feat: add new setter/getter for Entity

[kenjis]

Needs #7208

Description
Add special getter/setter to Entity to avoid method name conflicts.

• add new special setter method "_set + key" for a attribute
• add new special getter method "_get + key" for a attribute

Checklist:

• Securely signed commits
• Component(s) with PHPDoc blocks, only if necessary or adds value
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide

[MGatner]

I'm not sure what this is needed for? bar:foo

[kenjis]

For method name collision. #5762 (comment)

[MGatner]

I meant the colons in the value, but now I see those are an artifact of the test fixture, not part of the code! My mistake.

[MGatner]

Looks good, pending docs.

[kenjis]

Added docs.

[kenjis]

@mostafakhudair @najdanovicivan @iRedds @the-gt99 @lonnieezell
Any comments?

[najdanovicivan]

I think this adds a lot of unnecessary complexity to have multiple ways of defining setters. So far the only problem we have is when we need to override setAttributes method. Since now we have setAttributes as deprecated and we're going forward with injectRawData() method. I'd rather use https://www.php.net/manual/en/reflectionmethod.getdeclaringclass.php to check if setAttributes is not from CodeIgniter\Entity or CodeIgniter\Entity\Entity class. So if method is not from base CI4 classes it can be handled as regular setter for $this->attributes['attributes']. The only problem with this one is BC in Entity classes which override the setAttributes method.

[kenjis]

@najdanovicivan Thank you for your opinion.

The main reason of this PR is to avoid setter/getter method name conflicts,
not only for setAttributes().
See https://github.com/codeigniter4/CodeIgniter4/pull/7230/files#diff-b43fcc536c7ffa370ea5d043988d111223780b2dade0198d7b91818f9bd7ab62

[MGatner]

Docs look good.

[iRedds]

As far as I remember, PSR does not recommend using the underscore character as a prefix for method names.
I have already expressed my opinion about the names of methods for accessing attributes more than once.
get<name>Attribute

[kenjis]

We don't remove get<name>() getter.
So get<name>Attribute() may conflict to another column.

If there are columns parent and parent_attribute and
getParent() and getParentAttribute(),
getParentAttribute() is used when getting parent.
This is a breaking change.