NonBlockingEmptyReadTreatedAsEof

warning native on by default

Group: Probable bugs

An empty nonblocking read can mean that no data is currently available. Check EOF separately before closing the stream.

Example

<?php
$h=tmpfile();stream_set_blocking($h,false);if(fread($h,4096)===""){fclose($h);}

Reported:

• line 2: Check EOF separately from an empty nonblocking read.

Detection

• Resolved stream_set_blocking(handle,false) establishes nonblocking mode; condition strictly compares fread(sameHandle) result to empty string and branch closes that handle, without feof guard. Highlight equality.
• 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.
• 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": {
    "NonBlockingEmptyReadTreatedAsEof": {
      "enabled": false
    }
  }
}

Suppress

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

// @custos-ignore NonBlockingEmptyReadTreatedAsEof