Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
| 1 | <?php |
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| 21 | class NewInterfacesSniff extends AbstractNewFeatureSniff |
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| 22 | { |
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| 23 | |||
| 24 | /** |
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| 25 | * A list of new interfaces, not present in older versions. |
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| 26 | * |
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| 27 | * The array lists : version number with false (not present) or true (present). |
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| 28 | * If's sufficient to list the first version where the interface appears. |
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| 29 | * |
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| 30 | * @var array(string => array(string => int|string|null)) |
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| 31 | */ |
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| 32 | protected $newInterfaces = array( |
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| 33 | 'Traversable' => array( |
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| 34 | '4.4' => false, |
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| 35 | '5.0' => true, |
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| 36 | ), |
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| 37 | 'Reflector' => array( |
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| 38 | '4.4' => false, |
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| 39 | '5.0' => true, |
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| 40 | ), |
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| 41 | |||
| 42 | 'Countable' => array( |
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| 43 | '5.0' => false, |
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| 44 | '5.1' => true, |
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| 45 | ), |
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| 46 | 'OuterIterator' => array( |
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| 47 | '5.0' => false, |
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| 48 | '5.1' => true, |
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| 49 | ), |
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| 50 | 'RecursiveIterator' => array( |
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| 51 | '5.0' => false, |
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| 52 | '5.1' => true, |
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| 53 | ), |
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| 54 | 'SeekableIterator' => array( |
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| 55 | '5.0' => false, |
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| 56 | '5.1' => true, |
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| 57 | ), |
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| 58 | 'Serializable' => array( |
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| 59 | '5.0' => false, |
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| 60 | '5.1' => true, |
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| 61 | ), |
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| 62 | 'SplObserver' => array( |
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| 63 | '5.0' => false, |
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| 64 | '5.1' => true, |
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| 65 | ), |
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| 66 | 'SplSubject' => array( |
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| 67 | '5.0' => false, |
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| 68 | '5.1' => true, |
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| 69 | ), |
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| 70 | |||
| 71 | 'JsonSerializable' => array( |
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| 72 | '5.3' => false, |
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| 73 | '5.4' => true, |
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| 74 | ), |
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| 75 | 'SessionHandlerInterface' => array( |
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| 76 | '5.3' => false, |
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| 77 | '5.4' => true, |
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| 78 | ), |
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| 79 | |||
| 80 | 'DateTimeInterface' => array( |
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| 81 | '5.4' => false, |
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| 82 | '5.5' => true, |
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| 83 | ), |
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| 84 | |||
| 85 | 'Throwable' => array( |
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| 86 | '5.6' => false, |
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| 87 | '7.0' => true, |
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| 88 | ), |
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| 89 | |||
| 90 | ); |
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| 91 | |||
| 92 | /** |
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| 93 | * A list of methods which cannot be used in combination with particular interfaces. |
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| 94 | * |
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| 95 | * @var array(string => array(string => string)) |
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| 96 | */ |
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| 97 | protected $unsupportedMethods = array( |
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| 98 | 'Serializable' => array( |
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| 99 | '__sleep' => 'http://php.net/serializable', |
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| 100 | '__wakeup' => 'http://php.net/serializable', |
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| 101 | ), |
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| 102 | ); |
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| 103 | |||
| 104 | /** |
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| 105 | * Returns an array of tokens this test wants to listen for. |
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| 106 | * |
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| 107 | * @return array |
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| 108 | */ |
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| 109 | public function register() |
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| 132 | |||
| 133 | |||
| 134 | /** |
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| 135 | * Processes this test, when one of its tokens is encountered. |
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| 136 | * |
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| 137 | * @param \PHP_CodeSniffer_File $phpcsFile The file being scanned. |
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| 138 | * @param int $stackPtr The position of the current token in |
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| 139 | * the stack passed in $tokens. |
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| 140 | * |
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| 141 | * @return void |
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| 142 | */ |
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| 143 | View Code Duplication | public function process(\PHP_CodeSniffer_File $phpcsFile, $stackPtr) |
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| 144 | { |
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| 145 | $tokens = $phpcsFile->getTokens(); |
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| 146 | |||
| 147 | switch ($tokens[$stackPtr]['type']) { |
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| 148 | case 'T_CLASS': |
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| 149 | case 'T_ANON_CLASS': |
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| 150 | $this->processClassToken($phpcsFile, $stackPtr); |
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| 151 | break; |
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| 152 | |||
| 153 | case 'T_FUNCTION': |
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| 154 | case 'T_CLOSURE': |
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| 155 | $this->processFunctionToken($phpcsFile, $stackPtr); |
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| 156 | |||
| 157 | // Deal with older PHPCS versions which don't recognize return type hints. |
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| 158 | $returnTypeHint = $this->getReturnTypeHintToken($phpcsFile, $stackPtr); |
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| 159 | if ($returnTypeHint !== false) { |
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| 160 | $this->processReturnTypeToken($phpcsFile, $returnTypeHint); |
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| 161 | } |
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| 162 | break; |
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| 163 | |||
| 164 | case 'T_RETURN_TYPE': |
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| 165 | $this->processReturnTypeToken($phpcsFile, $stackPtr); |
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| 166 | break; |
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| 167 | |||
| 168 | default: |
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| 169 | // Deliberately left empty. |
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| 170 | break; |
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| 171 | } |
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| 172 | |||
| 173 | }//end process() |
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| 174 | |||
| 175 | |||
| 176 | /** |
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| 177 | * Processes this test for when a class token is encountered. |
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| 178 | * |
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| 179 | * - Detect classes implementing the new interfaces. |
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| 180 | * - Detect classes implementing the new interfaces with unsupported functions. |
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| 181 | * |
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| 182 | * @param \PHP_CodeSniffer_File $phpcsFile The file being scanned. |
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| 183 | * @param int $stackPtr The position of the current token in |
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| 184 | * the stack passed in $tokens. |
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| 185 | * |
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| 186 | * @return void |
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| 187 | */ |
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| 188 | private function processClassToken(\PHP_CodeSniffer_File $phpcsFile, $stackPtr) |
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| 239 | |||
| 240 | |||
| 241 | /** |
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| 242 | * Processes this test for when a function token is encountered. |
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| 243 | * |
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| 244 | * - Detect new interfaces when used as a type hint. |
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| 245 | * |
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| 246 | * @param \PHP_CodeSniffer_File $phpcsFile The file being scanned. |
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| 247 | * @param int $stackPtr The position of the current token in |
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| 248 | * the stack passed in $tokens. |
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| 249 | * |
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| 250 | * @return void |
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| 251 | */ |
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| 252 | View Code Duplication | private function processFunctionToken(\PHP_CodeSniffer_File $phpcsFile, $stackPtr) |
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| 272 | |||
| 273 | |||
| 274 | /** |
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| 275 | * Processes this test for when a return type token is encountered. |
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| 276 | * |
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| 277 | * - Detect new interfaces when used as a return type declaration. |
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| 278 | * |
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| 279 | * @param \PHP_CodeSniffer_File $phpcsFile The file being scanned. |
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| 280 | * @param int $stackPtr The position of the current token in |
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| 281 | * the stack passed in $tokens. |
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| 282 | * |
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| 283 | * @return void |
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| 284 | */ |
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| 285 | View Code Duplication | private function processReturnTypeToken(\PHP_CodeSniffer_File $phpcsFile, $stackPtr) |
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| 286 | { |
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| 287 | $returnTypeHint = $this->getReturnTypeHintName($phpcsFile, $stackPtr); |
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| 288 | $returnTypeHint = ltrim($returnTypeHint, '\\'); |
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| 289 | $returnTypeHintLc = strtolower($returnTypeHint); |
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| 290 | |||
| 291 | if (isset($this->newInterfaces[$returnTypeHintLc]) === false) { |
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| 292 | return; |
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| 293 | } |
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| 294 | |||
| 295 | // Still here ? Then this is a return type declaration using a new interface. |
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| 296 | $itemInfo = array( |
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| 297 | 'name' => $returnTypeHint, |
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| 298 | 'nameLc' => $returnTypeHintLc, |
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| 299 | ); |
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| 300 | $this->handleFeature($phpcsFile, $stackPtr, $itemInfo); |
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| 301 | } |
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| 302 | |||
| 303 | |||
| 304 | /** |
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| 305 | * Get the relevant sub-array for a specific item from a multi-dimensional array. |
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| 306 | * |
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| 307 | * @param array $itemInfo Base information about the item. |
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| 308 | * |
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| 309 | * @return array Version and other information about the item. |
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| 310 | */ |
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| 311 | public function getItemArray(array $itemInfo) |
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| 315 | |||
| 316 | |||
| 317 | /** |
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| 318 | * Get the error message template for this sniff. |
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| 319 | * |
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| 320 | * @return string |
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| 321 | */ |
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| 322 | protected function getErrorMsgTemplate() |
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| 326 | |||
| 327 | |||
| 328 | }//end class |
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| 329 |
If you define a variable conditionally, it can happen that it is not defined for all execution paths.
Let’s take a look at an example:
In the above example, the variable $x is defined if you pass “foo” or “bar” as argument for $a. However, since the switch statement has no default case statement, if you pass any other value, the variable $x would be undefined.
Available Fixes
Check for existence of the variable explicitly:
Define a default value for the variable:
Add a value for the missing path: