[REF][PHP8.2] Declare property _amount on event confirm form

[braders]

Overview

Declare property _amount on event confirm form

Before

Test failures on PHP 8.2, for example:

CRM_Event_Form_Registration_ConfirmTest::testNoCalendarLinks
Creation of dynamic property CRM_Event_Form_Registration_Confirm::$_amount is deprecated

After

Property declared.

Technical Details

I'd assumed that _amount would be deeply interwined amongst multiple classes, but once I dug into it, that turned out not to be the case.

That said, this property is fairly confusing. Elsewhere in Civi, _amount is a float (e.g. in CRM_Contribute_Form_Contribution_Confirm). However, here it's an array, and there is is no overlap between these different types of _amount.

Just to further confuse things, the deprecated testSubmit() sets _amount to a number, which works because _amount is largely used as a truthy check in if statements. However, testSubmit() is deprecated, so I don't think it matters to much.

I have added a comment to the code explaining this confusion, and in time moving to getter functions probably makes sense. In the meantime this gets us closer to PHP 8.2 support.

@eileenmcnaughton This relates to this PR from a couple of days ago, so worth you taking a look at this.

[civibot]

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[eileenmcnaughton]

@braders I guess this gets us past the fails but I think I'd rather it was tagged deprecated & the comment said something more like - this property is going to be changed or removed so if you access it your code will break

[eileenmcnaughton]

@braders I actually think we should go full private on this one - it is the wrong property doing the wrong thing in the wrong place & it actively makes the code harder to maintain. There has never been a commitment to maintain all non-api properties on form classes & especially not ones with no definition. I guess I have one thought about how to deprecate it -I'll have a go at that...

[eileenmcnaughton]

@braders what about this ? #28769

[eileenmcnaughton]

Closing this as the alternate was merged