Cognitive Complexity

Cognitive Complexity is a measure of how difficult a unit of code is to intuitively understand. Unlike Cyclomatic Complexity, which determines how difficult your code will be to test, Cognitive Complexity tells you how difficult your code will be to read and comprehend.

A method's cognitive complexity is based on a few simple rules:

• Code is not considered more complex when it uses shorthand that the language provides for collapsing multiple statements into one
• Code is considered more complex for each "break in the linear flow of the code"
• Code is considered more complex when "flow breaking structures are nested"

Further reading

• Cognitive Complexity docs
• Cognitive Complexity: A new way of measuring understandability

ErrorControlOperator

Error suppression should be avoided if possible as it doesn't just suppress the error, that you are trying to stop, but will also suppress errors that you didn't predict would ever occur. Consider changing error_reporting() level and/or setting up your own error handler.

Example

function foo($filePath) {
    $file = @fopen($filPath); // hides exceptions
    $key = @$array[$notExistingKey]; // assigns null to $key
}

Source http://phpmd.org/rules/cleancode.html#errorcontroloperator

EmptyCatchBlock

Since: 2.7.0

Usually empty try-catch is a bad idea because you are silently swallowing an error condition and then continuing execution. Occasionally this may be the right thing to do, but often it's a sign that a developer saw an exception, didn't know what to do about it, and so used an empty catch to silence the problem.

Example

class Foo {

  public function bar()
  {
      try {
          // ...
      } catch (Exception $e) {} // empty catch block
  }
}

Source https://phpmd.org/rules/design.html#emptycatchblock

ShortMethodName

Since: 0.2

Detects when very short method names are used.

Example

class ShortMethod {
    public function a( $index ) { // Violation
    }
}

Source https://phpmd.org/rules/naming.html#shortmethodname

ShortMethodName

Since: 0.2

Detects when very short method names are used.

Example

class ShortMethod {
    public function a( $index ) { // Violation
    }
}

Source https://phpmd.org/rules/naming.html#shortmethodname

CamelCaseClassName

Since: 0.2

It is considered best practice to use the CamelCase notation to name classes.

Example

class class_name {
}

Source

CamelCaseMethodName

Since: 0.2

It is considered best practice to use the camelCase notation to name methods.

Example

class ClassName {
    public function get_name() {
    }
}

Source