fix: prevent fatal error when click on resend receipt

[ravinderk]

Bug Report

User Story

As an admin, I want to resend receipt without any failure.

ref: https://secure.helpscout.net/conversation/796694823/35676?folderId=848135#thread-2266009265

Current Behavior

I am getting a fatal error when click on resend receipt.

Expected Behavior

Resend receipt without any fatal error.

Bug Type

• This bug describes functionality that once worked as expected in version X.X.X.
• This bug describes functionality that never worked as expected.
• I am not sure whether this functionality ever worked as expected.

Steps to Reproduce

1. Add {donation_history_link} or {subscriptions_link} [or both] email to receipt
2. Click on resend receipt button for any of donation
3. you will get an error:

Call to a member function set_verify_key() on a non-object in /wp-content/plugins/give/includes/emails/class-give-email-tags.php on line 1238

Visuals

Possible Solution

Above mentioned email tags use Give_Email_Access class in logic but after refactoring that class only available only on the frontend, so to prevent fatal error we can load this class as backward compatibility on specific resend receipt event [ either bulk or single]

To prevent fatal error we can load this class for this email tag code.
ref: #3871

Acceptance Criteria

• Resend receipt button is working fine when receipt email contains {donation_history_link} email tag.
• Resend receipt button is working fine when receipt email contains {subscriptions_link} email tag.

[Benunc]

Another user reported the same issue with offline donations. To reproduce:

1. Add the {donation_history_link} tag to the donation dreceipt email.
2. Submit an offline donation from the front end
3. Manually mark the donation as complete on the back end.

Error!

[ravinderk]

@Benunc I reviewed the above issue and confirming that it will be fixed by #4069

[ravinderk]

Note: I can reproduce same with subscriptions_link email tag from recurring addon. I updated acceptance criteria of this issue.