Don't flag vouchers/discounts as used until multireg completed

If the invoice details are not filled in, we generate an error in the
form. But at the time we had already flagged the voucher/code as used,
and thus the next create would now fail saying the code has already been
used.

Fix this by setting a savepoint at the beginning and roll back to it in
the failure case.

diff --git a/postgresqleu/confreg/views.py b/postgresqleu/confreg/views.py
index f57b2bb7db3da6893c09ccbb9bf54ef6366352a6..40b283db861e02eb44de71493e75664e54c2013b 100644 (file)
--- a/postgresqleu/confreg/views.py
+++ b/postgresqleu/confreg/views.py
@@ -479,6 +479,8 @@ def multireg_newinvoice(request, confname):
                return HttpResponseRedirect('../')
 
        finalize = (request.method == 'POST' and request.POST['submit'] == 'Create')
+       if finalize:
+               savepoint = transaction.savepoint()
 
        # Almost like a bulk invoice, but we know the registrations were
     # created so they exist.
@@ -510,6 +512,7 @@ def multireg_newinvoice(request, confname):
                form = MultiRegInvoiceForm(data=request.POST)
                if totalwithvat != Decimal(request.POST['totalwithvat']):
                        errors.append('Total amount has changed, likely due to a registration being concurrently changed. Please try again.')
+                       # Error set, so will fall through into the path that rolls back
 
                if form.is_valid() and not errors:
                        if totalwithvat == 0:
@@ -527,6 +530,10 @@ def multireg_newinvoice(request, confname):
 
                                return HttpResponseRedirect("../b{0}/".format(bp.id))
 
+               # If we flagged discount codes etc as used, but came down her in the error path,
+           # make sure we roll back the change.
+               transaction.savepoint_rollback(savepoint)
+
                # Add the errors to the form, so they're actually visible.
                for e in errors:
                        form.add_error(None, e)