From 4f8741c75eb44f4cf4131bdc91bb0fc28a0cfe54 Mon Sep 17 00:00:00 2001
From: Mike Letellier <mike@crabcyb.org>
Date: Tue, 13 Jan 2026 16:59:58 -0400
Subject: [PATCH] Add sniffs to catch redundant isset checks

---
 .../RedundantIssetBeforeNotEmptySniff.php     | 155 ++++++++++++++++++
 .../RedundantNotIssetBeforeEmptySniff.php     | 155 ++++++++++++++++++
 phpcs.xml                                     |  12 +-
 3 files changed, 317 insertions(+), 5 deletions(-)
 create mode 100644 phpcs-sniffs/Formidable/Sniffs/CodeAnalysis/RedundantIssetBeforeNotEmptySniff.php
 create mode 100644 phpcs-sniffs/Formidable/Sniffs/CodeAnalysis/RedundantNotIssetBeforeEmptySniff.php

diff --git a/phpcs-sniffs/Formidable/Sniffs/CodeAnalysis/RedundantIssetBeforeNotEmptySniff.php b/phpcs-sniffs/Formidable/Sniffs/CodeAnalysis/RedundantIssetBeforeNotEmptySniff.php
new file mode 100644
index 0000000000..6b2421f0a6
--- /dev/null
+++ b/phpcs-sniffs/Formidable/Sniffs/CodeAnalysis/RedundantIssetBeforeNotEmptySniff.php
@@ -0,0 +1,155 @@
+<?php
+/**
+ * Formidable_Sniffs_CodeAnalysis_RedundantIssetBeforeNotEmptySniff
+ *
+ * Detects redundant isset() checks before ! empty() on the same variable.
+ *
+ * @package Formidable\Sniffs
+ */
+
+namespace Formidable\Sniffs\CodeAnalysis;
+
+use PHP_CodeSniffer\Sniffs\Sniff;
+use PHP_CodeSniffer\Files\File;
+
+/**
+ * Detects and removes redundant isset() before ! empty() checks.
+ *
+ * Bad:
+ * isset( $var ) && ! empty( $var )
+ * isset( $array['key'] ) && ! empty( $array['key'] )
+ *
+ * Good:
+ * ! empty( $var )
+ * ! empty( $array['key'] )
+ *
+ * The empty() function already checks if a variable is set, so isset() is redundant.
+ */
+class RedundantIssetBeforeNotEmptySniff implements Sniff {
+
+	/**
+	 * Returns an array of tokens this test wants to listen for.
+	 *
+	 * @return array
+	 */
+	public function register() {
+		return array( T_ISSET );
+	}
+
+	/**
+	 * Processes this test, when one of its tokens is encountered.
+	 *
+	 * @param File $phpcsFile The file being scanned.
+	 * @param int  $stackPtr  The position of the current token in the stack passed in $tokens.
+	 *
+	 * @return void
+	 */
+	public function process( File $phpcsFile, $stackPtr ) {
+		$tokens = $phpcsFile->getTokens();
+
+		// Get the opening parenthesis of isset().
+		$issetOpen = $phpcsFile->findNext( T_WHITESPACE, $stackPtr + 1, null, true );
+
+		if ( false === $issetOpen || $tokens[ $issetOpen ]['code'] !== T_OPEN_PARENTHESIS ) {
+			return;
+		}
+
+		// Get the closing parenthesis of isset().
+		if ( ! isset( $tokens[ $issetOpen ]['parenthesis_closer'] ) ) {
+			return;
+		}
+
+		$issetClose = $tokens[ $issetOpen ]['parenthesis_closer'];
+
+		// Get the variable expression inside isset().
+		$issetVarContent = $this->getParenthesesContent( $phpcsFile, $issetOpen, $issetClose );
+
+		// Find the && operator after isset().
+		$andOperator = $phpcsFile->findNext( T_WHITESPACE, $issetClose + 1, null, true );
+
+		if ( false === $andOperator || $tokens[ $andOperator ]['code'] !== T_BOOLEAN_AND ) {
+			return;
+		}
+
+		// Find the ! (boolean not) after &&.
+		$notOperator = $phpcsFile->findNext( T_WHITESPACE, $andOperator + 1, null, true );
+
+		if ( false === $notOperator || $tokens[ $notOperator ]['code'] !== T_BOOLEAN_NOT ) {
+			return;
+		}
+
+		// Find empty() after the !.
+		$emptyToken = $phpcsFile->findNext( T_WHITESPACE, $notOperator + 1, null, true );
+
+		if ( false === $emptyToken || $tokens[ $emptyToken ]['code'] !== T_EMPTY ) {
+			return;
+		}
+
+		// Get the opening parenthesis of empty().
+		$emptyOpen = $phpcsFile->findNext( T_WHITESPACE, $emptyToken + 1, null, true );
+
+		if ( false === $emptyOpen || $tokens[ $emptyOpen ]['code'] !== T_OPEN_PARENTHESIS ) {
+			return;
+		}
+
+		// Get the closing parenthesis of empty().
+		if ( ! isset( $tokens[ $emptyOpen ]['parenthesis_closer'] ) ) {
+			return;
+		}
+
+		$emptyClose = $tokens[ $emptyOpen ]['parenthesis_closer'];
+
+		// Get the variable expression inside empty().
+		$emptyVarContent = $this->getParenthesesContent( $phpcsFile, $emptyOpen, $emptyClose );
+
+		// Check if the variables match.
+		if ( $issetVarContent !== $emptyVarContent ) {
+			return;
+		}
+
+		$fix = $phpcsFile->addFixableError(
+			'Redundant isset() before ! empty(). The empty() function already checks if a variable is set. Use "! empty( %s )" instead.',
+			$stackPtr,
+			'Found',
+			array( $issetVarContent )
+		);
+
+		if ( true === $fix ) {
+			$phpcsFile->fixer->beginChangeset();
+
+			// Remove isset( $var ) &&.
+			// Find the end of the && operator (including trailing whitespace).
+			$removeEnd = $phpcsFile->findNext( T_WHITESPACE, $andOperator + 1, null, true );
+
+			// Remove all tokens from isset to just before the !.
+			for ( $i = $stackPtr; $i < $removeEnd; $i++ ) {
+				$phpcsFile->fixer->replaceToken( $i, '' );
+			}
+
+			$phpcsFile->fixer->endChangeset();
+		}
+	}
+
+	/**
+	 * Get the content inside parentheses (excluding the parentheses themselves).
+	 *
+	 * @param File $phpcsFile  The file being scanned.
+	 * @param int  $openParen  The position of the opening parenthesis.
+	 * @param int  $closeParen The position of the closing parenthesis.
+	 *
+	 * @return string
+	 */
+	private function getParenthesesContent( File $phpcsFile, $openParen, $closeParen ) {
+		$tokens  = $phpcsFile->getTokens();
+		$content = '';
+
+		for ( $i = $openParen + 1; $i < $closeParen; $i++ ) {
+			// Skip whitespace for comparison purposes.
+			if ( $tokens[ $i ]['code'] !== T_WHITESPACE ) {
+				$content .= $tokens[ $i ]['content'];
+			}
+		}
+
+		return $content;
+	}
+}
diff --git a/phpcs-sniffs/Formidable/Sniffs/CodeAnalysis/RedundantNotIssetBeforeEmptySniff.php b/phpcs-sniffs/Formidable/Sniffs/CodeAnalysis/RedundantNotIssetBeforeEmptySniff.php
new file mode 100644
index 0000000000..3feb583ca3
--- /dev/null
+++ b/phpcs-sniffs/Formidable/Sniffs/CodeAnalysis/RedundantNotIssetBeforeEmptySniff.php
@@ -0,0 +1,155 @@
+<?php
+/**
+ * Formidable_Sniffs_CodeAnalysis_RedundantNotIssetBeforeEmptySniff
+ *
+ * Detects redundant ! isset() checks before empty() on the same variable.
+ *
+ * @package Formidable\Sniffs
+ */
+
+namespace Formidable\Sniffs\CodeAnalysis;
+
+use PHP_CodeSniffer\Sniffs\Sniff;
+use PHP_CodeSniffer\Files\File;
+
+/**
+ * Detects and removes redundant ! isset() before empty() checks.
+ *
+ * Bad:
+ * ! isset( $var ) || empty( $var )
+ * ! isset( $array['key'] ) || empty( $array['key'] )
+ *
+ * Good:
+ * empty( $var )
+ * empty( $array['key'] )
+ *
+ * The empty() function already checks if a variable is set, so ! isset() is redundant.
+ */
+class RedundantNotIssetBeforeEmptySniff implements Sniff {
+
+	/**
+	 * Returns an array of tokens this test wants to listen for.
+	 *
+	 * @return array
+	 */
+	public function register() {
+		return array( T_BOOLEAN_NOT );
+	}
+
+	/**
+	 * Processes this test, when one of its tokens is encountered.
+	 *
+	 * @param File $phpcsFile The file being scanned.
+	 * @param int  $stackPtr  The position of the current token in the stack passed in $tokens.
+	 *
+	 * @return void
+	 */
+	public function process( File $phpcsFile, $stackPtr ) {
+		$tokens = $phpcsFile->getTokens();
+
+		// Find isset() after the !.
+		$issetToken = $phpcsFile->findNext( T_WHITESPACE, $stackPtr + 1, null, true );
+
+		if ( false === $issetToken || $tokens[ $issetToken ]['code'] !== T_ISSET ) {
+			return;
+		}
+
+		// Get the opening parenthesis of isset().
+		$issetOpen = $phpcsFile->findNext( T_WHITESPACE, $issetToken + 1, null, true );
+
+		if ( false === $issetOpen || $tokens[ $issetOpen ]['code'] !== T_OPEN_PARENTHESIS ) {
+			return;
+		}
+
+		// Get the closing parenthesis of isset().
+		if ( ! isset( $tokens[ $issetOpen ]['parenthesis_closer'] ) ) {
+			return;
+		}
+
+		$issetClose = $tokens[ $issetOpen ]['parenthesis_closer'];
+
+		// Get the variable expression inside isset().
+		$issetVarContent = $this->getParenthesesContent( $phpcsFile, $issetOpen, $issetClose );
+
+		// Find the || operator after isset().
+		$orOperator = $phpcsFile->findNext( T_WHITESPACE, $issetClose + 1, null, true );
+
+		if ( false === $orOperator || $tokens[ $orOperator ]['code'] !== T_BOOLEAN_OR ) {
+			return;
+		}
+
+		// Find empty() after ||.
+		$emptyToken = $phpcsFile->findNext( T_WHITESPACE, $orOperator + 1, null, true );
+
+		if ( false === $emptyToken || $tokens[ $emptyToken ]['code'] !== T_EMPTY ) {
+			return;
+		}
+
+		// Get the opening parenthesis of empty().
+		$emptyOpen = $phpcsFile->findNext( T_WHITESPACE, $emptyToken + 1, null, true );
+
+		if ( false === $emptyOpen || $tokens[ $emptyOpen ]['code'] !== T_OPEN_PARENTHESIS ) {
+			return;
+		}
+
+		// Get the closing parenthesis of empty().
+		if ( ! isset( $tokens[ $emptyOpen ]['parenthesis_closer'] ) ) {
+			return;
+		}
+
+		$emptyClose = $tokens[ $emptyOpen ]['parenthesis_closer'];
+
+		// Get the variable expression inside empty().
+		$emptyVarContent = $this->getParenthesesContent( $phpcsFile, $emptyOpen, $emptyClose );
+
+		// Check if the variables match.
+		if ( $issetVarContent !== $emptyVarContent ) {
+			return;
+		}
+
+		$fix = $phpcsFile->addFixableError(
+			'Redundant ! isset() before empty(). The empty() function already checks if a variable is set. Use "empty( %s )" instead.',
+			$stackPtr,
+			'Found',
+			array( $issetVarContent )
+		);
+
+		if ( true === $fix ) {
+			$phpcsFile->fixer->beginChangeset();
+
+			// Remove ! isset( $var ) ||.
+			// Find the start of empty() (the token after ||).
+			$removeEnd = $phpcsFile->findNext( T_WHITESPACE, $orOperator + 1, null, true );
+
+			// Remove all tokens from ! to just before empty().
+			for ( $i = $stackPtr; $i < $removeEnd; $i++ ) {
+				$phpcsFile->fixer->replaceToken( $i, '' );
+			}
+
+			$phpcsFile->fixer->endChangeset();
+		}
+	}
+
+	/**
+	 * Get the content inside parentheses (excluding the parentheses themselves).
+	 *
+	 * @param File $phpcsFile  The file being scanned.
+	 * @param int  $openParen  The position of the opening parenthesis.
+	 * @param int  $closeParen The position of the closing parenthesis.
+	 *
+	 * @return string
+	 */
+	private function getParenthesesContent( File $phpcsFile, $openParen, $closeParen ) {
+		$tokens  = $phpcsFile->getTokens();
+		$content = '';
+
+		for ( $i = $openParen + 1; $i < $closeParen; $i++ ) {
+			// Skip whitespace for comparison purposes.
+			if ( $tokens[ $i ]['code'] !== T_WHITESPACE ) {
+				$content .= $tokens[ $i ]['content'];
+			}
+		}
+
+		return $content;
+	}
+}
diff --git a/phpcs.xml b/phpcs.xml
index ea7e8302d6..f695b67445 100644
--- a/phpcs.xml
+++ b/phpcs.xml
@@ -239,18 +239,20 @@
 
 	<!-- Code Analysis -->
 	<rule ref="Formidable.CodeAnalysis.SimplifyIfReturn" />
-	<rule ref="Formidable.CodeAnalysis.PreferObGetClean" />
+	<rule ref="Formidable.CodeAnalysis.SimplifyIssetFalsyCheck" />
+	<rule ref="Formidable.CodeAnalysis.SimplifyIssetTruthyCheck" />
+	<rule ref="Formidable.CodeAnalysis.SimplifyIssetEmptyCheck" />
 	<rule ref="Formidable.CodeAnalysis.RedundantEmptyOnParameter" />
 	<rule ref="Formidable.CodeAnalysis.RedundantEmptyOnAssignedVariable" />
 	<rule ref="Formidable.CodeAnalysis.RedundantParentheses" />
 	<rule ref="Formidable.CodeAnalysis.RedundantIconEchoArg" />
-	<rule ref="Formidable.CodeAnalysis.SimplifyIssetFalsyCheck" />
-	<rule ref="Formidable.CodeAnalysis.SimplifyIssetTruthyCheck" />
-	<rule ref="Formidable.CodeAnalysis.SimplifyIssetEmptyCheck" />
+	<rule ref="Formidable.CodeAnalysis.RedundantTruthyBeforeStringComparison" />
+	<rule ref="Formidable.CodeAnalysis.RedundantIssetBeforeNotEmpty" />
+	<rule ref="Formidable.CodeAnalysis.RedundantNotIssetBeforeEmpty" />
 	<rule ref="Formidable.CodeAnalysis.PreferKsesEcho" />
 	<rule ref="Formidable.CodeAnalysis.MoveVariableBelowEarlyReturn" />
 	<rule ref="Formidable.CodeAnalysis.FlipNegativeTernary" />
-	<rule ref="Formidable.CodeAnalysis.RedundantTruthyBeforeStringComparison" />
 	<rule ref="Formidable.CodeAnalysis.PreferStrictComparison" />
 	<rule ref="Formidable.CodeAnalysis.PreferStrictInArray" />
+	<rule ref="Formidable.CodeAnalysis.PreferObGetClean" />
 </ruleset>