaders": {
      "enabled": false
    }
  }
}

Suppress

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

// @custos-ignore ConflictingContentLengthHeaders