UselessIfConditionWithReturnSniff.php

<?php

declare (strict_types=1);
namespace SlevomatCodingStandard\Sniffs\ControlStructures;

use PHP_CodeSniffer\Files\File;
use PHP_CodeSniffer\Sniffs\Sniff;
use PHP_CodeSniffer\Util\Tokens;
use SlevomatCodingStandard\Helpers\ConditionHelper;
use SlevomatCodingStandard\Helpers\FixerHelper;
use SlevomatCodingStandard\Helpers\TokenHelper;
use function array_key_exists;
use function in_array;
use function sprintf;
use function strtolower;
use const T_ELSE;
use const T_FALSE;
use const T_IF;
use const T_RETURN;
use const T_SEMICOLON;
use const T_TRUE;
class UselessIfConditionWithReturnSniff implements Sniff {
    public const CODE_USELESS_IF_CONDITION = 'UselessIfCondition';
    
    /** @var bool */
    public $assumeAllConditionExpressionsAreAlreadyBoolean = false;
    
    /**
     * @return array<int, (int|string)>
     */
    public function register() : array {
        return [
            T_IF,
        ];
    }
    
    /**
     * @phpcsSuppress SlevomatCodingStandard.TypeHints.ParameterTypeHint.MissingNativeTypeHint
     * @param int $ifPointer
     */
    public function process(File $phpcsFile, $ifPointer) : void {
        $tokens = $phpcsFile->getTokens();
        if (!array_key_exists('scope_closer', $tokens[$ifPointer])) {
            // If without curly braces is not supported.
            return;
        }
        $ifBooleanPointer = $this->findBooleanAfterReturnInScope($phpcsFile, $tokens[$ifPointer]['scope_opener']);
        if ($ifBooleanPointer === null) {
            return;
        }
        $newCondition = static function () use ($phpcsFile, $tokens, $ifBooleanPointer, $ifPointer) : string {
            return strtolower($tokens[$ifBooleanPointer]['content']) === 'true' ? TokenHelper::getContent($phpcsFile, $tokens[$ifPointer]['parenthesis_opener'] + 1, $tokens[$ifPointer]['parenthesis_closer'] - 1) : ConditionHelper::getNegativeCondition($phpcsFile, $tokens[$ifPointer]['parenthesis_opener'] + 1, $tokens[$ifPointer]['parenthesis_closer'] - 1);
        };
        $elsePointer = TokenHelper::findNextEffective($phpcsFile, $tokens[$ifPointer]['scope_closer'] + 1);
        $errorParameters = [
            'Useless condition.',
            $ifPointer,
            self::CODE_USELESS_IF_CONDITION,
        ];
        if ($elsePointer !== null && $tokens[$elsePointer]['code'] === T_ELSE) {
            if (!array_key_exists('scope_closer', $tokens[$elsePointer])) {
                // Else without curly braces is not supported.
                return;
            }
            $elseBooleanPointer = $this->findBooleanAfterReturnInScope($phpcsFile, $tokens[$elsePointer]['scope_opener']);
            if ($elseBooleanPointer === null) {
                return;
            }
            if (!$this->isFixable($phpcsFile, $ifPointer, $tokens[$elsePointer]['scope_closer'])) {
                $phpcsFile->addError(...$errorParameters);
                return;
            }
            $fix = $phpcsFile->addFixableError(...$errorParameters);
            if (!$fix) {
                return;
            }
            $phpcsFile->fixer
                ->beginChangeset();
            FixerHelper::change($phpcsFile, $ifPointer, $tokens[$elsePointer]['scope_closer'], sprintf('return %s;', $newCondition()));
            $phpcsFile->fixer
                ->endChangeset();
        }
        else {
            $returnPointer = TokenHelper::findNextEffective($phpcsFile, $tokens[$ifPointer]['scope_closer'] + 1);
            if ($returnPointer === null) {
                return;
            }
            if ($tokens[$returnPointer]['code'] !== T_RETURN) {
                return;
            }
            $semicolonPointer = $this->findSemicolonAfterReturnWithBoolean($phpcsFile, $returnPointer);
            if ($semicolonPointer === null) {
                return;
            }
            if (!$this->isFixable($phpcsFile, $ifPointer, $semicolonPointer)) {
                $phpcsFile->addError(...$errorParameters);
                return;
            }
            $fix = $phpcsFile->addFixableError(...$errorParameters);
            if (!$fix) {
                return;
            }
            $phpcsFile->fixer
                ->beginChangeset();
            FixerHelper::change($phpcsFile, $ifPointer, $semicolonPointer, sprintf('return %s;', $newCondition()));
            $phpcsFile->fixer
                ->endChangeset();
        }
    }
    private function isFixable(File $phpcsFile, int $ifPointer, int $endPointer) : bool {
        $tokens = $phpcsFile->getTokens();
        if (TokenHelper::findNext($phpcsFile, Tokens::$commentTokens, $ifPointer + 1, $endPointer) !== null) {
            return false;
        }
        if ($this->assumeAllConditionExpressionsAreAlreadyBoolean) {
            return true;
        }
        return ConditionHelper::conditionReturnsBoolean($phpcsFile, $tokens[$ifPointer]['parenthesis_opener'] + 1, $tokens[$ifPointer]['parenthesis_closer'] - 1);
    }
    private function findBooleanAfterReturnInScope(File $phpcsFile, int $scopeOpenerPointer) : ?int {
        $tokens = $phpcsFile->getTokens();
        
        /** @var int $returnPointer */
        $returnPointer = TokenHelper::findNextEffective($phpcsFile, $scopeOpenerPointer + 1);
        if ($tokens[$returnPointer]['code'] !== T_RETURN) {
            return null;
        }
        $booleanPointer = $this->findBooleanAfterReturn($phpcsFile, $returnPointer);
        if ($booleanPointer === null) {
            return null;
        }
        $semicolonPointer = TokenHelper::findNextEffective($phpcsFile, $booleanPointer + 1);
        if ($tokens[$semicolonPointer]['code'] !== T_SEMICOLON) {
            return null;
        }
        return $booleanPointer;
    }
    private function findBooleanAfterReturn(File $phpcsFile, int $returnPointer) : ?int {
        $tokens = $phpcsFile->getTokens();
        $booleanPointer = TokenHelper::findNextEffective($phpcsFile, $returnPointer + 1);
        if (in_array($tokens[$booleanPointer]['code'], [
            T_TRUE,
            T_FALSE,
        ], true)) {
            return $booleanPointer;
        }
        return null;
    }
    private function findSemicolonAfterReturnWithBoolean(File $phpcsFile, int $returnPointer) : ?int {
        $tokens = $phpcsFile->getTokens();
        $booleanPointer = $this->findBooleanAfterReturn($phpcsFile, $returnPointer);
        if ($booleanPointer === null) {
            return null;
        }
        $semicolonPointer = TokenHelper::findNextEffective($phpcsFile, $booleanPointer + 1);
        if ($tokens[$semicolonPointer]['code'] !== T_SEMICOLON) {
            return null;
        }
        return $semicolonPointer;
    }

}