Add three new sniffs for LearnDash coding standards

[nikolaystrikhar]

Summary

This PR adds two new sniffs to enforce LearnDash coding standards:

1. DisallowNonPrivateConstSniff - Prevents public/protected class constants
2. MultilineConditionFormattingSniff - Enforces proper multiline condition formatting

All sniffs are auto-fixable with phpcbf.

---

1. LearnDash.Classes.DisallowNonPrivateConst

Purpose

Public and protected class constants cannot be deprecated, so we should use static properties instead to allow for future deprecation.

What it catches

// ❌ ERROR: Public class constant
class Example {
    public const MY_CONST = 'value';
}

// ❌ ERROR: Protected class constant
class Example {
    protected const MY_CONST = 'value';
}

// ❌ ERROR: Implicit public (no visibility keyword)
class Example {
    const MY_CONST = 'value';
}

// ❌ ERROR: Interface constants (always implicitly public)
interface Example {
    const MY_CONST = 'value';
}

What passes

// ✅ OK: Private class constant
class Example {
    private const MY_CONST = 'value';
}

// ✅ OK: Global constants (not in a class)
const GLOBAL_CONST = 'value';

Error codes

• PublicConst - Explicit public constant
• ProtectedConst - Protected constant
• ImplicitPublicConst - Constant without visibility modifier

---

2. LearnDash.CodeAnalysis.MultilineConditionFormatting

Purpose

When conditions have multiple boolean expressions, they should be formatted for readability:

• Each condition on its own line
• Boolean operators (&&, ||) at the beginning of lines, not the end
• Remove unnecessary parentheses around single conditions
• Applies recursively to nested sub-conditions

What it catches

// ❌ ERROR: Multiple conditions on single line
if ( $a && $b || $c ) {
    // ...
}

// ❌ ERROR: Operator at END of line
if (
    $a &&
    $b
) {
    // ...
}

// ❌ ERROR: Unnecessary parentheses around single condition
if (
    ( ! empty( $a ) )
    && ( ! empty( $b ) )
) {
    // ...
}

// ❌ ERROR: Nested with operators at end
if (
    $a &&
    (
        $b ||
        $c
    )
) {
    // ...
}

What passes (after auto-fix)

// ✅ OK: Single condition on one line
if ( $a ) {
    // ...
}

// ✅ OK: Multiline with operators at start
if (
    $a
    && $b
    || $c
) {
    // ...
}

// ✅ OK: No unnecessary parentheses
if (
    ! empty( $a )
    && ! empty( $b )
) {
    // ...
}

// ✅ OK: Nested conditions properly formatted
if (
    $a
    && (
        $b
        || $c
    )
) {
    // ...
}

// ✅ OK: Four levels deep
if (
    $a
    && (
        $b
        || (
            $c
            && (
                $d
                || $e
            )
        )
    )
) {
    // ...
}

Error codes

• SingleLineMultipleConditions - Multiple boolean expressions on a single line
• OperatorNotAtLineStart - Boolean operator appears after other code on the same line
• UnnecessaryParentheses - Parentheses around a single condition with no boolean operators

Supported control structures

• if
• elseif
• while
• for
• switch

---

Usage

Add to your phpcs.xml:

<rule ref="LearnDash.Classes.DisallowNonPrivateConst"/>
<rule ref="LearnDash.CodeAnalysis.MultilineConditionFormatting"/>

Or run individually:

phpcs --standard=LearnDash --sniffs=LearnDash.Classes.DisallowNonPrivateConst src/
phpcs --standard=LearnDash --sniffs=LearnDash.CodeAnalysis.MultilineConditionFormatting src/

Test cases verified

MultilineConditionFormattingSniff

Before	After	Issue Fixed
if ( $a && $b || $c )	Split to multiline	Single line multi-condition
$a && $b	$a && $b	Operator at end of line
( ! empty( $a ) )	! empty( $a )	Unnecessary parentheses
Nested ( $b || $c ) with && at end	Properly indented, operators at start	Nested formatting
while ( $a && $b )	Split to multiline	While loop support
elseif ( $a && $b )	Split to multiline	Elseif support
4 levels deep nesting	Each level properly indented with tabs	Deep nesting support

Test plan

• DisallowNonPrivateConstSniff catches public, protected, and implicit public constants
• DisallowNonPrivateConstSniff allows private constants and global constants
• MultilineConditionFormattingSniff catches single-line multi-conditions
• MultilineConditionFormattingSniff catches operators at end of lines
• MultilineConditionFormattingSniff catches unnecessary parentheses
• MultilineConditionFormattingSniff works recursively on nested sub-conditions (up to 4+ levels)
• MultilineConditionFormattingSniff works with while, elseif, for, switch
• MultilineConditionFormattingSniff auto-fix produces consistent tab indentation (no mixed spaces/tabs)
• All sniffs properly register with PHPCS

🤖 Generated with Claude Code

[d4mation]

This check is too loose and results in false positives on text like

esc_html( learndash_get_custom_label_lower( 'groups' ) ),

[nikolaystrikhar]

There is a huge problem with it though, how do we decide which context is right and wrong and maintain it easily? Imagine I skip one case and then it becomes problematic to update again, we add more functions... I don't like the maintainability aspect of this sniff. Maybe it was a bad idea and we just delete it. Thoughts @estevao90 @d4mation ?

[d4mation]

warnings don't cause CI to fail, so maybe we should use error instead? The other existing sniffs all use error.

[nikolaystrikhar]

Fair!

[d4mation]

We may want an additional check to try to remove unnecessary parenthesis like this:

if (
	( ! empty( $this->transient_data['result_count'] ) )
	&& ( ! empty( $this->transient_data['total_count'] ) )
	&& ( $this->transient_data['result_count'] !== $this->transient_data['total_count'] )
) {

[nikolaystrikhar]

Addressed, good idea! One note though, we can't fully trust it and should always check how it changes the code.

[nikolaystrikhar]

I found some issues with indents and fixed them btw (it was mixing spaces and tabs)