Modified to change handling of existing and updated due values

current_payment_instructions view used in place of the new
payment_instructions_due table which has now been removed

New update_due method added to participant to carry over existing
due values to new (modified) payment instructions

gratipay/billing/payday.py

@@ -347,21 +347,6 @@ def update_balances(cursor):
                 SELECT *, (SELECT id FROM paydays WHERE extract(year from ts_end) = 1970)
                   FROM payday_payments;
         """)
-        # Copy due value back to payment_instructions
-        cursor.run("""
-            UPDATE payment_instructions pi
-               SET due = pi2.due
-              FROM payment_instructions_due pi2
-             WHERE pi.id = pi2.id
-        """)
-        # Reset older due values to zero
-        cursor.run("""
-            UPDATE payment_instructions pi
-               SET due = '0'
-             WHERE pi.id NOT IN (
-                 SELECT id
-                   FROM payment_instructions_due pi2)
-        """)
 
         log("Updated the balances of %i participants." % len(participants))
 

gratipay/models/participant.py

@@ -854,10 +854,13 @@ def set_payment_instruction(self, team, amount, update_self=True, update_team=Tr
         """
         args = dict(participant=self.username, team=team.slug, amount=amount)
         t = (cursor or self.db).one(NEW_PAYMENT_INSTRUCTION, args)
+        t_dict = t._asdict()
 
         if update_self:
             # Update giving amount of participant
             self.update_giving(cursor)
+            # Carry over any existing due
+            self.update_due(t_dict['team'],t_dict['id'],cursor)
         if update_team:
             # Update receiving amount of team
             team.update_receiving(cursor)
@@ -1002,6 +1005,31 @@ def update_giving(self, cursor=None):
 
         return updated
 
+    def update_due(self, team, id, cursor=None):
+        """Transfer existing due value to newly inserted record
+        """
+        # Copy due to new record
+        (cursor or self.db).run("""
+            UPDATE payment_instructions p
+               SET due = COALESCE((
+                      SELECT due
+                        FROM payment_instructions s
+                       WHERE participant=%(username)s
+                         AND team = %(team)s
+                         AND due > 0
+                   ), 0)
+             WHERE p.id = %(id)s
+        """, dict(username=self.username,team=team,id=id))
+
+        # Reset older due values to 0
+        (cursor or self.db).run("""
+            UPDATE payment_instructions p
+               SET due = 0
+             WHERE participant = %(username)s
+               AND team = %(team)s
+               AND due > 0
+               AND p.id != %(id)s
+        """, dict(username=self.username,team=team,id=id))
 
     def update_taking(self, cursor=None):
         (cursor or self.db).run("""

sql/payday.sql

@@ -76,21 +76,6 @@ CREATE INDEX ON payday_payment_instructions (participant);
 CREATE INDEX ON payday_payment_instructions (team);
 ALTER TABLE payday_payment_instructions ADD COLUMN is_funded boolean;
 
-UPDATE payday_payment_instructions ppi
-   SET due = s.due
-  FROM (SELECT participant, team, SUM(due) AS due
-       FROM payment_instructions
-       GROUP BY participant, team) s
- WHERE ppi.participant = s.participant
-   AND ppi.team = s.team;
-
-DROP TABLE IF EXISTS payment_instructions_due;
-CREATE TABLE payment_instructions_due AS
-    SELECT * FROM payday_payment_instructions;
-
-CREATE INDEX ON payment_instructions_due (participant);
-CREATE INDEX ON payment_instructions_due (team);
-
 ALTER TABLE payday_participants ADD COLUMN giving_today numeric(35,2);
 UPDATE payday_participants pp
    SET giving_today = COALESCE((
@@ -141,7 +126,7 @@ RETURNS void AS $$
         UPDATE payday_teams
            SET balance = (balance + team_delta)
          WHERE slug = $2;
-        UPDATE payment_instructions_due
+        UPDATE current_payment_instructions
            SET due = 0
          WHERE participant = $1
            AND team = $2
@@ -176,7 +161,7 @@ RETURNS void AS $$
     BEGIN
         IF ($3 = 0) THEN RETURN; END IF;
 
-        UPDATE payment_instructions_due
+        UPDATE current_payment_instructions
            SET due = $3
          WHERE participant = $1
            AND team = $2;

tests/py/test_billing_payday.py

@@ -92,7 +92,6 @@ def test_payday_preserves_due_until_charged(self, fch):
         fch.return_value = {}
         Payday.start().run()    # payday 4
 
-
         obama = Participant.from_username('obama')
         picard = Participant.from_username('picard')