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:
Complex classes like Parser often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use Parser, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 26 | class Parser extends Tokenizer |
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| 27 | { |
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| 28 | |||
| 29 | /** @var array */ |
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| 30 | private $data = []; |
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| 31 | |||
| 32 | 96 | public function parse($source = null) |
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| 33 | { |
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| 34 | 96 | $this->init($source); |
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| 35 | |||
| 36 | 96 | while (!$this->end()) { |
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| 37 | 95 | $tokenType = $this->peek()->getType(); |
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| 38 | |||
| 39 | switch ($tokenType) { |
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| 40 | 95 | case Token::TYPE_LBRACE: |
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| 41 | 44 | case Token::TYPE_QUERY: |
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| 42 | 78 | foreach ($this->parseBody() as $query) { |
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| 43 | 71 | $this->data['queries'][] = $query; |
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| 44 | } |
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| 45 | |||
| 46 | 74 | break; |
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| 47 | |||
| 48 | 25 | case Token::TYPE_MUTATION: |
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| 49 | 16 | foreach ($this->parseBody(Token::TYPE_MUTATION) as $query) { |
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| 50 | 11 | $this->data['mutations'][] = $query; |
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| 51 | } |
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| 52 | |||
| 53 | 11 | break; |
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| 54 | |||
| 55 | 9 | case Token::TYPE_FRAGMENT: |
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| 56 | 8 | $this->data['fragments'][] = $this->parseFragment(); |
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| 57 | |||
| 58 | 8 | break; |
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| 59 | |||
| 60 | default: |
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| 61 | 1 | throw new SyntaxErrorException('Incorrect request syntax', $this->getLocation()); |
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| 62 | } |
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| 63 | } |
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| 64 | |||
| 65 | 86 | return $this->data; |
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| 66 | } |
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| 67 | |||
| 68 | 96 | private function init($source = null) |
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| 69 | { |
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| 70 | 96 | $this->initTokenizer($source); |
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| 71 | |||
| 72 | 96 | $this->data = [ |
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| 73 | 'queries' => [], |
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| 74 | 'mutations' => [], |
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| 75 | 'fragments' => [], |
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| 76 | 'fragmentReferences' => [], |
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| 77 | 'variables' => [], |
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| 78 | 'variableReferences' => [] |
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| 79 | ]; |
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| 80 | 96 | } |
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| 81 | |||
| 82 | 94 | protected function parseBody($token = Token::TYPE_QUERY, $highLevel = true) |
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| 83 | { |
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| 84 | 94 | $fields = []; |
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| 85 | |||
| 86 | 94 | if ($highLevel && $this->peek()->getType() === $token) { |
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| 87 | 40 | $this->lex(); |
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| 88 | 40 | $this->eat(Token::TYPE_IDENTIFIER); |
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| 89 | |||
| 90 | 40 | if ($this->match(Token::TYPE_LPAREN)) { |
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| 91 | 11 | $this->parseVariables(); |
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| 92 | } |
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| 93 | } |
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| 94 | |||
| 95 | 94 | $this->lex(); |
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| 96 | |||
| 97 | 94 | while (!$this->match(Token::TYPE_RBRACE) && !$this->end()) { |
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| 98 | 91 | if ($this->match(Token::TYPE_FRAGMENT_REFERENCE)) { |
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| 99 | 10 | $this->lex(); |
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| 100 | |||
| 101 | 10 | if ($this->eat(Token::TYPE_ON)) { |
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| 102 | 3 | $fields[] = $this->parseBodyItem(Token::TYPE_TYPED_FRAGMENT, $highLevel); |
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| 103 | } else { |
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| 104 | 10 | $fields[] = $this->parseFragmentReference(); |
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| 105 | } |
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| 106 | } else { |
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| 107 | 91 | $fields[] = $this->parseBodyItem($token, $highLevel); |
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| 108 | } |
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| 109 | } |
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| 110 | |||
| 111 | 86 | $this->expect(Token::TYPE_RBRACE); |
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| 112 | |||
| 113 | 86 | return $fields; |
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| 114 | } |
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| 115 | |||
| 116 | 11 | protected function parseVariables() |
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| 117 | { |
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| 118 | 11 | $this->eat(Token::TYPE_LPAREN); |
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| 119 | |||
| 120 | 11 | while (!$this->match(Token::TYPE_RPAREN) && !$this->end()) { |
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| 121 | 11 | $variableToken = $this->eat(Token::TYPE_VARIABLE); |
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| 122 | 11 | $nameToken = $this->eatIdentifierToken(); |
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| 123 | 11 | $this->eat(Token::TYPE_COLON); |
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| 124 | |||
| 125 | 11 | $isArray = false; |
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| 126 | 11 | $arrayElementNullable = true; |
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| 127 | |||
| 128 | 11 | if ($this->match(Token::TYPE_LSQUARE_BRACE)) { |
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| 129 | 2 | $isArray = true; |
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| 130 | |||
| 131 | 2 | $this->eat(Token::TYPE_LSQUARE_BRACE); |
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| 132 | 2 | $type = $this->eatIdentifierToken()->getData(); |
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| 133 | |||
| 134 | 2 | if ($this->match(Token::TYPE_REQUIRED)) { |
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| 135 | 2 | $arrayElementNullable = false; |
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| 136 | 2 | $this->eat(Token::TYPE_REQUIRED); |
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| 137 | } |
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| 138 | |||
| 139 | 2 | $this->eat(Token::TYPE_RSQUARE_BRACE); |
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| 140 | } else { |
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| 141 | 10 | $type = $this->eatIdentifierToken()->getData(); |
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| 142 | } |
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| 143 | |||
| 144 | 11 | $required = false; |
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| 145 | 11 | if ($this->match(Token::TYPE_REQUIRED)) { |
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| 146 | 2 | $required = true; |
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| 147 | 2 | $this->eat(Token::TYPE_REQUIRED); |
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| 148 | } |
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| 149 | |||
| 150 | 11 | $this->data['variables'][] = new Variable( |
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| 151 | 11 | $nameToken->getData(), |
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| 152 | $type, |
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| 153 | $required, |
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| 154 | $isArray, |
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| 155 | 11 | new Location($variableToken->getLine(), $variableToken->getColumn()), |
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| 156 | $arrayElementNullable |
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| 157 | ); |
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| 158 | } |
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| 159 | |||
| 160 | 11 | $this->expect(Token::TYPE_RPAREN); |
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| 161 | 11 | } |
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| 162 | |||
| 163 | 91 | protected function expectMulti($types) |
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| 171 | |||
| 172 | 10 | protected function parseVariableReference() |
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| 173 | { |
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| 174 | 10 | $startToken = $this->expectMulti([Token::TYPE_VARIABLE]); |
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| 175 | |||
| 176 | 10 | if ($this->match(Token::TYPE_NUMBER) || $this->match(Token::TYPE_IDENTIFIER) || $this->match(Token::TYPE_QUERY)) { |
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| 177 | 10 | $name = $this->lex()->getData(); |
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| 178 | |||
| 179 | 10 | $variable = $this->findVariable($name); |
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| 180 | 10 | if ($variable) { |
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| 181 | 10 | $variable->setUsed(true); |
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| 182 | } |
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| 183 | |||
| 184 | 10 | $variableReference = new VariableReference($name, $variable, new Location($startToken->getLine(), $startToken->getColumn())); |
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| 185 | |||
| 186 | 10 | $this->data['variableReferences'][] = $variableReference; |
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| 187 | |||
| 188 | 10 | return $variableReference; |
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| 189 | } |
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| 190 | |||
| 191 | throw $this->createUnexpectedException($this->peek()); |
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| 192 | } |
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| 193 | |||
| 194 | 10 | protected function findVariable($name) |
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| 195 | { |
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| 196 | 10 | foreach ($this->data['variables'] as $variable) { |
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| 197 | /** @var $variable Variable */ |
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| 198 | 10 | if ($variable->getName() == $name) { |
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| 199 | 10 | return $variable; |
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| 200 | } |
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| 201 | } |
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| 202 | |||
| 203 | return null; |
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| 204 | } |
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| 205 | |||
| 206 | 8 | protected function parseFragmentReference() |
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| 215 | |||
| 216 | 91 | protected function eatIdentifierToken() |
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| 217 | { |
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| 218 | 91 | return $this->expectMulti([ |
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| 219 | 91 | Token::TYPE_IDENTIFIER, |
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| 220 | 91 | Token::TYPE_MUTATION, |
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| 221 | 91 | Token::TYPE_QUERY, |
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| 225 | |||
| 226 | 91 | protected function parseBodyItem($type = Token::TYPE_QUERY, $highLevel = true) |
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| 263 | |||
| 264 | 54 | protected function parseArgumentList() |
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| 278 | |||
| 279 | 54 | protected function parseArgument() |
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| 287 | |||
| 288 | /** |
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| 289 | * @return array|InputList|InputObject|Literal|VariableReference |
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| 290 | * |
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| 291 | * @throws SyntaxErrorException |
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| 292 | */ |
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| 293 | 53 | protected function parseValue() |
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| 318 | |||
| 319 | 9 | protected function parseList($createType = true) |
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| 332 | |||
| 333 | 15 | protected function parseListValue() |
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| 356 | |||
| 357 | 9 | protected function parseObject($createType = true) |
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| 374 | |||
| 375 | 8 | protected function parseFragment() |
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| 387 | |||
| 388 | 93 | protected function eat($type) |
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| 396 | |||
| 397 | protected function eatMulti($types) |
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| 405 | |||
| 406 | 91 | protected function matchMulti($types) |
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| 416 | } |
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| 417 |
This check marks implicit conversions of arrays to boolean values in a comparison. While in PHP an empty array is considered to be equal (but not identical) to false, this is not always apparent.
Consider making the comparison explicit by using
empty(..)or! empty(...)instead.