[CodeQuality] Change behaviour of OptionalParametersAfterRequiredRector to fill null default value when previous param is optional

[samsonasik]

@afaibyshev @calebdw @TomasVotruba this is possible solution for

Fixes rectorphp/rector#9317

instead of swap param/argument, fill it with default value null instead.

[samsonasik]

I will verify the usage when on types as well.

[samsonasik]

I add for param typed dd8cca8

[samsonasik]

I add requirement for PhpVersionFeature::NULLABLE_TYPE for it, so ensure mark to nullable on param always work 7eb8a4e

[samsonasik]

All checks have passed 🎉 @TomasVotruba it is ready for review.

[TomasVotruba]

Looks good 👍

[samsonasik]

This seems can be improved for more reasonable default value. I am thinking of add null default value should only on Nullable, UnionType and/or non-scalar, otherwise, use its basic type value to avoid next user use invalid, eg nullable and use as arithmetic task.

MixedType: Ok to add null default value

• $a --> null
• mixed $a = null

Nullable/Union with nullable: Ok to add null default value

?AnyTipe --> null
A|B|null --> null

Scalar:

• int --> 0
• float -> 0.0
• bool --> false
• string --> ""

Array

• array --> []

Union + Scalar: use first type basic value

• int+float --> 0
• int + string --> 0
• bool + int/float --> false
• etc

Object type + union: nullable

• stdClass|DateTime = null|stdClass|DateTime
• stdClass = ?stdClass

This will require some proper maps, I will look into it.

[samsonasik]

After some thinking, just remove previous params default is better, since even on named argument usage, the value is always null if not defined, see

https://3v4l.org/0jdGl

I will look into it..., to see if there is drawback, eg; on override method, etc

[samsonasik]

On PHP 8.0, it seems not fatal error when optional is not filled before required, see https://3v4l.org/0jdGl#v8.0.0

got:

Deprecated: Required parameter $req follows optional parameter $op in /in/0jdGl on line 3
1
foo

On PHP 8.1, it seems cause fatal error when optioanl is not filed before required, see https://3v4l.org/0jdGl#v8.1.12

got:

Deprecated: Optional parameter $op declared before required parameter $req is implicitly treated as a required parameter in /in/0jdGl on line 3

Fatal error: Uncaught ArgumentCountError: run(): Argument #1 ($op) not passed in /in/0jdGl:3
Stack trace:
#0 /in/0jdGl(12): run(NULL, 'foo')
#1 {main}
  thrown in /in/0jdGl on line 3

so add default reasonable value by type seems be better, I will look more deep into it :)

[samsonasik]

I created new PR to fill reasonable default value, so default value on previous params keep working

• [CodeQuality] Fill reasonable default value on OptionalParametersAfterRequiredRector #7226