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:
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| 9 | trait CommonImmMutableContainerTrait |
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| 10 | { |
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| 11 | /** |
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| 12 | * {@inheritdoc} |
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| 13 | */ |
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| 14 | public function values() |
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| 19 | public function keys() |
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| 24 | /** |
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| 25 | * {@inheritDoc} |
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| 26 | */ |
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| 27 | View Code Duplication | public function concat($iterable) |
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| 39 | } |
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This check looks for methods that are used by a trait but not required by it.
To illustrate, let’s look at the following code example
The trait
Idableprovides a methodequalsIdthat in turn relies on the methodgetId(). If this method does not exist on a class mixing in this trait, the method will fail.Adding the
getId()as an abstract method to the trait will make sure it is available.