`ngOnChanges` hook does not work in themes

[mwoodiupui]

Describe the bug
When overriding a stock component in a theme, the changes hook is never called. The instance variable compRef is used in src/app/shared/theme-support/themed-component.ts:ngOnChanges but that variable is not set until ngInit runs, and that happens after the first call to ngOnChanges.

I note that none of the stock themeable components implements onChanges so this issue has not caused a problem until now, when I want to make section-upload-file.component.ts themeable.

To Reproduce
Steps to reproduce the behavior:

1. Write a themed replacement component that depends on change notification.
2. Notice that no changes notifications are received.

Expected behavior
All component lifecycle hooks should function in themes.

[mwoodiupui]

SubmissionSectionUploadFileComponent breaks as soon as I introduce ThemedSubmissionSectionUploadFileComponent, before actually creating a new implementation in my theme.

[alexandrevryghem]

This is caused because the ThemedComponent.ngOnChanges() here updates the @Input() variables from the SubmissionSectionUploadFileComponent directly. By updating those variables manually, the ngOnChanges() method is not triggered. The fix would be to call the ngOnChanges() method with these changes instead.

Atmire would like to claim this issue

[tdonohue]

@alexandrevryghem : Sounds good & thanks. Assigning to you and pulling over to the 7.6 board