pay later membership emails show old (existing) dates

To reproduce the issue (that could use improvement):

• setup a contribution page with memberships and pay later enabled. also enable email receipting.
• create a contact (through the admin side) and create a membership record. To demonstrate the issue clearly, backdate the membership.
• use the newly created contribution page to renew the individual's membership
• observe the email receipt: the membership start/end dates reflect the membership prior to renewal

This is arguably not a true bug – Civi is behaving as designed. Whenever a membership is created through a pay later contribution page, the membership is created in pending status along with the contribution. Once the contribution is flipped to completed status, the membership is updated and the start/end dates calculated. A similar behavior happens on renewal – the end date is not extended until the contribution is completed.

The problem is that this is very confusing for the end user. I had a client raise the issue because a member renewed their membership online and the email listed the end date as prior to the current date. Even if paying with the pay later option, most people would expect the email to reflect the renewal-impacted dates.

I think the existing functionality for how the dates are handled is important – most organizations do not want the membership renewed until payment is actually received. But it causes a good bit of confusion for the member who is renewing.

I'm not sure the best way to handle this. My current thought is that we just suppress the dates altogether if the payment was handled by pay later. Whether this is a new membership or renewal – those date fields will not be intuitive and meaningful for the individual receiving it.

I'd like to get the core team and other people's input on the issue.