PregSplitCaptureFlagWithoutGroups

info native on by default quick-fix

Group: Probable bugs

Detect preg_split with PREG_SPLIT_DELIM_CAPTURE on a parsed literal regex containing no capturing groups.

Example

Before

<?php
$parts=preg_split('/,/',$text,-1,PREG_SPLIT_DELIM_CAPTURE);

After fix

<?php
$parts=preg_split('/,/',$text,-1,0);

Reported:

• line 2: Remove the capture flag or add a capturing group.

Detection

• Report preg_split with PREG_SPLIT_DELIM_CAPTURE on a parsed literal regex containing no capturing groups.
• 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)

• Named or numbered captures, unknown regex/flags, and branch-reset captures are excluded.
• 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

Remove the ineffective flag only when flags are a sole constant or a side-effect-free bitwise-or tree; use zero for an otherwise empty flags argument.

A fix is offered only when the concrete prerequisites above are proven. Edits use exact source byte ranges, preserve comments and argument evaluation order, and introduce syntax supported by the configured PHP version. Never invent error-handling policy.

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": {
    "PregSplitCaptureFlagWithoutGroups": {
      "enabled": false
    }
  }
}

Suppress

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

// @custos-ignore PregSplitCaptureFlagWithoutGroups