Default to false removeDuplicates when instantiating Readline

[Fludem]

Description

A user experienced this error when using Laravel Tinker:

Cannot assign null to property Psy\Readline\Transient::$eraseDups of type bool
at vendor/psy/psysh/src/Readline/Transient.php:53

Cause of bug

The error is caused by line 53 of Transient.php, where the constructor sets the value of $eraseDups.

The constructor has this signature:

public function __construct($historyFile = null, $historySize = 0, $eraseDups = false)

Types are not declared(Parent does declare). When this constructor is used with the parameters explicitly being null, it will overwrite defaults in PHP8.0 and greater.

In the constructor body, it sets the value of the eraseDups variable.

private bool $eraseDups; // Variable declared at the top of the class

$this->eraseDups = $eraseDups; // Inside the constructor body

This can result in the constructor trying to assign null to the $eraseDups variable. This causes an error as the variable is not declared nullable.

Changes made

Configuration.php

Pass the default value of false when instantiating the ReadLine class in the getReadLine function.

 public function getReadline(): Readline\Readline
    {
        if (!isset($this->readline)) {
            $className = $this->getReadlineClass();
            $this->readline = new $className(
                $this->getHistoryFile(),
                $this->getHistorySize(),
                $this->getEraseDuplicates() ?? false // Added ternary operator to use false if null
            );
        }

        return $this->readline;
    }

The setEraseDuplicates function type casting was removed. It wasn't related to this bug, but the function signature declares the type as bool, making the cast redundant.

$this->eraseDuplicates = (bool) $value; // old
$this->eraseDuplicates = $value; // new

Transient.php

The constructor now sets the value of eraseDups to false if the parameter is null.

$this->eraseDups = $eraseDups ?? false;

The constructor also sets a default history size where the parameter is null.

$this->historySize = $historySize ?? 0;

Updated function signature with types

public function __construct($historyFile = null, ?int $historySize = 0, ?bool $eraseDups = false)

Readline.php (Interface)

Updated constructor signature with more accurate type declarations.

 public function __construct($historyFile = null, ?int $historySize = 0, ?bool $eraseDups = false);

[Fludem]

Fixes #843

[Fludem]

Few extra notes.

Configuration.php

The erase duplicates property has maintained nullability. I'm not sure why this should or shouldn't be nullable. Leaving it unchanged should avoid breaking anything.

Transient.php

The class property has also maintained its previous nullability.

The history size was also updated to use a default value in the constructor. Previously, it could have caused problems similar to those of erasing duplicates.

[bobthecow]

Thank you!