SlevomatCodingStandard.Classes.DisallowStringExpressionPropertyFetch: New sniff that disallows string expression property fetch $object->{'foo'}

Author: kukulich

README.md

@@ -50,6 +50,7 @@ Slevomat Coding Standard for [PHP_CodeSniffer](https://github.com/squizlabs/PHP_
  - [SlevomatCodingStandard.Classes.DisallowLateStaticBindingForConstants](doc/classes.md#slevomatcodingstandardclassesdisallowlatestaticbindingforconstants-) 🔧
  - [SlevomatCodingStandard.Classes.DisallowMultiConstantDefinition](doc/classes.md#slevomatcodingstandardclassesdisallowmulticonstantdefinition-) 🔧
  - [SlevomatCodingStandard.Classes.DisallowMultiPropertyDefinition](doc/classes.md#slevomatcodingstandardclassesdisallowmultipropertydefinition-) 🔧
+ - [SlevomatCodingStandard.Classes.DisallowStringExpressionPropertyFetch](doc/classes.md#slevomatcodingstandardclassesdisallowstringexpressionpropertyfetch-) 🔧
  - [SlevomatCodingStandard.Classes.EmptyLinesAroundClassBraces](doc/classes.md#slevomatcodingstandardclassesemptylinesaroundclassbraces-) 🔧
  - [SlevomatCodingStandard.Classes.EnumCaseSpacing](doc/classes.md#slevomatcodingstandardclassesenumcasespacing-) 🔧
  - [SlevomatCodingStandard.Classes.ForbiddenPublicProperty](doc/classes.md#slevomatcodingstandardclassesforbiddenpublicproperty)

SlevomatCodingStandard/Sniffs/Classes/DisallowStringExpressionPropertyFetchSniff.php

@@ -0,0 +1,85 @@
+<?php declare(strict_types = 1);
+
+namespace SlevomatCodingStandard\Sniffs\Classes;
+
+use PHP_CodeSniffer\Files\File;
+use PHP_CodeSniffer\Sniffs\Sniff;
+use SlevomatCodingStandard\Helpers\FixerHelper;
+use SlevomatCodingStandard\Helpers\TokenHelper;
+use function preg_match;
+use const T_CONSTANT_ENCAPSED_STRING;
+use const T_OBJECT_OPERATOR;
+use const T_OPEN_CURLY_BRACKET;
+use const T_OPEN_PARENTHESIS;
+
+class DisallowStringExpressionPropertyFetchSniff implements Sniff
+{
+
+	public const CODE_DISALLOWED_STRING_EXPRESSION_PROPERTY_FETCH = 'DisallowedStringExpressionPropertyFetch';
+
+	/**
+	 * @return array<int, (int|string)>
+	 */
+	public function register(): array
+	{
+		return [T_OBJECT_OPERATOR];
+	}
+
+	/**
+	 * @phpcsSuppress SlevomatCodingStandard.TypeHints.ParameterTypeHint.MissingNativeTypeHint
+	 * @param int $objectOperatorPointer
+	 */
+	public function process(File $phpcsFile, $objectOperatorPointer): void
+	{
+		$tokens = $phpcsFile->getTokens();
+
+		$curlyBracketOpenerPointer = TokenHelper::findNextEffective($phpcsFile, $objectOperatorPointer + 1);
+
+		if ($tokens[$curlyBracketOpenerPointer]['code'] !== T_OPEN_CURLY_BRACKET) {
+			return;
+		}
+
+		$curlyBracketCloserPointer = $tokens[$curlyBracketOpenerPointer]['bracket_closer'];
+
+		if (TokenHelper::findNextExcluding(
+			$phpcsFile,
+			T_CONSTANT_ENCAPSED_STRING,
+			$curlyBracketOpenerPointer + 1,
+			$curlyBracketCloserPointer
+		) !== null) {
+			return;
+		}
+
+		$pointerAfterCurlyBracketCloser = TokenHelper::findNextEffective($phpcsFile, $curlyBracketCloserPointer + 1);
+
+		if ($tokens[$pointerAfterCurlyBracketCloser]['code'] === T_OPEN_PARENTHESIS) {
+			return;
+		}
+
+		if (preg_match(
+			'~^(["\'])([a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*)\1$~',
+			$tokens[$curlyBracketOpenerPointer + 1]['content'],
+			$matches
+		) !== 1) {
+			return;
+		}
+
+		$fix = $phpcsFile->addFixableError(
+			'String expression property fetch is disallowed, use identifier property fetch.',
+			$curlyBracketOpenerPointer,
+			self::CODE_DISALLOWED_STRING_EXPRESSION_PROPERTY_FETCH
+		);
+
+		if (!$fix) {
+			return;
+		}
+
+		$phpcsFile->fixer->beginChangeset();
+
+		$phpcsFile->fixer->replaceToken($curlyBracketOpenerPointer, $matches[2]);
+		FixerHelper::removeBetweenIncluding($phpcsFile, $curlyBracketOpenerPointer + 1, $curlyBracketCloserPointer);
+
+		$phpcsFile->fixer->endChangeset();
+	}
+
+}

doc/classes.md

@@ -113,6 +113,14 @@ Disallows multi constant definition.
 
 Disallows multi property definition.
 
+#### SlevomatCodingStandard.Classes.DisallowMultiPropertyDefinition 🔧
+
+Disallows multi property definition.
+
+#### SlevomatCodingStandard.Classes.DisallowStringExpressionPropertyFetch 🔧
+
+Disallows string expression property fetch `$object->{'foo'}` when the property name is compatible with identifier access.
+
 #### SlevomatCodingStandard.Classes.EmptyLinesAroundClassBraces 🔧
 
 Enforces one configurable number of lines after opening class/interface/trait brace and one empty line before the closing brace.

tests/Sniffs/Classes/DisallowStringExpressionPropertyFetchSniffTest.php

@@ -0,0 +1,29 @@
+<?php declare(strict_types = 1);
+
+namespace SlevomatCodingStandard\Sniffs\Classes;
+
+use SlevomatCodingStandard\Sniffs\TestCase;
+
+class DisallowStringExpressionPropertyFetchSniffTest extends TestCase
+{
+
+	public function testNoErrors(): void
+	{
+		$report = self::checkFile(__DIR__ . '/data/disallowStringExpressionPropertyFetchNoErrors.php');
+		self::assertNoSniffErrorInFile($report);
+	}
+
+	public function testErrors(): void
+	{
+		$report = self::checkFile(__DIR__ . '/data/disallowStringExpressionPropertyFetchErrors.php');
+
+		self::assertSame(3, $report->getErrorCount());
+
+		self::assertSniffError($report, 3, DisallowStringExpressionPropertyFetchSniff::CODE_DISALLOWED_STRING_EXPRESSION_PROPERTY_FETCH);
+		self::assertSniffError($report, 5, DisallowStringExpressionPropertyFetchSniff::CODE_DISALLOWED_STRING_EXPRESSION_PROPERTY_FETCH);
+		self::assertSniffError($report, 7, DisallowStringExpressionPropertyFetchSniff::CODE_DISALLOWED_STRING_EXPRESSION_PROPERTY_FETCH);
+
+		self::assertAllFixedInFile($report);
+	}
+
+}

tests/Sniffs/Classes/data/disallowStringExpressionPropertyFetchErrors.fixed.php

@@ -0,0 +1,7 @@
+<?php
+
+$a->foo;
+
+$a->boo;
+
+$a->foo_boo;

tests/Sniffs/Classes/data/disallowStringExpressionPropertyFetchErrors.php

@@ -0,0 +1,7 @@
+<?php
+
+$a->{'foo'};
+
+$a->{"boo"};
+
+$a->{"foo_boo"};

tests/Sniffs/Classes/data/disallowStringExpressionPropertyFetchNoErrors.php

@@ -0,0 +1,13 @@
+<?php
+
+$a->foo;
+
+$b->boo();
+
+$c->{'coo'}();
+
+$d->{'doo' . $c};
+
+if (isset($a->{'not-compatible'})) {
+
+}