use deck of existing cards if all use same deck

anki/collection.py

@@ -277,11 +277,22 @@ crt=?, mod=?, scm=?, dty=?, usn=?, ls=?, conf=?""",
         # build map of (nid,ord) so we don't create dupes
         snids = ids2str(nids)
         have = {}
-        for id, nid, ord in self.db.execute(
+        dids = {}
-            "select id, nid, ord from cards where nid in "+snids):
+        for id, nid, ord, did in self.db.execute(
+            "select id, nid, ord, did from cards where nid in "+snids):
+            # existing cards
             if nid not in have:
                 have[nid] = {}
             have[nid][ord] = id
+            # and their dids
+            if nid in dids:
+                if dids[nid] and dids[nid] != did:
+                    # cards are in two or more different decks; revert to
+                    # model default
+                    dids[nid] = None
+            else:
+                # first card or multiple cards in same deck
+                dids[nid] = did
         # build cards for each note
         data = []
         ts = maxID(self.db)
@@ -292,7 +303,7 @@ crt=?, mod=?, scm=?, dty=?, usn=?, ls=?, conf=?""",
             "select id, mid, flds from notes where id in "+snids):
             model = self.models.get(mid)
             avail = self.models.availOrds(model, flds)
-            did = model['did']
+            did = dids.get(nid) or model['did']
             for t in model['tmpls']:
                 doHave = nid in have and t['ord'] in have[nid]
                 # if have ord but empty, add cid to remove list

tests/test_cards.py

@@ -92,3 +92,36 @@ def test_genrem():
     # remHook("remEmptyCards", abort)
     # f.flush()
     # assert len(f.cards()) == 1
+
+def test_gendeck():
+    d = getEmptyDeck()
+    cloze = d.models.byName("Cloze")
+    d.models.setCurrent(cloze)
+    f = d.newNote()
+    f['Text'] = u'{{c1::one}}'
+    d.addNote(f)
+    assert d.cardCount() == 1
+    assert f.cards()[0].did == 1
+    # set the model to a new default deck
+    newId = d.decks.id("new")
+    cloze['did'] = newId
+    d.models.save(cloze)
+    # a newly generated card should share the first card's deck
+    f['Text'] += u'{{c2::two}}'
+    f.flush()
+    assert f.cards()[1].did == 1
+    # and same with multiple cards
+    f['Text'] += u'{{c3::three}}'
+    f.flush()
+    assert f.cards()[2].did == 1
+    # if one of the cards is in a different deck, it should revert to the
+    # model default
+    c = f.cards()[1]
+    c.did = newId
+    c.flush()
+    f['Text'] += u'{{c4::four}}'
+    f.flush()
+    assert f.cards()[3].did == newId
+
+
+