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 Yaml 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 Yaml, and based on these observations, apply Extract Interface, too.
| 1 | <?php  | 
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| 12 | class Yaml  | 
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| 13 | { | 
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| 14 | /**  | 
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| 15 | * @const string  | 
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| 16 | */  | 
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| 17 | const BEFORE_FLAG = 'before';  | 
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| 18 | |||
| 19 | /**  | 
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| 20 | * @const string  | 
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| 21 | */  | 
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| 22 | const AFTER_FLAG = 'after';  | 
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| 23 | |||
| 24 | /**  | 
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| 25 | * @var string  | 
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| 26 | */  | 
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| 27 | const ONLY_FLAG = 'only';  | 
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| 28 | |||
| 29 | /**  | 
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| 30 | * @var string  | 
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| 31 | */  | 
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| 32 | const EXCEPT_FLAG = 'except';  | 
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| 33 | |||
| 34 | /**  | 
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| 35 | * A list of files. Real, full path.  | 
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| 36 | *  | 
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| 37 | * @var array  | 
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| 38 | */  | 
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| 39 | protected $files = [];  | 
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| 40 | |||
| 41 | /**  | 
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| 42 | * Store the yaml document content as an array.  | 
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| 43 | *  | 
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| 44 | * @var array  | 
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| 45 | */  | 
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| 46 | protected $documents = [];  | 
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| 47 | |||
| 48 | /**  | 
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| 49 | * @var int  | 
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| 50 | */  | 
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| 51 | protected $sort;  | 
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| 52 | |||
| 53 | /**  | 
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| 54 | * Base directory used to find yaml files.  | 
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| 55 | *  | 
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| 56 | * @var string  | 
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| 57 | */  | 
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| 58 | protected $baseDirectory;  | 
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| 59 | |||
| 60 | /**  | 
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| 61 | * A list of closures to be used in only/except rules.  | 
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| 62 | *  | 
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| 63 | * @var Closure[]  | 
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| 64 | */  | 
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| 65 | protected $rules = [];  | 
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| 66 | |||
| 67 | /**  | 
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| 68 | * @param string $dir directory to scan for yaml files  | 
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| 69 | */  | 
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| 70 | 14 | public function __construct($baseDir, Finder $finder, $sort = 0)  | 
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| 79 | |||
| 80 | /**  | 
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| 81 | * This is responsible for parsing a single yaml file and returning it into a format  | 
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| 82 | * that Config can understand. Config will then be responsible for turning thie  | 
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| 83 | * output into the final merged config.  | 
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| 84 | *  | 
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| 85 | * @return array  | 
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| 86 | */  | 
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| 87 | 14 | public function transform()  | 
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| 106 | |||
| 107 | /**  | 
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| 108 | * This allows external rules to be added to only/except checks. Config is only  | 
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| 109 | * supposed to be setup once, so adding rules is a one-way system. You cannot  | 
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| 110 | * remove rules after being set. This also prevent built-in rules from being  | 
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| 111 | * removed.  | 
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| 112 | *  | 
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| 113 | * @param string $rule  | 
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| 114 | * @param Closure $func  | 
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| 115 | */  | 
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| 116 | 5 | public function addRule($rule, Closure $func)  | 
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| 121 | |||
| 122 | /**  | 
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| 123 | * Checks to see if a rule is present  | 
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| 124 | *  | 
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| 125 | * @var string  | 
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| 126 | *  | 
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| 127 | * @return boolean  | 
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| 128 | */  | 
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| 129 | 4 | protected function hasRule($rule)  | 
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| 134 | |||
| 135 | /**  | 
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| 136 | * This allows config to ignore only/except rules that have been set. This enables  | 
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| 137 | * apps to ignore built-in rules without causing errors where a rule is undefined.  | 
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| 138 | * This, is a one-way system and is only meant to be configured once. When you  | 
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| 139 | * ignore a rule, you cannot un-ignore it.  | 
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| 140 | *  | 
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| 141 | * @param string $rule  | 
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| 142 | */  | 
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| 143 | 1 | public function ignoreRule($rule)  | 
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| 148 | |||
| 149 | /**  | 
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| 150 | * Checks to see if a rule is ignored  | 
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| 151 | *  | 
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| 152 | * @param string $rule  | 
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| 153 | *  | 
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| 154 | * @return boolean  | 
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| 155 | */  | 
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| 156 | 5 | protected function isRuleIgnored($rule)  | 
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| 161 | |||
| 162 | /**  | 
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| 163 | * Returns an array of YAML documents keyed by name.  | 
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| 164 | *  | 
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| 165 | * @return array;  | 
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| 166 | */  | 
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| 167 | 14 | protected function getNamedYamlDocuments()  | 
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| 207 | |||
| 208 | /**  | 
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| 209 | * Because multiple documents aren't supported in symfony/yaml, we have to manually  | 
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| 210 | * split the files up into their own documents before running them through the parser.  | 
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| 211 | * Note: This is not a complete implementation of multi-document YAML parsing. There  | 
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| 212 | * are valid yaml cases where this will fail, however they don't match our use-case.  | 
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| 213 | *  | 
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| 214 | * @return array  | 
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| 215 | */  | 
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| 216 | 14 | protected function splitYamlDocuments()  | 
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| 270 | |||
| 271 | /**  | 
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| 272 | * This generates an array of all document depndencies, keyed by document name.  | 
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| 273 | *  | 
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| 274 | * @param array $documents  | 
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| 275 | *  | 
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| 276 | * @return array  | 
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| 277 | */  | 
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| 278 | 13 | protected function calculateDependencies($documents)  | 
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| 320 | |||
| 321 | /**  | 
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| 322 | * Incapsulates the logic for adding before/after dependencies.  | 
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| 323 | *  | 
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| 324 | * @param array|string $currentDocument  | 
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| 325 | * @param string $name  | 
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| 326 | * @param string $flag  | 
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| 327 | * @param array $dependencies  | 
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| 328 | * @param array $documents  | 
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| 329 | *  | 
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| 330 | * @return array  | 
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| 331 | */  | 
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| 332 | 6 | protected function addDependencies($currentDocument, $name, $flag, $dependencies, $documents)  | 
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| 374 | |||
| 375 | /**  | 
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| 376 | * This returns an array of documents which match the given pattern. The pattern is  | 
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| 377 | * expected to come from before/after blocks of yaml (eg. framwork/*).  | 
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| 378 | *  | 
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| 379 | * @param string $pattern  | 
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| 380 | * @param array  | 
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| 381 | *  | 
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| 382 | * @return array  | 
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| 383 | */  | 
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| 384 | 6 | protected function getMatchingDocuments($pattern, $documents)  | 
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| 440 | |||
| 441 | /**  | 
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| 442 | * We need this to make the path relative from the base directory. We can't use realpath  | 
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| 443 | * or relative path in Finder because we use a virtual filesystem in testing which  | 
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| 444 | * doesn't support these methods.  | 
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| 445 | *  | 
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| 446 | * @param string $filename  | 
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| 447 | *  | 
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| 448 | * @return string  | 
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| 449 | */  | 
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| 450 | 1 | protected function makeRelative($filename)  | 
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| 459 | |||
| 460 | /**  | 
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| 461 | * This method gets all headers and all yaml documents and stores them respectively.  | 
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| 462 | *  | 
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| 463 | * @return array a list of sorted yaml documents  | 
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| 464 | */  | 
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| 465 | 14 | protected function getSortedYamlDocuments()  | 
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| 491 | |||
| 492 | 14 | protected function filterByOnlyAndExcept($documents)  | 
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| 515 | |||
| 516 | 5 | protected function testRules($header, $flag)  | 
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| 535 | |||
| 536 | /**  | 
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| 537 | * Tests a rule against the given expected result.  | 
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| 538 | *  | 
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| 539 | * @param string $rule  | 
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| 540 | * @param string|array $params  | 
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| 541 | *  | 
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| 542 | * @return boolean  | 
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| 543 | */  | 
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| 544 | 4 | protected function testSingleRule($rule, $params)  | 
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| 563 | }  | 
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| 564 | 
This check looks for PHPDoc comments describing methods or function parameters that do not exist on the corresponding method or function.
Consider the following example. The parameter
$italyis not defined by the methodfinale(...).The most likely cause is that the parameter was removed, but the annotation was not.